rfc9051.original   rfc9051.txt 
Network Working Group A. Melnikov, Ed. Internet Engineering Task Force (IETF) A. Melnikov, Ed.
Internet-Draft Isode Ltd Request for Comments: 9051 Isode Ltd
Obsoletes: 3501 (if approved) B. Leiba, Ed. Obsoletes: 3501 B. Leiba, Ed.
Intended status: Standards Track Futurewei Technologies Category: Standards Track Futurewei Technologies
Expires: August 20, 2021 February 16, 2021 ISSN: 2070-1721 August 2021
Internet Message Access Protocol (IMAP) - Version 4rev2 Internet Message Access Protocol (IMAP) - Version 4rev2
draft-ietf-extra-imap4rev2-30
Abstract Abstract
The Internet Message Access Protocol, Version 4rev2 (IMAP4rev2) The Internet Message Access Protocol Version 4rev2 (IMAP4rev2) allows
allows a client to access and manipulate electronic mail messages on a client to access and manipulate electronic mail messages on a
a server. IMAP4rev2 permits manipulation of mailboxes (remote server. IMAP4rev2 permits manipulation of mailboxes (remote message
message folders) in a way that is functionally equivalent to local folders) in a way that is functionally equivalent to local folders.
folders. IMAP4rev2 also provides the capability for an offline IMAP4rev2 also provides the capability for an offline client to
client to resynchronize with the server. resynchronize with the server.
IMAP4rev2 includes operations for creating, deleting, and renaming IMAP4rev2 includes operations for creating, deleting, and renaming
mailboxes, checking for new messages, permanently removing messages, mailboxes; checking for new messages; removing messages permanently;
setting and clearing flags, RFC 5322, RFC 2045 and RFC 2231 parsing, setting and clearing flags; parsing per RFCs 5322, 2045, and 2231;
searching, and selective fetching of message attributes, texts, and searching; and selective fetching of message attributes, texts, and
portions thereof. Messages in IMAP4rev2 are accessed by the use of portions thereof. Messages in IMAP4rev2 are accessed by the use of
numbers. These numbers are either message sequence numbers or unique numbers. These numbers are either message sequence numbers or unique
identifiers. identifiers.
IMAP4rev2 does not specify a means of posting mail; this function is IMAP4rev2 does not specify a means of posting mail; this function is
handled by a mail submission protocol such as the one specified in handled by a mail submission protocol such as the one specified in
RFC 6409. RFC 6409.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on August 20, 2021. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9051.
Copyright Notice Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
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publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 34 skipping to change at line 74
modifications of such material outside the IETF Standards Process. modifications of such material outside the IETF Standards Process.
Without obtaining an adequate license from the person(s) controlling Without obtaining an adequate license from the person(s) controlling
the copyright in such materials, this document may not be modified the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other it for publication as an RFC or to translate it into languages other
than English. than English.
Table of Contents Table of Contents
1. How to Read This Document . . . . . . . . . . . . . . . . . . 5 1. How to Read This Document
1.1. Organization of This Document . . . . . . . . . . . . . . 5 1.1. Organization of This Document
1.2. Conventions Used in This Document . . . . . . . . . . . . 5 1.2. Conventions Used in This Document
1.3. Special Notes to Implementors . . . . . . . . . . . . . . 6 1.3. Special Notes to Implementors
2. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 7 2. Protocol Overview
2.1. Link Level . . . . . . . . . . . . . . . . . . . . . . . 7 2.1. Link Level
2.2. Commands and Responses . . . . . . . . . . . . . . . . . 7 2.2. Commands and Responses
2.2.1. Client Protocol Sender and Server Protocol Receiver . 8 2.2.1. Client Protocol Sender and Server Protocol Receiver
2.2.2. Server Protocol Sender and Client Protocol Receiver . 8 2.2.2. Server Protocol Sender and Client Protocol Receiver
2.3. Message Attributes . . . . . . . . . . . . . . . . . . . 9 2.3. Message Attributes
2.3.1. Message Numbers . . . . . . . . . . . . . . . . . . . 9 2.3.1. Message Numbers
2.3.2. Flags Message Attribute . . . . . . . . . . . . . . . 12 2.3.2. Flags Message Attribute
2.3.3. Internal Date Message Attribute . . . . . . . . . . . 14 2.3.3. Internal Date Message Attribute
2.3.4. [RFC-5322] Size Message Attribute . . . . . . . . . . 14 2.3.4. RFC822.SIZE Message Attribute
2.3.5. Envelope Structure Message Attribute . . . . . . . . 14 2.3.5. Envelope Structure Message Attribute
2.3.6. Body Structure Message Attribute . . . . . . . . . . 14 2.3.6. Body Structure Message Attribute
2.4. Message Texts . . . . . . . . . . . . . . . . . . . . . . 15 2.4. Message Texts
3. State and Flow Diagram . . . . . . . . . . . . . . . . . . . 15 3. State and Flow Diagram
3.1. Not Authenticated State . . . . . . . . . . . . . . . . . 15 3.1. Not Authenticated State
3.2. Authenticated State . . . . . . . . . . . . . . . . . . . 15 3.2. Authenticated State
3.3. Selected State . . . . . . . . . . . . . . . . . . . . . 15 3.3. Selected State
3.4. Logout State . . . . . . . . . . . . . . . . . . . . . . 15 3.4. Logout State
4. Data Formats . . . . . . . . . . . . . . . . . . . . . . . . 18 4. Data Formats
4.1. Atom . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.1. Atom
4.1.1. Sequence set and UID set . . . . . . . . . . . . . . 18 4.1.1. Sequence Set and UID Set
4.2. Number . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.2. Number
4.3. String . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.3. String
4.3.1. 8-bit and Binary Strings . . . . . . . . . . . . . . 19 4.3.1. 8-Bit and Binary Strings
4.4. Parenthesized List . . . . . . . . . . . . . . . . . . . 20 4.4. Parenthesized List
4.5. NIL . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4.5. NIL
5. Operational Considerations . . . . . . . . . . . . . . . . . 21 5. Operational Considerations
5.1. Mailbox Naming . . . . . . . . . . . . . . . . . . . . . 21 5.1. Mailbox Naming
5.1.1. Mailbox Hierarchy Naming . . . . . . . . . . . . . . 22 5.1.1. Mailbox Hierarchy Naming
5.1.2. Namespaces . . . . . . . . . . . . . . . . . . . . . 22 5.1.2. Namespaces
5.2. Mailbox Size and Message Status Updates . . . . . . . . . 24 5.2. Mailbox Size and Message Status Updates
5.3. Response when no Command in Progress . . . . . . . . . . 24 5.3. Response When No Command in Progress
5.4. Autologout Timer . . . . . . . . . . . . . . . . . . . . 24 5.4. Autologout Timer
5.5. Multiple Commands in Progress (Command Pipelining) . . . 25 5.5. Multiple Commands in Progress (Command Pipelining)
6. Client Commands . . . . . . . . . . . . . . . . . . . . . . . 26 6. Client Commands
6.1. Client Commands - Any State . . . . . . . . . . . . . . . 27 6.1. Client Commands - Any State
6.1.1. CAPABILITY Command . . . . . . . . . . . . . . . . . 27 6.1.1. CAPABILITY Command
6.1.2. NOOP Command . . . . . . . . . . . . . . . . . . . . 28 6.1.2. NOOP Command
6.1.3. LOGOUT Command . . . . . . . . . . . . . . . . . . . 28 6.1.3. LOGOUT Command
6.2. Client Commands - Not Authenticated State . . . . . . . . 29 6.2. Client Commands - Not Authenticated State
6.2.1. STARTTLS Command . . . . . . . . . . . . . . . . . . 29 6.2.1. STARTTLS Command
6.2.2. AUTHENTICATE Command . . . . . . . . . . . . . . . . 31 6.2.2. AUTHENTICATE Command
6.2.3. LOGIN Command . . . . . . . . . . . . . . . . . . . . 35 6.2.3. LOGIN Command
6.3. Client Commands - Authenticated State . . . . . . . . . . 35 6.3. Client Commands - Authenticated State
6.3.1. ENABLE Command . . . . . . . . . . . . . . . . . . . 36 6.3.1. ENABLE Command
6.3.2. SELECT Command . . . . . . . . . . . . . . . . . . . 38 6.3.2. SELECT Command
6.3.3. EXAMINE Command . . . . . . . . . . . . . . . . . . . 40 6.3.3. EXAMINE Command
6.3.4. CREATE Command . . . . . . . . . . . . . . . . . . . 41 6.3.4. CREATE Command
6.3.5. DELETE Command . . . . . . . . . . . . . . . . . . . 42 6.3.5. DELETE Command
6.3.6. RENAME Command . . . . . . . . . . . . . . . . . . . 44 6.3.6. RENAME Command
6.3.7. SUBSCRIBE Command . . . . . . . . . . . . . . . . . . 47 6.3.7. SUBSCRIBE Command
6.3.8. UNSUBSCRIBE Command . . . . . . . . . . . . . . . . . 47 6.3.8. UNSUBSCRIBE Command
6.3.9. LIST Command . . . . . . . . . . . . . . . . . . . . 48 6.3.9. LIST Command
6.3.10. NAMESPACE Command . . . . . . . . . . . . . . . . . . 66 6.3.10. NAMESPACE Command
6.3.11. STATUS Command . . . . . . . . . . . . . . . . . . . 71 6.3.11. STATUS Command
6.3.12. APPEND Command . . . . . . . . . . . . . . . . . . . 73 6.3.12. APPEND Command
6.3.13. IDLE Command . . . . . . . . . . . . . . . . . . . . 76 6.3.13. IDLE Command
6.4. Client Commands - Selected State . . . . . . . . . . . . 77 6.4. Client Commands - Selected State
6.4.1. CLOSE Command . . . . . . . . . . . . . . . . . . . . 78 6.4.1. CLOSE Command
6.4.2. UNSELECT Command . . . . . . . . . . . . . . . . . . 78 6.4.2. UNSELECT Command
6.4.3. EXPUNGE Command . . . . . . . . . . . . . . . . . . . 79 6.4.3. EXPUNGE Command
6.4.4. SEARCH Command . . . . . . . . . . . . . . . . . . . 79 6.4.4. SEARCH Command
6.4.5. FETCH Command . . . . . . . . . . . . . . . . . . . . 92 6.4.5. FETCH Command
6.4.6. STORE Command . . . . . . . . . . . . . . . . . . . . 97 6.4.6. STORE Command
6.4.7. COPY Command . . . . . . . . . . . . . . . . . . . . 98 6.4.7. COPY Command
6.4.8. MOVE Command . . . . . . . . . . . . . . . . . . . . 99 6.4.8. MOVE Command
6.4.9. UID Command . . . . . . . . . . . . . . . . . . . . . 101 6.4.9. UID Command
6.5. Client Commands - Experimental/Expansion . . . . . . . . 103 6.5. Client Commands - Experimental/Expansion
7. Server Responses . . . . . . . . . . . . . . . . . . . . . . 103 7. Server Responses
7.1. Server Responses - Generic Status Responses . . . . . . . 104 7.1. Server Responses - Generic Status Responses
7.1.1. OK Response . . . . . . . . . . . . . . . . . . . . . 113 7.1.1. OK Response
7.1.2. NO Response . . . . . . . . . . . . . . . . . . . . . 113 7.1.2. NO Response
7.1.3. BAD Response . . . . . . . . . . . . . . . . . . . . 113 7.1.3. BAD Response
7.1.4. PREAUTH Response . . . . . . . . . . . . . . . . . . 114 7.1.4. PREAUTH Response
7.1.5. BYE Response . . . . . . . . . . . . . . . . . . . . 114 7.1.5. BYE Response
7.2. Server Responses - Server Status . . . . . . . . . . . . 115 7.2. Server Responses - Server Status
7.2.1. ENABLED Response . . . . . . . . . . . . . . . . . . 115 7.2.1. ENABLED Response
7.2.2. CAPABILITY Response . . . . . . . . . . . . . . . . . 115 7.2.2. CAPABILITY Response
7.3. Server Responses - Mailbox Status . . . . . . . . . . . . 117 7.3. Server Responses - Mailbox Status
7.3.1. LIST Response . . . . . . . . . . . . . . . . . . . . 117 7.3.1. LIST Response
7.3.2. NAMESPACE Response . . . . . . . . . . . . . . . . . 121 7.3.2. NAMESPACE Response
7.3.3. STATUS Response . . . . . . . . . . . . . . . . . . . 121 7.3.3. STATUS Response
7.3.4. ESEARCH Response . . . . . . . . . . . . . . . . . . 121 7.3.4. ESEARCH Response
7.3.5. FLAGS Response . . . . . . . . . . . . . . . . . . . 123 7.3.5. FLAGS Response
7.4. Server Responses - Mailbox Size . . . . . . . . . . . . . 123 7.4. Server Responses - Mailbox Size
7.4.1. EXISTS Response . . . . . . . . . . . . . . . . . . . 123 7.4.1. EXISTS Response
7.5. Server Responses - Message Status . . . . . . . . . . . . 123 7.5. Server Responses - Message Status
7.5.1. EXPUNGE Response . . . . . . . . . . . . . . . . . . 123 7.5.1. EXPUNGE Response
7.5.2. FETCH Response . . . . . . . . . . . . . . . . . . . 124 7.5.2. FETCH Response
7.6. Server Responses - Command Continuation Request . . . . . 130 7.6. Server Responses - Command Continuation Request
8. Sample IMAP4rev2 connection . . . . . . . . . . . . . . . . . 131 8. Sample IMAP4rev2 Connection
9. Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . . 132 9. Formal Syntax
10. Author's Note . . . . . . . . . . . . . . . . . . . . . . . . 150 10. Author's Note
11. Security Considerations . . . . . . . . . . . . . . . . . . . 150 11. Security Considerations
11.1. TLS related Security Considerations . . . . . . . . . . 151 11.1. TLS-Related Security Considerations
11.2. STARTTLS command versa use of Implicit TLS port . . . . 151 11.2. STARTTLS Command versus Use of Implicit TLS Port
11.3. Client handling of unsolicited responses not suitable 11.3. Client Handling of Unsolicited Responses Not Suitable for
for the current connection state . . . . . . . . . . . . 152 the Current Connection State
11.4. COPYUID and APPENDUID response codes . . . . . . . . . . 152 11.4. COPYUID and APPENDUID Response Codes
11.5. LIST command and Other Users' namespace . . . . . . . . 153 11.5. LIST Command and Other Users' Namespace
11.6. Use of MD5 . . . . . . . . . . . . . . . . . . . . . . . 153 11.6. Use of MD5
11.7. Other Security Considerations . . . . . . . . . . . . . 153 11.7. Other Security Considerations
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 154 12. IANA Considerations
12.1. Updates to IMAP4 Capabilities registry . . . . . . . . . 154 12.1. Updates to IMAP Capabilities Registry
12.2. GSSAPI/SASL service name . . . . . . . . . . . . . . . . 155 12.2. GSSAPI/SASL Service Name
12.3. LIST Selection Options, LIST Return Options, LIST 12.3. LIST Selection Options, LIST Return Options, and LIST
extended data items . . . . . . . . . . . . . . . . . . 155 Extended Data Items
12.4. IMAP Mailbox Name Attributes and IMAP Response Codes . . 155 12.4. IMAP Mailbox Name Attributes and IMAP Response Codes
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 155 13. References
13.1. Normative References . . . . . . . . . . . . . . . . . . 156 13.1. Normative References
13.2. Informative References (related protocols) . . . . . . . 159 13.2. Informative References
13.3. Informative References (historical aspects of IMAP and 13.2.1. Related Protocols
related protocols) . . . . . . . . . . . . . . . . . . . 162 13.2.2. Historical Aspects of IMAP and Related Protocols
Appendix A. Backward compatibility with IMAP4rev1 . . . . . . . 163 Appendix A. Backward Compatibility with IMAP4rev1
A.1. Mailbox International Naming Convention for compatibility A.1. Mailbox International Naming Convention for Compatibility
with IMAP4rev1 . . . . . . . . . . . . . . . . . . . . . 163 with IMAP4rev1
Appendix B. Backward compatibility with BINARY extension . . . . 165 Appendix B. Backward Compatibility with BINARY Extension
Appendix C. Backward compatibility with LIST-EXTENDED extension 165 Appendix C. Backward Compatibility with LIST-EXTENDED Extension
Appendix D. 63 bit body part and message sizes . . . . . . . . . 165 Appendix D. 63-Bit Body Part and Message Sizes
Appendix E. Changes from RFC 3501 / IMAP4rev1 . . . . . . . . . 166 Appendix E. Changes from RFC 3501 / IMAP4rev1
Appendix F. Other Recommended IMAP Extensions . . . . . . . . . 168 Appendix F. Other Recommended IMAP Extensions
Appendix G. Acknowledgement . . . . . . . . . . . . . . . . . . 168 Acknowledgements
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 Index
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 174 Authors' Addresses
1. How to Read This Document 1. How to Read This Document
1.1. Organization of This Document 1.1. Organization of This Document
This document is written from the point of view of the implementor of This document is written from the point of view of the implementor of
an IMAP4rev2 client or server. Beyond the protocol overview in an IMAP4rev2 client or server. Beyond the protocol overview in
section 2, it is not optimized for someone trying to understand the Section 2, it is not optimized for someone trying to understand the
operation of the protocol. The material in sections 3 through 5 operation of the protocol. The material in Sections 3, 4, and 5
provides the general context and definitions with which IMAP4rev2 provides the general context and definitions with which IMAP4rev2
operates. operates.
Sections 6, 7, and 9 describe the IMAP commands, responses, and Sections 6, 7, and 9 describe the IMAP commands, responses, and
syntax, respectively. The relationships among these are such that it syntax, respectively. The relationships among these are such that it
is almost impossible to understand any of them separately. In is almost impossible to understand any of them separately. In
particular, do not attempt to deduce command syntax from the command particular, do not attempt to deduce command syntax from the command
section alone; instead refer to the Formal Syntax (Section 9). section alone; instead, refer to "Formal Syntax" (Section 9).
1.2. Conventions Used in This Document 1.2. Conventions Used in This Document
"Conventions" are basic principles or procedures. Document "Conventions" are basic principles or procedures. Document
conventions are noted in this section. conventions are noted in this section.
In examples, "C:" and "S:" indicate lines sent by the client and In examples, "C:" and "S:" indicate lines sent by the client and
server respectively. Note that each line includes the terminating server, respectively. Note that each line includes the terminating
CRLF. CRLF.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in
14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
The word "can" (not "may") is used to refer to a possible The word "can" (not "may") is used to refer to a possible
circumstance or situation, as opposed to an optional facility of the circumstance or situation, as opposed to an optional facility of the
protocol. protocol.
"User" is used to refer to a human user, whereas "client" refers to "User" is used to refer to a human user, whereas "client" refers to
the software being run by the user. the software being run by the user.
"Connection" refers to the entire sequence of client/server "Connection" refers to the entire sequence of client/server
skipping to change at page 6, line 24 skipping to change at line 254
until its termination. until its termination.
"Session" refers to the sequence of client/server interaction from "Session" refers to the sequence of client/server interaction from
the time that a mailbox is selected (SELECT or EXAMINE command) until the time that a mailbox is selected (SELECT or EXAMINE command) until
the time that selection ends (SELECT or EXAMINE of another mailbox, the time that selection ends (SELECT or EXAMINE of another mailbox,
CLOSE command, UNSELECT command, or connection termination). CLOSE command, UNSELECT command, or connection termination).
The term "Implicit TLS" refers to the automatic negotiation of TLS The term "Implicit TLS" refers to the automatic negotiation of TLS
whenever a TCP connection is made on a particular TCP port that is whenever a TCP connection is made on a particular TCP port that is
used exclusively by that server for TLS connections. The term used exclusively by that server for TLS connections. The term
"Implicit TLS" is intended to contrast with the use of STARTTLS "Implicit TLS" is intended to contrast with the use of the STARTTLS
command in IMAP that is used by the client and the server to command in IMAP that is used by the client and the server to
explicitly negotiate TLS on an established cleartext TCP connection. explicitly negotiate TLS on an established cleartext TCP connection.
Characters are 8-bit UTF-8 (of which 7-bit US-ASCII is a subset) Characters are 8-bit UTF-8 (of which 7-bit US-ASCII is a subset),
unless otherwise specified. Other character sets are indicated using unless otherwise specified. Other character sets are indicated using
a "CHARSET", as described in [MIME-IMT] and defined in [CHARSET]. a "CHARSET", as described in [MIME-IMT] and defined in [CHARSET].
CHARSETs have important additional semantics in addition to defining CHARSETs have important additional semantics in addition to defining
character set; refer to these documents for more detail. a character set; refer to these documents for more detail.
There are several protocol conventions in IMAP. These refer to There are several protocol conventions in IMAP. These refer to
aspects of the specification which are not strictly part of the IMAP aspects of the specification that are not strictly part of the IMAP
protocol, but reflect generally-accepted practice. Implementations protocol but reflect generally accepted practice. Implementations
need to be aware of these conventions, and avoid conflicts whether or need to be aware of these conventions, and avoid conflicts whether or
not they implement the convention. For example, "&" may not be used not they implement the convention. For example, "&" may not be used
as a hierarchy delimiter since it conflicts with the Mailbox as a hierarchy delimiter since it conflicts with the Mailbox
International Naming Convention, and other uses of "&" in mailbox International Naming Convention, and other uses of "&" in mailbox
names are impacted as well. names are impacted as well.
1.3. Special Notes to Implementors 1.3. Special Notes to Implementors
Implementors of the IMAP protocol are strongly encouraged to read the Implementors of the IMAP protocol are strongly encouraged to read the
IMAP implementation recommendations document [IMAP-IMPLEMENTATION] in IMAP implementation recommendations document [IMAP-IMPLEMENTATION] in
conjunction with this document, to help understand the intricacies of conjunction with this document, to help understand the intricacies of
this protocol and how best to build an interoperable product. this protocol and how best to build an interoperable product.
IMAP4rev2 is designed to be upwards compatible from the IMAP4rev1 IMAP4rev2 is designed to be upwards compatible from the IMAP4rev1
[RFC3501], the [IMAP2] and unpublished IMAP2bis [IMAP2BIS] protocols. [RFC3501], IMAP2 [IMAP2], and unpublished IMAP2bis [IMAP2BIS]
IMAP4rev2 is largely compatible with the IMAP4rev1 protocol described protocols. IMAP4rev2 is largely compatible with the IMAP4rev1
in RFC 3501 and the IMAP4 protocol described in RFC 1730; the protocol described in RFC 3501 and the IMAP4 protocol described in
exception being in certain facilities added in RFC 1730 and RFC 3501 [RFC1730]; the exception being in certain facilities added in
that proved problematic and were subsequently removed or replaced by [RFC1730] and [RFC3501] that proved problematic and were subsequently
better alternatives. In the course of the evolution of IMAP4rev2, removed or replaced by better alternatives. In the course of the
some aspects in the earlier protocols have become obsolete. Obsolete evolution of IMAP4rev2, some aspects in the earlier protocols have
commands, responses, and data formats which an IMAP4rev2 become obsolete. Obsolete commands, responses, and data formats that
implementation can encounter when used with an earlier implementation an IMAP4rev2 implementation can encounter when used with an earlier
are described in Appendix E, Appendix A and [IMAP-OBSOLETE]. implementation are described in Appendices A and E and
IMAP4rev2 supports 63bit body part and message sizes. IMAP4rev2 [IMAP-OBSOLETE]. IMAP4rev2 supports 63-bit body parts and message
compatibility with BINARY and LIST-EXTENDED IMAP extensions are sizes. IMAP4rev2 compatibility with BINARY and LIST-EXTENDED IMAP
described in Appendix B and Appendix C respectively. extensions are described in Appendices B and C, respectively.
Other compatibility issues with IMAP2bis, the most common variant of Other compatibility issues with IMAP2bis, the most common variant of
the earlier protocol, are discussed in [IMAP-COMPAT]. A full the earlier protocol, are discussed in [IMAP-COMPAT]. A full
discussion of compatibility issues with rare (and presumed extinct) discussion of compatibility issues with rare (and presumed extinct)
variants of [IMAP2] is in [IMAP-HISTORICAL]; this document is variants of [IMAP2] is in [IMAP-HISTORICAL]; this document is
primarily of historical interest. primarily of historical interest.
IMAP was originally developed for the older [RFC-822] standard, and IMAP was originally developed for the older [RFC822] standard, and as
as a consequence, "RFC822.SIZE" fetch item in IMAP incorporates a consequence, the "RFC822.SIZE" fetch item in IMAP incorporates
"RFC822" in its name. "RFC822" should be interpreted as a reference "RFC822" in its name. "RFC822" should be interpreted as a reference
to the updated [RFC-5322] standard. to the updated [RFC5322] standard.
IMAP4rev2 does not specify a means of posting mail; this function is
handled by a mail submission protocol such as the one specified in
[RFC6409].
2. Protocol Overview 2. Protocol Overview
2.1. Link Level 2.1. Link Level
The IMAP4rev2 protocol assumes a reliable data stream such as that The IMAP4rev2 protocol assumes a reliable data stream such as that
provided by TCP. When TCP is used, an IMAP4rev2 server listens on provided by TCP. When TCP is used, an IMAP4rev2 server listens on
port 143 (cleartext port) or port 993 (Implicit TLS port). port 143 (cleartext port) or port 993 (Implicit TLS port).
2.2. Commands and Responses 2.2. Commands and Responses
An IMAP4rev2 connection consists of the establishment of a client/ An IMAP4rev2 connection consists of the establishment of a client/
server network connection, an initial greeting from the server, and server network connection, an initial greeting from the server, and
client/server interactions. These client/server interactions consist client/server interactions. These client/server interactions consist
of a client command, server data, and a server completion result of a client command, server data, and a server completion result
response. response.
All interactions transmitted by client and server are in the form of All interactions transmitted by client and server are in the form of
lines, that is, strings that end with a CRLF. The protocol receiver lines, that is, strings that end with a CRLF. The protocol receiver
of an IMAP4rev2 client or server is either reading a line, or is of an IMAP4rev2 client or server is reading either a line or a
reading a sequence of octets with a known count followed by a line. sequence of octets with a known count followed by a line.
2.2.1. Client Protocol Sender and Server Protocol Receiver 2.2.1. Client Protocol Sender and Server Protocol Receiver
The client command begins an operation. Each client command is The client command begins an operation. Each client command is
prefixed with an identifier (typically a short alphanumeric string, prefixed with an identifier (typically a short alphanumeric string,
e.g., A0001, A0002, etc.) called a "tag". A different tag is e.g., A0001, A0002, etc.) called a "tag". A different tag is
generated by the client for each command. More formally: the client generated by the client for each command. More formally: the client
SHOULD generate a unique tag for every command, but a server MUST SHOULD generate a unique tag for every command, but a server MUST
accept tag reuse. accept tag reuse.
skipping to change at page 8, line 33 skipping to change at line 359
case, the server sends a command continuation request response if it case, the server sends a command continuation request response if it
is ready for the octets (if appropriate) and the remainder of the is ready for the octets (if appropriate) and the remainder of the
command. This response is prefixed with the token "+". command. This response is prefixed with the token "+".
Note: If, instead, the server detected an error in the command, it Note: If, instead, the server detected an error in the command, it
sends a BAD completion response with a tag matching the command sends a BAD completion response with a tag matching the command
(as described below) to reject the command and prevent the client (as described below) to reject the command and prevent the client
from sending any more of the command. from sending any more of the command.
It is also possible for the server to send a completion response It is also possible for the server to send a completion response
for some other command (if multiple commands are in progress), or for some other command (if multiple commands are in progress) or
untagged data. In either case, the command continuation request untagged data. In either case, the command continuation request
is still pending; the client takes the appropriate action for the is still pending; the client takes the appropriate action for the
response, and reads another response from the server. In all response and reads another response from the server. In all
cases, the client MUST send a complete command (including cases, the client MUST send a complete command (including
receiving all command continuation request responses and sending receiving all command continuation request responses and sending
command continuations for the command) before initiating a new command continuations for the command) before initiating a new
command. command.
The protocol receiver of an IMAP4rev2 server reads a command line The protocol receiver of an IMAP4rev2 server reads a command line
from the client, parses the command and its arguments, and transmits from the client, parses the command and its arguments, and transmits
server data and a server command completion result response. server data and a server command completion result response.
2.2.2. Server Protocol Sender and Client Protocol Receiver 2.2.2. Server Protocol Sender and Client Protocol Receiver
Data transmitted by the server to the client and status responses Data transmitted by the server to the client and status responses
that do not indicate command completion are prefixed with the token that do not indicate command completion are prefixed with the token
"*", and are called untagged responses. "*" and are called untagged responses.
Server data MAY be sent as a result of a client command, or MAY be Server data MAY be sent as a result of a client command or MAY be
sent unilaterally by the server. There is no syntactic difference sent unilaterally by the server. There is no syntactic difference
between server data that resulted from a specific command and server between server data that resulted from a specific command and server
data that were sent unilaterally. data that were sent unilaterally.
The server completion result response indicates the success or The server completion result response indicates the success or
failure of the operation. It is tagged with the same tag as the failure of the operation. It is tagged with the same tag as the
client command which began the operation. Thus, if more than one client command that began the operation. Thus, if more than one
command is in progress, the tag in a server completion response command is in progress, the tag in a server completion response
identifies the command to which the response applies. There are identifies the command to which the response applies. There are
three possible server completion responses: OK (indicating success), three possible server completion responses: OK (indicating success),
NO (indicating failure), or BAD (indicating a protocol error such as NO (indicating failure), or BAD (indicating a protocol error such as
unrecognized command or command syntax error). unrecognized command or command syntax error).
Servers SHOULD enforce the syntax outlined in this specification Servers SHOULD strictly enforce the syntax outlined in this
strictly. Any client command with a protocol syntax error, including specification. Any client command with a protocol syntax error,
(but not limited to) missing or extraneous spaces or arguments, including (but not limited to) missing or extraneous spaces or
SHOULD be rejected, and the client given a BAD server completion arguments, SHOULD be rejected and the client given a BAD server
response. completion response.
The protocol receiver of an IMAP4rev2 client reads a response line The protocol receiver of an IMAP4rev2 client reads a response line
from the server. It then takes action on the response based upon the from the server. It then takes action on the response based upon the
first token of the response, which can be a tag, a "*", or a "+". first token of the response, which can be a tag, a "*", or a "+".
A client MUST be prepared to accept any server response at all times. A client MUST be prepared to accept any server response at all times.
This includes server data that was not requested. Server data SHOULD This includes server data that was not requested. Server data SHOULD
be remembered (cached), so that the client can reference its be remembered (cached), so that the client can reference its
remembered copy rather than sending a command to the server to remembered copy rather than sending a command to the server to
request the data. In the case of certain server data, the data MUST request the data. In the case of certain server data, the data MUST
be remembered, as specified elsewhere in this document. be remembered, as specified elsewhere in this document.
This topic is discussed in greater detail in the Server Responses This topic is discussed in greater detail in "Server Responses" (see
section. Section 7).
2.3. Message Attributes 2.3. Message Attributes
In addition to message text, each message has several attributes In addition to message text, each message has several attributes
associated with it. These attributes can be retrieved individually associated with it. These attributes can be retrieved individually
or in conjunction with other attributes or message texts. or in conjunction with other attributes or message texts.
2.3.1. Message Numbers 2.3.1. Message Numbers
Messages in IMAP4rev2 are accessed by one of two numbers; the unique Messages in IMAP4rev2 are accessed by one of two numbers: the Unique
identifier (UID) or the message sequence number. Identifier (UID) or the message sequence number.
2.3.1.1. Unique Identifier (UID) Message Attribute 2.3.1.1. Unique Identifier (UID) Message Attribute
A UID is an unsigned non-zero 32-bit value assigned to each message, A UID is an unsigned non-zero 32-bit value assigned to each message,
which when used with the unique identifier validity value (see below) which when used with the unique identifier validity value (see below)
forms a 64-bit value that MUST NOT refer to any other message in the forms a 64-bit value that MUST NOT refer to any other message in the
mailbox or any subsequent mailbox with the same name forever. Unique mailbox or any subsequent mailbox with the same name forever. Unique
identifiers are assigned in a strictly ascending fashion in the identifiers are assigned in a strictly ascending fashion in the
mailbox; as each message is added to the mailbox it is assigned a mailbox; as each message is added to the mailbox, it is assigned a
higher UID than the message(s) which were added previously. Unlike higher UID than those of all message(s) that are already in the
message sequence numbers, unique identifiers are not necessarily mailbox. Unlike message sequence numbers, unique identifiers are not
contiguous. necessarily contiguous.
The unique identifier of a message MUST NOT change during the The unique identifier of a message MUST NOT change during the session
session, and SHOULD NOT change between sessions. Any change of and SHOULD NOT change between sessions. Any change of unique
unique identifiers between sessions MUST be detectable using the identifiers between sessions MUST be detectable using the UIDVALIDITY
UIDVALIDITY mechanism discussed below. Persistent unique identifiers mechanism discussed below. Persistent unique identifiers are
are required for a client to resynchronize its state from a previous required for a client to resynchronize its state from a previous
session with the server (e.g., disconnected or offline access clients session with the server (e.g., disconnected or offline access clients
[IMAP-MODEL]); this is discussed further in [IMAP-DISC]. [IMAP-MODEL]); this is discussed further in [IMAP-DISC].
Associated with every mailbox are two 32-bit unsigned non-zero values Associated with every mailbox are two 32-bit unsigned non-zero values
which aid in unique identifier handling: the next unique identifier that aid in unique identifier handling: the next unique identifier
value (UIDNEXT) and the unique identifier validity value value (UIDNEXT) and the unique identifier validity value
(UIDVALIDITY). (UIDVALIDITY).
The next unique identifier value is the predicted value that will be The next unique identifier value is the predicted value that will be
assigned to a new message in the mailbox. Unless the unique assigned to a new message in the mailbox. Unless the unique
identifier validity also changes (see below), the next unique identifier validity also changes (see below), the next unique
identifier value MUST have the following two characteristics. First, identifier value MUST have the following two characteristics. First,
the next unique identifier value MUST NOT change unless new messages the next unique identifier value MUST NOT change unless new messages
are added to the mailbox; and second, the next unique identifier are added to the mailbox; and second, the next unique identifier
value MUST change whenever new messages are added to the mailbox, value MUST change whenever new messages are added to the mailbox,
even if those new messages are subsequently expunged. even if those new messages are subsequently expunged.
Note: The next unique identifier value is intended to provide a | Note: The next unique identifier value is intended to provide a
means for a client to determine whether any messages have been | means for a client to determine whether any messages have been
delivered to the mailbox since the previous time it checked this | delivered to the mailbox since the previous time it checked
value. It is not intended to provide any guarantee that any | this value. It is not intended to provide any guarantee that
message will have this unique identifier. A client can only | any message will have this unique identifier. A client can
assume, at the time that it obtains the next unique identifier | only assume, at the time that it obtains the next unique
value, that messages arriving after that time will have a UID | identifier value, that messages arriving after that time will
greater than or equal to that value. | have a UID greater than or equal to that value.
The unique identifier validity value is sent in a UIDVALIDITY The unique identifier validity value is sent in a UIDVALIDITY
response code in an OK untagged response at mailbox selection time. response code in an OK untagged response at mailbox selection time.
If unique identifiers from an earlier session fail to persist in this If unique identifiers from an earlier session fail to persist in this
session, the unique identifier validity value MUST be greater than session, the unique identifier validity value MUST be greater than
the one used in the earlier session. A good UIDVALIDITY value to use the one used in the earlier session. A good UIDVALIDITY value to use
is a 32-bit representation of the current date/time when the value is is a 32-bit representation of the current date/time when the value is
assigned: this ensures that the value is unique and always increases. assigned: this ensures that the value is unique and always increases.
Another possible alternative is a global counter that gets Another possible alternative is a global counter that gets
incremented every time a mailbox is created. incremented every time a mailbox is created.
Note: Ideally, unique identifiers SHOULD persist at all times. Note: Ideally, unique identifiers SHOULD persist at all times.
Although this specification recognizes that failure to persist can Although this specification recognizes that failure to persist can
be unavoidable in certain server environments, it strongly be unavoidable in certain server environments, it strongly
encourages message store implementation techniques that avoid this encourages message store implementation techniques that avoid this
problem. For example: problem. For example:
1. Unique identifiers MUST be strictly ascending in the mailbox 1. Unique identifiers MUST be strictly ascending in the mailbox at
at all times. If the physical message store is re-ordered by all times. If the physical message store is reordered by a non-
a non-IMAP agent, this requires that the unique identifiers in IMAP agent, the unique identifiers in the mailbox MUST be
the mailbox be regenerated, since the former unique regenerated, since the former unique identifiers are no longer
identifiers are no longer strictly ascending as a result of strictly ascending as a result of the reordering.
the re-ordering.
2. If the message store has no mechanism to store unique 2. If the message store has no mechanism to store unique
identifiers, it must regenerate unique identifiers at each identifiers, it must regenerate unique identifiers at each
session, and each session must have a unique UIDVALIDITY session, and each session must have a unique UIDVALIDITY value.
value. Note that this situation can be very disruptive to client message
caching.
3. If the mailbox is deleted/renamed and a new mailbox with the 3. If the mailbox is deleted/renamed and a new mailbox with the same
same name is created at a later date, the server must either name is created at a later date, the server must either keep
keep track of unique identifiers from the previous instance of track of unique identifiers from the previous instance of the
the mailbox, or it must assign a new UIDVALIDITY value to the mailbox or assign a new UIDVALIDITY value to the new instance of
new instance of the mailbox. the mailbox.
4. The combination of mailbox name, UIDVALIDITY, and UID must 4. The combination of mailbox name, UIDVALIDITY, and UID must refer
refer to a single immutable (or expunged) message on that to a single, immutable (or expunged) message on that server
server forever. In particular, the internal date, [RFC-5322] forever. In particular, the internal date, RFC822.SIZE,
size, envelope, body structure, and message texts (all envelope, body structure, and message texts (all BODY[...] fetch
BODY[...] fetch data items) MUST never change. This does not data items) MUST never change. This does not include message
include message numbers, nor does it include attributes that numbers, nor does it include attributes that can be set by a
can be set by a STORE command (e.g., FLAGS). When a message STORE command (such as FLAGS). When a message is expunged, its
is expunged, its UID MUST NOT be reused under the same UID MUST NOT be reused under the same UIDVALIDITY value.
UIDVALIDITY value.
2.3.1.2. Message Sequence Number Message Attribute 2.3.1.2. Message Sequence Number Message Attribute
A Message Sequence Number is a relative position from 1 to the number A message sequence number is a relative position from 1 to the number
of messages in the mailbox. This position MUST be ordered by of messages in the mailbox. This position MUST be ordered by
ascending unique identifier. As each new message is added, it is ascending unique identifiers. As each new message is added, it is
assigned a message sequence number that is 1 higher than the number assigned a message sequence number that is 1 higher than the number
of messages in the mailbox before that new message was added. of messages in the mailbox before that new message was added.
Message sequence numbers can be reassigned during the session. For Message sequence numbers can be reassigned during the session. For
example, when a message is permanently removed (expunged) from the example, when a message is permanently removed (expunged) from the
mailbox, the message sequence number for all subsequent messages is mailbox, the message sequence number for all subsequent messages is
decremented. The number of messages in the mailbox is also decremented. The number of messages in the mailbox is also
decremented. Similarly, a new message can be assigned a message decremented. Similarly, a new message can be assigned a message
sequence number that was once held by some other message prior to an sequence number that was once held by some other message prior to an
expunge. expunge.
In addition to accessing messages by relative position in the In addition to accessing messages by relative position in the
mailbox, message sequence numbers can be used in mathematical mailbox, message sequence numbers can be used in mathematical
calculations. For example, if an untagged "11 EXISTS" is received, calculations. For example, if an untagged "11 EXISTS" is received,
and previously an untagged "8 EXISTS" was received, three new and previously an untagged "8 EXISTS" was received, three new
messages have arrived with message sequence numbers of 9, 10, and 11. messages have arrived with message sequence numbers of 9, 10, and 11.
Another example, if message 287 in a 523 message mailbox has UID As another example, if message 287 in a 523-message mailbox has UID
12345, there are exactly 286 messages which have lesser UIDs and 236 12345, there are exactly 286 messages that have lesser UIDs and 236
messages which have greater UIDs. messages that have greater UIDs.
2.3.2. Flags Message Attribute 2.3.2. Flags Message Attribute
A message has associated with it a list of zero or more named tokens, A message has a list of zero or more named tokens, known as "flags",
known as "flags". A flag is set by its addition to this list, and is associated with it. A flag is set by its addition to this list and
cleared by its removal. There are two types of flags in IMAP4rev2: is cleared by its removal. There are two types of flags in
system flags, and keywords. A flag of either type can also be IMAP4rev2: system flags and keywords. A flag of either type can be
permanent or session-only. permanent or session-only.
A system flag is a flag name that is pre-defined in this A system flag is a flag name that is predefined in this specification
specification and begins with "\". Certain system flags (\Deleted and begins with "\". Certain system flags (\Deleted and \Seen) have
and \Seen) have special semantics described elsewhere in this special semantics described elsewhere in this document. The
document. The currently-defined system flags are: currently defined system flags are:
\Seen Message has been read \Seen Message has been read
\Answered Message has been answered \Answered Message has been answered
\Flagged Message is "flagged" for urgent/special attention \Flagged Message is "flagged" for urgent/special attention
\Deleted Message is "deleted" for removal by later EXPUNGE \Deleted Message is "deleted" for removal by later EXPUNGE
\Draft Message has not completed composition (marked as a draft). \Draft Message has not completed composition (marked as a
draft).
\Recent This flag was in use in IMAP4rev1 and is now deprecated. \Recent This flag was in use in IMAP4rev1 and is now
deprecated.
A keyword is defined by the server implementation. Keywords do not A keyword is defined by the server implementation. Keywords do not
begin with "\". Servers MAY permit the client to define new keywords begin with "\". Servers MAY permit the client to define new keywords
in the mailbox (see the description of the PERMANENTFLAGS response in the mailbox (see the description of the PERMANENTFLAGS response
code for more information). Some keywords that start with "$" are code for more information). Some keywords that start with "$" are
also defined in this specification. also defined in this specification.
This document defines several keywords that were not originally This document defines several keywords that were not originally
defined in RFC 3501, but which were found to be useful by client defined in [RFC3501] but were found to be useful by client
implementations. These keywords SHOULD be supported (i.e. allowed in implementations. These keywords SHOULD be supported (allowed in
SEARCH, allowed and preserved in APPEND, COPY, MOVE commands) by SEARCH and allowed and preserved in APPEND, COPY, and MOVE commands)
server implementations: by server implementations:
$Forwarded Message has been forwarded to another email address, $Forwarded
embedded within or attached to a new message. An email client Message has been forwarded to another email address by being
embedded within, or attached to a new message. An email client
sets this keyword when it successfully forwards the message to sets this keyword when it successfully forwards the message to
another email address. Typical usage of this keyword is to show a another email address. Typical usage of this keyword is to show a
different (or additional) icon for a message that has been different (or additional) icon for a message that has been
forwarded. Once set, the flag SHOULD NOT be cleared. forwarded. Once set, the flag SHOULD NOT be cleared.
$MDNSent Message Disposition Notification [RFC8098] was generated $MDNSent
and sent for this message. See [RFC3503] for more details on how Message Disposition Notification [RFC8098] was generated and sent
this keyword is used and for requirements on clients and servers. for this message. See [RFC3503] for more details on how this
keyword is used and for requirements on clients and servers.
$Junk The user (or a delivery agent on behalf of the user) may $Junk
choose to mark a message as definitely containing junk ($Junk; see The user (or a delivery agent on behalf of the user) may choose to
also the related keyword $NotJunk). The $Junk keyword can be used mark a message as definitely containing junk ($Junk; see also the
to mark (and potentially move/delete messages later), group or related keyword $NotJunk). The $Junk keyword can be used to mark,
hide undesirable messages. See [IMAP-KEYWORDS-REG] for more group, or hide undesirable messages (and such messages might be
moved or deleted later). See [IMAP-KEYWORDS-REG] for more
information. information.
$NotJunk The user (or a delivery agent on behalf of the user) may $NotJunk
choose to mark a message as definitely not containing junk The user (or a delivery agent on behalf of the user) may choose to
($NotJunk; see also the related keyword $Junk). The $NotJunk mark a message as definitely not containing junk ($NotJunk; see
keyword can be used to mark, group or show messages that the user also the related keyword $Junk). The $NotJunk keyword can be used
wants to see. See [IMAP-KEYWORDS-REG] for more information. to mark, group, or show messages that the user wants to see. See
[IMAP-KEYWORDS-REG] for more information.
$Phishing
The $Phishing keyword can be used by a delivery agent to mark a
message as highly likely to be a phishing email. A message that's
determined to be a phishing email by the delivery agent should
also be considered a junk email and have the appropriate junk
filtering applied, including setting the $Junk flag and placing
the message in the \Junk special-use mailbox (see Section 7.3.1),
if available.
$Phishing The $Phishing keyword can be used by a delivery agent to
mark a message as highly likely to be a phishing email. An email
that's determined to be a phishing email by the delivery agent
should also be considered a junk email and have the appropriate
junk filtering applied, including setting the $Junk flag and
placing in the \Junk special-use mailbox (see Section 7.3.1) if
available.
If both the $Phishing flag and the $Junk flag are set, the user If both the $Phishing flag and the $Junk flag are set, the user
agent should display an additional warning message to the user. agent should display an additional warning message to the user.
Additionally the user agent may display a warning when clicking on Additionally, the user agent might display a warning, such as
any hyperlinks within the message. something of the form, "This message may be trying to steal your
personal information," when the user clicks on any hyperlinks
within the message.
The requirement for both $Phishing and $Junk to be set before a The requirement for both $Phishing and $Junk to be set before a
user agent displays a warning is for better backwards user agent displays a warning is for better backwards
compatibility with existing clients that understand the $Junk flag compatibility with existing clients that understand the $Junk flag
but not the $Phishing flag. This is so that when an unextended but not the $Phishing flag. This is so that when an unextended
client removes the $Junk flag, an extended client will also show client removes the $Junk flag, an extended client will also show
the correct state. See [IMAP-KEYWORDS-REG] for more information. the correct state. See [IMAP-KEYWORDS-REG] for more information.
$Junk and $NotJunk are mutually exclusive. If more than one of them $Junk and $NotJunk are mutually exclusive. If more than one of these
is set for a message, the client MUST treat this as if none of them is set for a message, the client MUST treat it as if none are set,
is set and SHOULD unset both of them on the IMAP server. and it SHOULD unset both of them on the IMAP server.
Other registered keywords can be found in the "IMAP and JMAP Other registered keywords can be found in the "IMAP and JMAP
Keywords" registry [IMAP-KEYWORDS-REG]. New keywords SHOULD be Keywords" registry [IMAP-KEYWORDS-REG]. New keywords SHOULD be
registered in this registry using the procedure specified in registered in this registry using the procedure specified in
[RFC5788]. [RFC5788].
A flag can be permanent or session-only on a per-flag basis. A flag can be permanent or session-only on a per-flag basis.
Permanent flags are those which the client can add or remove from the Permanent flags are those that the client can add or remove from the
message flags permanently; that is, concurrent and subsequent message flags permanently; that is, concurrent and subsequent
sessions will see any change in permanent flags. Changes to session sessions will see any change in permanent flags. Changes to session
flags are valid only in that session. flags are valid only in that session.
2.3.3. Internal Date Message Attribute 2.3.3. Internal Date Message Attribute
An Internal Date message attribute is the internal date and time of An Internal Date message attribute is the internal date and time of
the message on the server. This is not the date and time in the the message on the server. This is not the date and time in the
[RFC-5322] header, but rather a date and time which reflects when the [RFC5322] header but rather a date and time that reflects when the
message was received. In the case of messages delivered via [SMTP], message was received. In the case of messages delivered via [SMTP],
this is the date and time of final delivery of the message as defined this is the date and time of final delivery of the message as defined
by [SMTP]. In the case of messages delivered by the IMAP4rev2 COPY by [SMTP]. In the case of messages created by the IMAP4rev2 COPY or
or MOVE command, this SHOULD be the internal date and time of the MOVE command, this SHOULD be the same as the Internal Date attribute
source message. In the case of messages delivered by the IMAP4rev2 of the source message. In the case of messages created by the
APPEND command, this SHOULD be the date and time as specified in the IMAP4rev2 APPEND command, this SHOULD be the date and time as
APPEND command description. All other cases are implementation specified in the APPEND command description. All other cases are
defined. implementation defined.
2.3.4. [RFC-5322] Size Message Attribute 2.3.4. RFC822.SIZE Message Attribute
An RFC 5322 size is the number of octets in the message, as expressed RFC822.SIZE is the number of octets in the message when the message
in [RFC-5322] format. is expressed in [RFC5322] format. This size SHOULD match the result
of a "FETCH BODY[]" command. If the message is internally stored in
some other format, the server calculates the size and often stores it
for later use to avoid the need for recalculation.
2.3.5. Envelope Structure Message Attribute 2.3.5. Envelope Structure Message Attribute
An Envelope Structure is a parsed representation of the [RFC-5322] An envelope structure is a parsed representation of the [RFC5322]
header of the message. Note that the IMAP Envelope structure is not header of the message. Note that the IMAP envelope structure is not
the same as an [SMTP] envelope. the same as an [SMTP] envelope.
2.3.6. Body Structure Message Attribute 2.3.6. Body Structure Message Attribute
A Body Structure is a parsed representation of the [MIME-IMB] body A body structure is a parsed representation of the [MIME-IMB] body
structure information of the message. structure information of the message.
2.4. Message Texts 2.4. Message Texts
In addition to being able to fetch the full [RFC-5322] text of a In addition to being able to fetch the full [RFC5322] text of a
message, IMAP4rev2 permits the fetching of portions of the full message, IMAP4rev2 permits the fetching of portions of the full
message text. Specifically, it is possible to fetch the [RFC-5322] message text. Specifically, it is possible to fetch the [RFC5322]
message header, [RFC-5322] message body, a [MIME-IMB] body part, or a message header, the [RFC5322] message body, a [MIME-IMB] body part,
[MIME-IMB] header. or a [MIME-IMB] header.
3. State and Flow Diagram 3. State and Flow Diagram
Once the connection between client and server is established, an Once the connection between client and server is established, an
IMAP4rev2 connection is in one of four states. The initial state is IMAP4rev2 connection is in one of four states. The initial state is
identified in the server greeting. Most commands are only valid in identified in the server greeting. Most commands are only valid in
certain states. It is a protocol error for the client to attempt a certain states. It is a protocol error for the client to attempt a
command while the connection is in an inappropriate state, and the command while the connection is in an inappropriate state, and the
server will respond with a BAD or NO (depending upon server server will respond with a BAD or NO (depending upon server
implementation) command completion result. implementation) command completion result.
skipping to change at page 15, line 49 skipping to change at line 716
3.3. Selected State 3.3. Selected State
In a selected state, a mailbox has been selected to access. This In a selected state, a mailbox has been selected to access. This
state is entered when a mailbox has been successfully selected. state is entered when a mailbox has been successfully selected.
3.4. Logout State 3.4. Logout State
In the logout state, the connection is being terminated. This state In the logout state, the connection is being terminated. This state
can be entered as a result of a client request (via the LOGOUT can be entered as a result of a client request (via the LOGOUT
command) or by unilateral action on the part of either the client or command) or by unilateral action on the part of either the client or
server. the server.
If the client requests the logout state, the server MUST send an If the client requests the logout state, the server MUST send an
untagged BYE response and a tagged OK response to the LOGOUT command untagged BYE response and a tagged OK response to the LOGOUT command
before the server closes the connection; and the client MUST read the before the server closes the connection; and the client MUST read the
tagged OK response to the LOGOUT command before the client closes the tagged OK response to the LOGOUT command before the client closes the
connection. connection.
A server SHOULD NOT unilaterally close the connection without sending A server SHOULD NOT unilaterally close the connection without first
an untagged BYE response that contains the reason for having done so. sending an untagged BYE response that contains the reason for doing
A client SHOULD NOT unilaterally close the connection, and instead so. A client SHOULD NOT unilaterally close the connection; instead,
SHOULD issue a LOGOUT command. If the server detects that the client it SHOULD issue a LOGOUT command. If the server detects that the
has unilaterally closed the connection, the server MAY omit the client has unilaterally closed the connection, the server MAY omit
untagged BYE response and simply close its connection. the untagged BYE response and simply close its connection.
+----------------------+ +----------------------+
|connection established| |connection established|
+----------------------+ +----------------------+
|| ||
\/ \/
+--------------------------------------+ +--------------------------------------+
| server greeting | | server greeting |
+--------------------------------------+ +--------------------------------------+
|| (1) || (2) || (3) || (1) || (2) || (3)
skipping to change at page 17, line 39 skipping to change at line 765
\/ \/ \/ \/ \/ \/ \/ \/
+--------------------------------------+ +--------------------------------------+
| Logout | | Logout |
+--------------------------------------+ +--------------------------------------+
|| ||
\/ \/
+-------------------------------+ +-------------------------------+
|both sides close the connection| |both sides close the connection|
+-------------------------------+ +-------------------------------+
(1) connection without pre-authentication (OK greeting) Legend for the above diagram:
(2) pre-authenticated connection (PREAUTH greeting)
(3) rejected connection (BYE greeting) (1) connection without pre-authentication (OK greeting)
(4) successful LOGIN or AUTHENTICATE command (2) pre-authenticated connection (PREAUTH greeting)
(5) successful SELECT or EXAMINE command (3) rejected connection (BYE greeting)
(6) CLOSE or UNSELECT command, unsolicited CLOSED (4) successful LOGIN or AUTHENTICATE command
response code or failed SELECT or EXAMINE command (5) successful SELECT or EXAMINE command
(7) LOGOUT command, server shutdown, or connection closed (6) CLOSE or UNSELECT command, unsolicited CLOSED response code, or
failed SELECT or EXAMINE command
(7) LOGOUT command, server shutdown, or connection closed
4. Data Formats 4. Data Formats
IMAP4rev2 uses textual commands and responses. Data in IMAP4rev2 can IMAP4rev2 uses textual commands and responses. Data in IMAP4rev2 can
be in one of several forms: atom, number, string, parenthesized list, be in one of several forms: atom, number, string, parenthesized list,
or NIL. Note that a particular data item may take more than one or NIL. Note that a particular data item may take more than one
form; for example, a data item defined as using "astring" syntax may form; for example, a data item defined as using "astring" syntax may
be either an atom or a string. be either an atom or a string.
4.1. Atom 4.1. Atom
An atom consists of one or more non-special characters. An atom consists of one or more non-special characters.
4.1.1. Sequence set and UID set 4.1.1. Sequence Set and UID Set
A set of messages can be referenced by a sequence set containing A set of messages can be referenced by a sequence set containing
either message sequence numbers or unique identifiers. See Section 9 either message sequence numbers or unique identifiers. See Section 9
for details. Sequence sets can contain ranges (e.g. "5:50"), an for details. A sequence set can contain ranges of sequence numbers
enumeration of specific message sequence numbers/unique identifiers, (such as "5:50"), an enumeration of specific sequence numbers, or a
a special symbol "*", or a combination of the above. Note that a combination of the above. A sequence set can use the special symbol
sequence set never mixes message sequence numbers and unique "*" to represent the maximum sequence number in the mailbox. A
identifiers in the same representation. sequence set never contains unique identifiers.
A "UID set" is similar to the sequence set of unique identifiers; A "UID set" is similar to the sequence set, but uses unique
however, the "*" value for a sequence number is not permitted. identifiers instead of message sequence numbers, and is not permitted
to contain the special symbol "*".
4.2. Number 4.2. Number
A number consists of one or more digit characters, and represents a A number consists of one or more digit characters and represents a
numeric value. numeric value.
4.3. String 4.3. String
A string is in one of three forms: synchronizing literal, non- A string is in one of three forms: synchronizing literal, non-
synchronizing literal or quoted string. The synchronizing literal synchronizing literal, or quoted string. The synchronizing literal
form is the general form of string. The non-synchronizing literal form is the general form of a string, without limitation on the
form is also the general form, but has length limitation. The quoted characters the string may include. The non-synchronizing literal
string form is an alternative that avoids the overhead of processing form is also the general form, but it has a length restriction. The
a literal at the cost of limitations of characters which may be used. quoted string form is an alternative that avoids the overhead of
processing a literal, but has limitations on the characters that may
be used.
When the distinction between synchronizing and non-synchronizing When the distinction between synchronizing and non-synchronizing
literals is not important, this document only uses the term literals is not important, this document only uses the term
"literal". "literal".
A synchronizing literal is a sequence of zero or more octets A synchronizing literal is a sequence of zero or more octets
(including CR and LF), prefix-quoted with an octet count in the form (including CR and LF), prefix-quoted with an octet count in the form
of an open brace ("{"), the number of octets, close brace ("}"), and of an open brace ("{"), the number of octets, a close brace ("}"),
CRLF. In the case of synchronizing literals transmitted from server and a CRLF. In the case of synchronizing literals transmitted from
to client, the CRLF is immediately followed by the octet data. In server to client, the CRLF is immediately followed by the octet data.
the case of synchronizing literals transmitted from client to server, In the case of synchronizing literals transmitted from client to
the client MUST wait to receive a command continuation request server, the client MUST wait to receive a command continuation
(described later in this document) before sending the octet data (and request (described later in this document) before sending the octet
the remainder of the command). data (and the remainder of the command).
The non-synchronizing literal is an alternative form of synchronizing The non-synchronizing literal is an alternative form of synchronizing
literal, and it may appear in communication from client to server literal and may be used from client to server anywhere a
instead of the synchonizing form of literal. The non-synchronizing synchronizing literal is permitted. The non-synchronizing literal
literal form MUST NOT be sent from server to client. The non- form MUST NOT be sent from server to client. The non-synchronizing
synchronizing literal is distinguished from the synchronizing literal literal is distinguished from the synchronizing literal by having a
by having a plus ("+") between the octet count and the closing brace plus ("+") between the octet count and the closing brace ("}"). The
("}"). The server does not generate a command continuation request server does not generate a command continuation request in response
in response to a non-synchronizing literal, and clients are not to a non-synchronizing literal, and clients are not required to wait
required to wait before sending the octets of a non- synchronizing before sending the octets of a non-synchronizing literal. Unless
literal. Unless specified otherwise in an IMAP extension, non- otherwise specified in an IMAP extension, non-synchronizing literals
synchronizing literals MUST NOT be larger than 4096 octets. Any MUST NOT be larger than 4096 octets. Any literal larger than 4096
literal larger than 4096 bytes MUST be sent as a synchronizing bytes MUST be sent as a synchronizing literal. (Non-synchronizing
literal. (Non-synchronizing literals defined in this document are literals defined in this document are the same as non-synchronizing
the same as non-synchronizing literals defined by the LITERAL- literals defined by the LITERAL- extension from [RFC7888]. See that
extension from [RFC7888]. See that document for details on how to document for details on how to handle invalid non-synchronizing
handle invalid non-synchronizing literals longer than 4096 octets and literals longer than 4096 octets and for interaction with other IMAP
for interaction with other IMAP extensions.) extensions.)
A quoted string is a sequence of zero or more Unicode characters, A quoted string is a sequence of zero or more Unicode characters,
excluding CR and LF, encoded in UTF-8, with double quote (<">) excluding CR and LF, encoded in UTF-8, with double quote (<">)
characters at each end. characters at each end.
The empty string is represented as "" (a quoted string with zero The empty string is represented as "" (a quoted string with zero
characters between double quotes), as {0} followed by CRLF (a characters between double quotes), as {0} followed by a CRLF (a
synchronizing literal with an octet count of 0) or as {0+} followed synchronizing literal with an octet count of 0), or as {0+} followed
by CRLF (a non-synchronizing literal with an octet count of 0). by a CRLF (a non-synchronizing literal with an octet count of 0).
Note: Even if the octet count is 0, a client transmitting a Note: Even if the octet count is 0, a client transmitting a
synchronizing literal MUST wait to receive a command continuation synchronizing literal MUST wait to receive a command continuation
request. request.
4.3.1. 8-bit and Binary Strings 4.3.1. 8-Bit and Binary Strings
8-bit textual and binary mail is supported through the use of a 8-bit textual and binary mail is supported through the use of a
[MIME-IMB] content transfer encoding. IMAP4rev2 implementations MAY [MIME-IMB] content transfer encoding. IMAP4rev2 implementations MAY
transmit 8-bit or multi-octet characters in literals, but SHOULD do transmit 8-bit or multi-octet characters in literals but SHOULD do so
so only when the [CHARSET] is identified. only when the [CHARSET] is identified.
IMAP4rev2 is compatible with [I18N-HDRS]. As a result, the IMAP4rev2 is compatible with [I18N-HDRS]. As a result, the
identified charset for header-field values with 8-bit content is identified charset for header-field values with 8-bit content is
UTF-8 [UTF-8]. IMAP4rev2 implementations MUST accept and MAY UTF-8 [UTF-8]. IMAP4rev2 implementations MUST accept and MAY
transmit [UTF-8] text in quoted-strings as long as the string does transmit [UTF-8] text in quoted-strings as long as the string does
not contain NUL, CR, or LF. This differs from IMAP4rev1 not contain NUL, CR, or LF. This differs from IMAP4rev1
implementations. implementations.
Although a BINARY content transfer encoding is defined, unencoded Although a BINARY content transfer encoding is defined, unencoded
binary strings are not permitted, unless returned in a <literal8> in binary strings are not permitted, unless returned in a <literal8> in
response to BINARY.PEEK[<section-binary>]<<partial>> or response to a BINARY.PEEK[<section-binary>]<<partial>> or
BINARY[<section-binary>]<<partial>> FETCH data item. A "binary BINARY[<section-binary>]<<partial>> FETCH data item. A "binary
string" is any string with NUL characters. A string with an string" is any string with NUL characters. A string with an
excessive amount of CTL characters MAY also be considered to be excessive amount of CTL characters MAY also be considered to be
binary. Unless returned in response to BINARY.PEEK[...]/BINARY[...] binary. Unless returned in response to BINARY.PEEK[...]/BINARY[...]
FETCH, client and server implementations MUST encode binary data into FETCH, client and server implementations MUST encode binary data into
a textual form, such as BASE64, before transmitting the data. a textual form, such as base64, before transmitting the data.
4.4. Parenthesized List 4.4. Parenthesized List
Data structures are represented as a "parenthesized list"; a sequence Data structures are represented as a "parenthesized list"; a sequence
of data items, delimited by space, and bounded at each end by of data items, delimited by space, and bounded at each end by
parentheses. A parenthesized list can contain other parenthesized parentheses. A parenthesized list can contain other parenthesized
lists, using multiple levels of parentheses to indicate nesting. lists, using multiple levels of parentheses to indicate nesting.
The empty list is represented as () -- a parenthesized list with no The empty list is represented as () -- a parenthesized list with no
members. members.
4.5. NIL 4.5. NIL
The special form "NIL" represents the non-existence of a particular The special form "NIL" represents the non-existence of a particular
data item that is represented as a string or parenthesized list, as data item that is represented as a string or parenthesized list, as
distinct from the empty string "" or the empty parenthesized list (). distinct from the empty string "" or the empty parenthesized list ().
Note: NIL is never used for any data item which takes the form of | Note: NIL is never used for any data item that takes the form
an atom. For example, a mailbox name of "NIL" is a mailbox named | of an atom. For example, a mailbox name of "NIL" is a mailbox
NIL as opposed to a non-existent mailbox name. This is because | named NIL as opposed to a non-existent mailbox name. This is
mailbox uses "astring" syntax which is an atom or a string. | because mailbox uses "astring" syntax, which is an atom or a
Conversely, an addr-name of NIL is a non-existent personal name, | string. Conversely, an addr-name of NIL is a non-existent
because addr-name uses "nstring" syntax which is NIL or a string, | personal name, because addr-name uses "nstring" syntax, which
but never an atom. | is NIL or a string, but never an atom.
Examples: Examples:
The following LIST response: The following LIST response:
* LIST () "/" NIL * LIST () "/" NIL
is equivalent to: is equivalent to:
* LIST () "/" "NIL" * LIST () "/" "NIL"
as LIST response ABNF is using "astring" for mailbox name. as LIST response ABNF is using "astring" for mailbox name.
However, the following response However, the following response:
* FETCH 1 (BODY[1] NIL) * FETCH 1 (BODY[1] NIL)
is not equivalent to: is not equivalent to:
* FETCH 1 (BODY[1] "NIL") * FETCH 1 (BODY[1] "NIL")
The former means absence of the body part, while the latter The former indicates absence of the body part, while the latter means
means that it contains literal sequence of characters "NIL". that it contains a string with the three characters "NIL".
5. Operational Considerations 5. Operational Considerations
The following rules are listed here to ensure that all IMAP4rev2 The following rules are listed here to ensure that all IMAP4rev2
implementations interoperate properly. implementations interoperate properly.
5.1. Mailbox Naming 5.1. Mailbox Naming
In IMAP4rev2, Mailbox names are encoded in Net-Unicode [NET-UNICODE] In IMAP4rev2, mailbox names are encoded in Net-Unicode [NET-UNICODE]
(this differs from IMAP4rev1). Client implementations MAY attempt to (this differs from IMAP4rev1). Client implementations MAY attempt to
create Net-Unicode mailbox names, and MUST interpret any 8-bit create Net-Unicode mailbox names and MUST interpret any 8-bit mailbox
mailbox names returned by LIST as [NET-UNICODE]. Server names returned by LIST as [NET-UNICODE]. Server implementations MUST
implementations MUST prohibit the creation of 8-bit mailbox names prohibit the creation of 8-bit mailbox names that do not comply with
that do not comply with Net-Unicode. However, servers MAY accept a Net-Unicode. However, servers MAY accept a denormalized UTF-8
de-normalized UTF-8 mailbox name and convert it to Unicode mailbox name and convert it to Unicode Normalization Form C (NFC) (as
normalization form "NFC" (as per Net-Unicode requirements) prior to per Net-Unicode requirements) prior to mailbox creation. Servers
mailbox creation. Servers that choose to accept such de-normalized that choose to accept such denormalized UTF-8 mailbox names MUST
UTF-8 mailbox names MUST accept them in all IMAP commands that have a accept them in all IMAP commands that have a mailbox name parameter.
mailbox name parameter. In particular SELECT <name> must open the In particular, SELECT <name> must open the same mailbox that was
same mailbox that was successfully created with CREATE <name>, even successfully created with CREATE <name>, even if <name> is a
if <name> is a de-normalized UTF-8 mailbox name. denormalized UTF-8 mailbox name.
The case-insensitive mailbox name INBOX is a special name reserved to The case-insensitive mailbox name INBOX is a special name reserved to
mean "the primary mailbox for this user on this server". (Note that mean "the primary mailbox for this user on this server". (Note that
this special name may not exist on some servers for some users, for this special name might not exist on some servers for some users, for
example if the user has no access to personal namespace.) The example, if the user has no access to personal namespace.) The
interpretation of all other names is implementation-dependent. interpretation of all other names is implementation dependent.
In particular, this specification takes no position on case In particular, this specification takes no position on case
sensitivity in non-INBOX mailbox names. Some server implementations sensitivity in non-INBOX mailbox names. Some server implementations
are fully case-sensitive in ASCII range; others preserve case of a are fully case sensitive in ASCII range; others preserve the case of
newly-created name but otherwise are case-insensitive; and yet others a newly created name but otherwise are case insensitive; and yet
coerce names to a particular case. Client implementations must be others coerce names to a particular case. Client implementations
able to interact with any of these. must be able to interact with any of these.
There are certain client considerations when creating a new mailbox There are certain client considerations when creating a new mailbox
name: name:
1. Any character which is one of the atom-specials (see the Formal 1. Any character that is one of the atom-specials (see "Formal
Syntax in Section 9) will require that the mailbox name be Syntax" in Section 9) will require that the mailbox name be
represented as a quoted string or literal. represented as a quoted string or literal.
2. CTL and other non-graphic characters are difficult to represent 2. CTL and other non-graphic characters are difficult to represent
in a user interface and are best avoided. Servers MAY refuse to in a user interface and are best avoided. Servers MAY refuse to
create mailbox names containing Unicode CTL characters. create mailbox names containing Unicode CTL characters.
3. Although the list-wildcard characters ("%" and "*") are valid in 3. Although the list-wildcard characters ("%" and "*") are valid in
a mailbox name, it is difficult to use such mailbox names with a mailbox name, it is difficult to use such mailbox names with
the LIST command due to the conflict with wildcard the LIST command due to the conflict with wildcard
interpretation. interpretation.
4. Usually, a character (determined by the server implementation) is 4. Usually, a character (determined by the server implementation) is
reserved to delimit levels of hierarchy. reserved to delimit levels of hierarchy.
5. Two characters, "#" and "&", have meanings by convention, and 5. Two characters, "#" and "&", have meanings by convention and
should be avoided except when used in that convention. See should be avoided except when used in that convention. See
Section 5.1.2.1 and Appendix A.1 respectively. Section 5.1.2.1 and Appendix A.1, respectively.
5.1.1. Mailbox Hierarchy Naming 5.1.1. Mailbox Hierarchy Naming
If it is desired to export hierarchical mailbox names, mailbox names If it is desired to export hierarchical mailbox names, mailbox names
MUST be left-to-right hierarchical using a single character to MUST be left-to-right hierarchical, using a single ASCII character to
separate levels of hierarchy. The same hierarchy separator character separate levels of hierarchy. The same hierarchy separator character
is used for all levels of hierarchy within a single name. is used for all levels of hierarchy within a single name.
5.1.2. Namespaces 5.1.2. Namespaces
Personal Namespace: A namespace that the server considers within the Personal Namespace:
personal scope of the authenticated user on a particular connection. A namespace that the server considers within the personal scope of
Typically, only the authenticated user has access to mailboxes in the authenticated user on a particular connection. Typically,
their Personal Namespace. It is the part of the namespace that only the authenticated user has access to mailboxes in their
belongs to the user that is allocated for mailboxes. If an INBOX Personal Namespace. It is the part of the namespace that belongs
exists for a user, it MUST appear within the user's personal to the user and is allocated for mailboxes. If an INBOX exists
namespace. In the typical case, there SHOULD be only one Personal for a user, it MUST appear within the user's Personal Namespace.
Namespace per user on a server. In the typical case, there SHOULD be only one Personal Namespace
per user on a server.
Other Users' Namespace: A namespace that consists of mailboxes from Other Users' Namespace:
the Personal Namespaces of other users. To access mailboxes in the A namespace that consists of mailboxes from the Personal
Other Users' Namespace, the currently authenticated user MUST be Namespaces of other users. To access mailboxes in the Other
explicitly granted access rights. For example, it is common for a Users' Namespace, the currently authenticated user MUST be
manager to grant to their administrative support staff access rights explicitly granted access rights. For example, it is common for a
to their mailbox. In the typical case, there SHOULD be only one manager to grant to their administrative support staff access
Other Users' Namespace per user on a server. rights to their mailbox. In the typical case, there SHOULD be
only one Other Users' Namespace per user on a server.
Shared Namespace: A namespace that consists of mailboxes that are Shared Namespace:
intended to be shared amongst users and do not exist within a user's A namespace that consists of mailboxes that are intended to be
Personal Namespace. shared amongst users and do not exist within a user's Personal
Namespace.
The namespaces a server uses MAY differ on a per-user basis. The namespaces a server uses MAY differ on a per-user basis.
5.1.2.1. Historic Mailbox Namespace Naming Convention 5.1.2.1. Historic Mailbox Namespace Naming Convention
By convention, the first hierarchical element of any mailbox name By convention, the first hierarchical element of any mailbox name
which begins with "#" identifies the "namespace" of the remainder of that begins with "#" identifies the "namespace" of the remainder of
the name. This makes it possible to disambiguate between different the name. This makes it possible to disambiguate between different
types of mailbox stores, each of which have their own namespaces. types of mailbox stores, each of which have their own namespaces.
For example, implementations which offer access to USENET For example, implementations that offer access to USENET
newsgroups MAY use the "#news" namespace to partition the USENET newsgroups MAY use the "#news" namespace to partition the USENET
newsgroup namespace from that of other mailboxes. Thus, the newsgroup namespace from that of other mailboxes. Thus, the
comp.mail.misc newsgroup would have a mailbox name of comp.mail.misc newsgroup would have a mailbox name of
"#news.comp.mail.misc", and the name "comp.mail.misc" can refer to "#news.comp.mail.misc", and the name "comp.mail.misc" can refer to
a different object (e.g., a user's private mailbox). a different object (e.g., a user's private mailbox).
Namespaces that include the "#" character are not IMAP URL [IMAP-URL] Namespaces that include the "#" character are not IMAP URL [IMAP-URL]
friendly requiring the "#" character to be represented as %23 when friendly and require the "#" character to be represented as %23 when
within URLs. As such, server implementors MAY instead consider using within URLs. As such, server implementors MAY instead consider using
namespace prefixes that do not contain the "#" character. namespace prefixes that do not contain the "#" character.
5.1.2.2. Common namespace models 5.1.2.2. Common Namespace Models
The previous version of this protocol did not define a default server The previous version of this protocol did not define a default server
namespace. Two common namespace models have evolved: namespace. Two common namespace models have evolved:
The "Personal Mailbox" model, in which the default namespace that is The "Personal Mailbox" model, in which the default namespace that is
presented consists of only the user's personal mailboxes. To access presented consists of only the user's personal mailboxes. To access
shared mailboxes, the user must use an escape mechanism to reach shared mailboxes, the user must use an escape mechanism to reach
another namespace. another namespace.
The "Complete Hierarchy" model, in which the default namespace that The "Complete Hierarchy" model, in which the default namespace that
is presented includes the user's personal mailboxes along with any is presented includes the user's personal mailboxes along with any
other mailboxes they have access to. other mailboxes they have access to.
5.2. Mailbox Size and Message Status Updates 5.2. Mailbox Size and Message Status Updates
At any time, a server can send data that the client did not request. At any time, a server can send data that the client did not request.
Sometimes, such behavior is required by this specification and/or Sometimes, such behavior is required by this specification and/or
extensions. For example, agents other than the server MAY add extensions. For example, agents other than the server may add
messages to the mailbox (e.g., new message delivery), change the messages to the mailbox (e.g., new message delivery); change the
flags of the messages in the mailbox (e.g., simultaneous access to flags of the messages in the mailbox (e.g., simultaneous access to
the same mailbox by multiple agents), or even remove messages from the same mailbox by multiple agents); or even remove messages from
the mailbox. A server MUST send mailbox size updates automatically the mailbox. A server MUST send mailbox size updates automatically
if a mailbox size change is observed during the processing of a if a mailbox size change is observed during the processing of a
command. A server SHOULD send message flag updates automatically, command. A server SHOULD send message flag updates automatically,
without requiring the client to request such updates explicitly. without requiring the client to request such updates explicitly.
Special rules exist for server notification of a client about the Special rules exist for server notification of a client about the
removal of messages to prevent synchronization errors; see the removal of messages to prevent synchronization errors; see the
description of the EXPUNGE response (Section 7.5.1) for more detail. description of the EXPUNGE response (Section 7.5.1) for more detail.
In particular, it is NOT permitted to send an EXISTS response that In particular, it is NOT permitted to send an EXISTS response that
would reduce the number of messages in the mailbox; only the EXPUNGE would reduce the number of messages in the mailbox; only the EXPUNGE
response can do this. response can do this.
Regardless of what implementation decisions a client makes on Regardless of what implementation decisions a client makes on
remembering data from the server, a client implementation MUST remembering data from the server, a client implementation MUST
remember mailbox size updates. It MUST NOT assume that any command remember mailbox size updates. It MUST NOT assume that any command
after the initial mailbox selection will return the size of the after the initial mailbox selection will return the size of the
mailbox. mailbox.
5.3. Response when no Command in Progress 5.3. Response When No Command in Progress
Server implementations are permitted to send an untagged response Server implementations are permitted to send an untagged response
(except for EXPUNGE) while there is no command in progress. Server (except for EXPUNGE) while there is no command in progress. Server
implementations that send such responses MUST deal with flow control implementations that send such responses MUST deal with flow control
considerations. Specifically, they MUST either (1) verify that the considerations. Specifically, they MUST either (1) verify that the
size of the data does not exceed the underlying transport's available size of the data does not exceed the underlying transport's available
window size, or (2) use non-blocking writes. window size or (2) use non-blocking writes.
5.4. Autologout Timer 5.4. Autologout Timer
If a server has an inactivity autologout timer that applies to If a server has an inactivity autologout timer that applies to
sessions after authentication, the duration of that timer MUST be at sessions after authentication, the duration of that timer MUST be at
least 30 minutes. The receipt of any command from the client during least 30 minutes. The receipt of any command from the client during
that interval resets the autologout timer. that interval resets the autologout timer.
Note that this specification doesn't have any restrictions on Note that this specification doesn't have any restrictions on an
autologout timer used before successful client authentication. In autologout timer used before successful client authentication. In
particular, servers are allowed to use shortened pre-authentication particular, servers are allowed to use a shortened pre-authentication
timer to protect themselves from Denial of Service attacks. timer to protect themselves from Denial-of-Service attacks.
5.5. Multiple Commands in Progress (Command Pipelining) 5.5. Multiple Commands in Progress (Command Pipelining)
The client MAY send another command without waiting for the The client MAY send another command without waiting for the
completion result response of a command, subject to ambiguity rules completion result response of a command, subject to ambiguity rules
(see below) and flow control constraints on the underlying data (see below) and flow control constraints on the underlying data
stream. Similarly, a server MAY begin processing another command stream. Similarly, a server MAY begin processing another command
before processing the current command to completion, subject to before processing the current command to completion, subject to
ambiguity rules. However, any command continuation request responses ambiguity rules. However, any command continuation request responses
and command continuations MUST be negotiated before any subsequent and command continuations MUST be negotiated before any subsequent
command is initiated. command is initiated.
The exception is if an ambiguity would result because of a command The exception is if an ambiguity would result because of a command
that would affect the results of other commands. If the server that would affect the results of other commands. If the server
detects a possible ambiguity, it MUST execute commands to completion detects a possible ambiguity, it MUST execute commands to completion
in the order given by the client. in the order given by the client.
The most obvious example of ambiguity is when a command would affect The most obvious example of ambiguity is when a command would affect
the results of another command, e.g., a FETCH of a message's flags the results of another command. One example is a FETCH that would
and a STORE of that same message's flags. cause \Seen flags to be set and a SEARCH UNSEEN command.
A non-obvious ambiguity occurs with commands that permit an untagged A non-obvious ambiguity occurs with commands that permit an untagged
EXPUNGE response (commands other than FETCH, STORE, and SEARCH), EXPUNGE response (commands other than FETCH, STORE, and SEARCH),
since an untagged EXPUNGE response can invalidate sequence numbers in since an untagged EXPUNGE response can invalidate sequence numbers in
a subsequent command. This is not a problem for FETCH, STORE, or a subsequent command. This is not a problem for FETCH, STORE, or
SEARCH commands because servers are prohibited from sending EXPUNGE SEARCH commands because servers are prohibited from sending EXPUNGE
responses while any of those commands are in progress. Therefore, if responses while any of those commands are in progress. Therefore, if
the client sends any command other than FETCH, STORE, or SEARCH, it the client sends any command other than FETCH, STORE, or SEARCH, it
MUST wait for the completion result response before sending a command MUST wait for the completion result response before sending a command
with message sequence numbers. with message sequence numbers.
Note: EXPUNGE responses are permitted while UID FETCH, UID STORE, Note: EXPUNGE responses are permitted while UID FETCH, UID STORE,
and UID SEARCH are in progress. If the client sends a UID and UID SEARCH are in progress. If the client sends a UID
command, it MUST wait for a completion result response before command, it MUST wait for a completion result response before
sending a command which uses message sequence numbers (this may sending a command that uses message sequence numbers (this may
include UID SEARCH). Any message sequence numbers in an argument include UID SEARCH). Any message sequence numbers in an argument
to UID SEARCH are associated with messages prior to the effect of to UID SEARCH are associated with messages prior to the effect of
any untagged EXPUNGE returned by the UID SEARCH. any untagged EXPUNGE responses returned by the UID SEARCH.
For example, the following non-waiting command sequences are invalid: For example, the following non-waiting command sequences are invalid:
FETCH + NOOP + STORE FETCH + NOOP + STORE
STORE + COPY + FETCH STORE + COPY + FETCH
COPY + COPY COPY + COPY
The following are examples of valid non-waiting command sequences: The following are examples of valid non-waiting command sequences:
FETCH + STORE + SEARCH + NOOP FETCH + STORE + SEARCH + NOOP
STORE + COPY + EXPUNGE STORE + COPY + EXPUNGE
UID SEARCH + UID SEARCH may be valid or invalid as a non-waiting UID SEARCH + UID SEARCH may be valid or invalid as a non-waiting
command sequence, depending upon whether or not the second UID command sequence, depending upon whether or not the second UID SEARCH
SEARCH contains message sequence numbers. contains message sequence numbers.
Use of SEARCH result variable (see Section 6.4.4.1) creates direct Use of a SEARCH result variable (see Section 6.4.4.1) creates direct
dependency between two commands. See Section 6.4.4.2 for more dependency between two commands. See Section 6.4.4.2 for more
considerations about pipelining such dependent commands. considerations about pipelining such dependent commands.
6. Client Commands 6. Client Commands
IMAP4rev2 commands are described in this section. Commands are IMAP4rev2 commands are described in this section. Commands are
organized by the state in which the command is permitted. Commands organized by the state in which the command is permitted. Commands
which are permitted in multiple states are listed in the minimum that are permitted in multiple states are listed in the minimum
permitted state (for example, commands valid in authenticated and permitted state (for example, commands valid in authenticated and
selected state are listed in the authenticated state commands). selected states are listed in the authenticated state commands).
Command arguments, identified by "Arguments:" in the command Command arguments, identified by "Arguments:" in the command
descriptions below, are described by function, not by syntax. The descriptions below, are described by function, not by syntax. The
precise syntax of command arguments is described in the Formal Syntax precise syntax of command arguments is described in "Formal Syntax"
(Section 9). (Section 9).
Some commands cause specific server responses to be returned; these Some commands cause specific server responses to be returned; these
are identified by "Responses:" in the command descriptions below. are identified by "Responses:" in the command descriptions below.
See the response descriptions in the Responses section (Section 7) See the response descriptions in "Responses" (Section 7) for
for information on these responses, and the Formal Syntax (Section 9) information on these responses and in "Formal Syntax" (Section 9) for
for the precise syntax of these responses. It is possible for server the precise syntax of these responses. It is possible for server
data to be transmitted as a result of any command. Thus, commands data to be transmitted as a result of any command. Thus, commands
that do not specifically require server data specify "no specific that do not specifically require server data specify "no specific
responses for this command" instead of "none". responses for this command" instead of "none".
The "Result:" in the command description refers to the possible The "Result:" in the command description refers to the possible
tagged status responses to a command, and any special interpretation tagged status responses to a command and any special interpretation
of these status responses. of these status responses.
The state of a connection is only changed by successful commands The state of a connection is only changed by successful commands that
which are documented as changing state. A rejected command (BAD are documented as changing state. A rejected command (BAD response)
response) never changes the state of the connection or of the never changes the state of the connection or of the selected mailbox.
selected mailbox. A failed command (NO response) generally does not A failed command (NO response) generally does not change the state of
change the state of the connection or of the selected mailbox; the the connection or of the selected mailbox, with the exception of the
exception being the SELECT and EXAMINE commands. SELECT and EXAMINE commands.
6.1. Client Commands - Any State 6.1. Client Commands - Any State
The following commands are valid in any state: CAPABILITY, NOOP, and The following commands are valid in any state: CAPABILITY, NOOP, and
LOGOUT. LOGOUT.
6.1.1. CAPABILITY Command 6.1.1. CAPABILITY Command
Arguments: none Arguments: none
Responses: REQUIRED untagged response: CAPABILITY Responses: REQUIRED untagged response: CAPABILITY
Result: OK - capability completed Result: OK - capability completed
BAD - arguments invalid BAD - arguments invalid
The CAPABILITY command requests a listing of capabilities (e.g. The CAPABILITY command requests a listing of capabilities (e.g.,
extensions and/or modifications of server behaviour) that the server extensions and/or modifications of server behavior) that the server
supports. The server MUST send a single untagged CAPABILITY response supports. The server MUST send a single untagged CAPABILITY response
with "IMAP4rev2" as one of the listed capabilities before the with "IMAP4rev2" as one of the listed capabilities before the
(tagged) OK response. (tagged) OK response.
A capability name which begins with "AUTH=" indicates that the server A capability name that begins with "AUTH=" indicates that the server
supports that particular authentication mechanism as defined in supports that particular authentication mechanism as defined in the
[SASL]. All such names are, by definition, part of this Simple Authentication and Security Layer (SASL) [SASL]. All such
specification. names are, by definition, part of this specification.
Other capability names refer to extensions, revisions, or amendments Other capability names refer to extensions, revisions, or amendments
to this specification. See the documentation of the CAPABILITY to this specification. See the documentation of the CAPABILITY
response in Section 7.2.2 for additional information. If IMAP4rev1 response in Section 7.2.2 for additional information. If IMAP4rev1
capability is not advertised, no capabilities, beyond the base capability is not advertised, no capabilities, beyond the base
IMAP4rev2 set defined in this specification, are enabled without IMAP4rev2 set defined in this specification, are enabled without
explicit client action to invoke the capability. If both IMAP4rev1 explicit client action to invoke the capability. If both IMAP4rev1
and IMAP4rev2 capabilities are advertised, no capabilities, beyond and IMAP4rev2 capabilities are advertised, no capabilities, beyond
the base IMAP4rev1 set specified in RFC 3501, are enabled without the base IMAP4rev1 set specified in [RFC3501], are enabled without
explicit client action to invoke the capability. explicit client action to invoke the capability.
Client and server implementations MUST implement the STARTTLS Client and server implementations MUST implement the STARTTLS
Section 6.2.1 and LOGINDISABLED capabilities on cleartext ports. (Section 6.2.1) and LOGINDISABLED capabilities on cleartext ports.
Client and server implementations MUST also implement AUTH=PLAIN Client and server implementations MUST also implement AUTH=PLAIN
(described in [PLAIN]) capability on both cleartext and Implicit TLS (described in [PLAIN]) capability on both cleartext and Implicit TLS
ports. See the Security Considerations (Section 11) for important ports. See the Security Considerations (Section 11) for important
information. information.
Unless specified otherwise, all registered extensions to IMAP4rev1 Unless otherwise specified, all registered extensions to IMAP4rev1
are also valid extensions to IMAP4rev2. are also valid extensions to IMAP4rev2.
Example: C: abcd CAPABILITY Example:
S: * CAPABILITY IMAP4rev2 STARTTLS AUTH=GSSAPI
LOGINDISABLED C: abcd CAPABILITY
S: abcd OK CAPABILITY completed S: * CAPABILITY IMAP4rev2 STARTTLS AUTH=GSSAPI
C: efgh STARTTLS LOGINDISABLED
S: efgh OK STARTLS completed S: abcd OK CAPABILITY completed
<TLS negotiation, further commands are under [TLS] layer> C: efgh STARTTLS
C: ijkl CAPABILITY S: efgh OK STARTTLS completed
S: * CAPABILITY IMAP4rev2 AUTH=GSSAPI AUTH=PLAIN <TLS negotiation, further commands are under TLS layer>
S: ijkl OK CAPABILITY completed C: ijkl CAPABILITY
S: * CAPABILITY IMAP4rev2 AUTH=GSSAPI AUTH=PLAIN
S: ijkl OK CAPABILITY completed
6.1.2. NOOP Command 6.1.2. NOOP Command
Arguments: none Arguments: none
Responses: no specific responses for this command (but see below) Responses: no specific responses for this command (but see below)
Result: OK - noop completed Result: OK - noop completed
BAD - command unknown or arguments invalid BAD - command unknown or arguments invalid
The NOOP command always succeeds. It does nothing. The NOOP command always succeeds. It does nothing.
Since any command can return a status update as untagged data, the Since any command can return a status update as untagged data, the
NOOP command can be used as a periodic poll for new messages or NOOP command can be used as a periodic poll for new messages or
message status updates during a period of inactivity (the IDLE message status updates during a period of inactivity (the IDLE
command Section 6.3.13 should be used instead of NOOP if real-time command; see Section 6.3.13) should be used instead of NOOP if real-
updates to mailbox state are desirable). The NOOP command can also time updates to mailbox state are desirable). The NOOP command can
be used to reset any inactivity autologout timer on the server. also be used to reset any inactivity autologout timer on the server.
Example: C: a002 NOOP Example:
S: a002 OK NOOP completed
. . . C: a002 NOOP
C: a047 NOOP S: a002 OK NOOP completed
S: * 22 EXPUNGE . . .
S: * 23 EXISTS C: a047 NOOP
S: * 14 FETCH (UID 1305 FLAGS (\Seen \Deleted)) S: * 22 EXPUNGE
S: a047 OK NOOP completed S: * 23 EXISTS
S: * 14 FETCH (UID 1305 FLAGS (\Seen \Deleted))
S: a047 OK NOOP completed
6.1.3. LOGOUT Command 6.1.3. LOGOUT Command
Arguments: none Arguments: none
Responses: REQUIRED untagged response: BYE Responses: REQUIRED untagged response: BYE
Result: OK - logout completed Result: OK - logout completed
BAD - command unknown or arguments invalid BAD - command unknown or arguments invalid
The LOGOUT command informs the server that the client is done with The LOGOUT command informs the server that the client is done with
the connection. The server MUST send a BYE untagged response before the connection. The server MUST send a BYE untagged response before
the (tagged) OK response, and then close the network connection. the (tagged) OK response, and then close the network connection.
Example: C: A023 LOGOUT Example:
S: * BYE IMAP4rev2 Server logging out
S: A023 OK LOGOUT completed C: A023 LOGOUT
(Server and client then close the connection) S: * BYE IMAP4rev2 Server logging out
S: A023 OK LOGOUT completed
(Server and client then close the connection)
6.2. Client Commands - Not Authenticated State 6.2. Client Commands - Not Authenticated State
In the not authenticated state, the AUTHENTICATE or LOGIN command In the not authenticated state, the AUTHENTICATE or LOGIN command
establishes authentication and enters the authenticated state. The establishes authentication and enters the authenticated state. The
AUTHENTICATE command provides a general mechanism for a variety of AUTHENTICATE command provides a general mechanism for a variety of
authentication techniques, privacy protection, and integrity authentication techniques, privacy protection, and integrity
checking; whereas the LOGIN command uses a traditional user name and checking, whereas the LOGIN command uses a conventional user name and
plaintext password pair and has no means of establishing privacy plaintext password pair and has no means of establishing privacy
protection or integrity checking. protection or integrity checking.
The STARTTLS command is an alternative form of establishing session The STARTTLS command is an alternative form of establishing session
privacy protection and integrity checking, but does not by itself privacy protection and integrity checking but does not by itself
establish authentication or enter the authenticated state. establish authentication or enter the authenticated state.
Server implementations MAY allow access to certain mailboxes without Server implementations MAY allow access to certain mailboxes without
establishing authentication. This can be done by means of the establishing authentication. This can be done by means of the
ANONYMOUS [SASL] authenticator described in [ANONYMOUS]. An older ANONYMOUS [SASL] authenticator described in [ANONYMOUS]. An older
convention is a LOGIN command using the userid "anonymous"; in this convention is a LOGIN command using the userid "anonymous"; in this
case, a password is required although the server may choose to accept case, a password is required although the server may choose to accept
any password. The restrictions placed on anonymous users are any password. The restrictions placed on anonymous users are
implementation-dependent. implementation dependent.
Once authenticated (including as anonymous), it is not possible to Once authenticated (including as anonymous), it is not possible to
re-enter not authenticated state. re-enter not authenticated state.
In addition to the universal commands (CAPABILITY, NOOP, and LOGOUT), In addition to the universal commands (CAPABILITY, NOOP, and LOGOUT),
the following commands are valid in the not authenticated state: the following commands are valid in the not authenticated state:
STARTTLS, AUTHENTICATE and LOGIN. See the Security Considerations STARTTLS, AUTHENTICATE, and LOGIN. See the Security Considerations
(Section 11) for important information about these commands. (Section 11) for important information about these commands.
6.2.1. STARTTLS Command 6.2.1. STARTTLS Command
Arguments: none Arguments: none
Responses: no specific response for this command Responses: no specific response for this command
Result: OK - starttls completed, begin TLS negotiation Result: OK - starttls completed, begin TLS negotiation
NO - TLS negotiation can't be initiated, due to server NO - TLS negotiation can't be initiated, due to server
configuration error configuration error
BAD - STARTTLS received after a successful TLS BAD - STARTTLS received after a successful TLS
negotiation or arguments invalid negotiation or arguments invalid
Note that STARTTLS command is available only on cleartext ports. The Note that the STARTTLS command is available only on cleartext ports.
server MUST always respond with tagged BAD response when STARTTLS The server MUST always respond with a tagged BAD response when the
command is received on Implicit TLS port. STARTTLS command is received on an Implicit TLS port.
A TLS [TLS-1.3] negotiation begins immediately after the CRLF at the A TLS [TLS-1.3] negotiation begins immediately after the CRLF at the
end of the tagged OK response from the server. Once a client issues end of the tagged OK response from the server. Once a client issues
a STARTTLS command, it MUST NOT issue further commands until a server a STARTTLS command, it MUST NOT issue further commands until a server
response is seen and the TLS negotiation is complete. Some past response is seen and the TLS negotiation is complete. Some past
server implementation incorrectly implemented STARTTLS processing and server implementations incorrectly implemented STARTTLS processing
are known to contain STARTTLS plaintext command injection and are known to contain STARTTLS plaintext command injection
vulnerability [CERT-555316]. In order to avoid this vulnerability, vulnerability [CERT-555316]. In order to avoid this vulnerability,
server implementations MUST do one of the following If any data is server implementations MUST do one of the following if any data is
received in the same TCP buffer after the CRLF that starts the received in the same TCP buffer after the CRLF that starts the
STARTTLS command: STARTTLS command:
1. Extra data from the TCP buffer is interpreted as beginning of the 1. Extra data from the TCP buffer is interpreted as the beginning of
TLS handshake. (If the data is in cleartext, this will result in the TLS handshake. (If the data is in cleartext, this will
the TLS handshake failing.) result in the TLS handshake failing.)
2. Extra data from the TCP buffer is thrown away. 2. Extra data from the TCP buffer is thrown away.
Note that the first option is friendlier to clients that pipeline Note that the first option is friendlier to clients that pipeline the
beginning of STARTTLS command with TLS handshake data. beginning of the STARTTLS command with TLS handshake data.
After successful TLS negotiation the server remains in the non- After successful TLS negotiation, the server remains in the non-
authenticated state, even if client credentials are supplied during authenticated state, even if client credentials are supplied during
the TLS negotiation. This does not preclude an authentication the TLS negotiation. This does not preclude an authentication
mechanism such as EXTERNAL (defined in [SASL]) from using client mechanism such as EXTERNAL (defined in [SASL]) from using client
identity determined by the TLS negotiation. identity determined by the TLS negotiation.
Once TLS has been started, the client MUST discard cached information Once TLS has been started, the client MUST discard cached information
about server capabilities and SHOULD re-issue the CAPABILITY command. about server capabilities and SHOULD reissue the CAPABILITY command.
This is necessary to protect against man-in- the-middle attacks which This is necessary to protect against active attacks that alter the
alter the capabilities list prior to STARTTLS. The server MAY capabilities list prior to STARTTLS. The server MAY advertise
advertise different capabilities, and in particular SHOULD NOT different capabilities and, in particular, SHOULD NOT advertise the
advertise the STARTTLS capability, after a successful STARTTLS STARTTLS capability, after a successful STARTTLS command.
command.
Example: C: a001 CAPABILITY Example:
S: * CAPABILITY IMAP4rev2 STARTTLS LOGINDISABLED
S: a001 OK CAPABILITY completed C: a001 CAPABILITY
C: a002 STARTTLS S: * CAPABILITY IMAP4rev2 STARTTLS LOGINDISABLED
S: a002 OK Begin TLS negotiation now S: a001 OK CAPABILITY completed
<TLS negotiation, further commands are under TLS layer> C: a002 STARTTLS
C: a003 CAPABILITY S: a002 OK Begin TLS negotiation now
S: * CAPABILITY IMAP4rev2 AUTH=PLAIN <TLS negotiation, further commands are under TLS layer>
S: a003 OK CAPABILITY completed C: a003 CAPABILITY
C: a004 AUTHENTICATE PLAIN dGVzdAB0ZXN0AHRlc3Q= S: * CAPABILITY IMAP4rev2 AUTH=PLAIN
S: a004 OK Success (tls protection) S: a003 OK CAPABILITY completed
C: a004 AUTHENTICATE PLAIN dGVzdAB0ZXN0AHRlc3Q=
S: a004 OK Success (tls protection)
6.2.2. AUTHENTICATE Command 6.2.2. AUTHENTICATE Command
Arguments: SASL authentication mechanism name Arguments: SASL authentication mechanism name
OPTIONAL initial response
Responses: continuation data can be requested OPTIONAL initial response
Result: OK - authenticate completed, now in authenticated state Responses: continuation data can be requested
NO - authenticate failure: unsupported authentication
mechanism, credentials rejected Result: OK - authenticate completed, now in authenticated
BAD - command unknown or arguments invalid, state
authentication exchange cancelled NO - authenticate failure: unsupported authentication
mechanism, credentials rejected
BAD - command unknown or arguments invalid,
authentication exchange canceled
The AUTHENTICATE command indicates a [SASL] authentication mechanism The AUTHENTICATE command indicates a [SASL] authentication mechanism
to the server. If the server supports the requested authentication to the server. If the server supports the requested authentication
mechanism, it performs an authentication protocol exchange to mechanism, it performs an authentication protocol exchange to
authenticate and identify the client. It MAY also negotiate an authenticate and identify the client. It MAY also negotiate an
OPTIONAL security layer for subsequent protocol interactions. If the OPTIONAL security layer for subsequent protocol interactions. If the
requested authentication mechanism is not supported, the server requested authentication mechanism is not supported, the server
SHOULD reject the AUTHENTICATE command by sending a tagged NO SHOULD reject the AUTHENTICATE command by sending a tagged NO
response. response.
The AUTHENTICATE command supports the optional "initial response" The AUTHENTICATE command supports the optional "initial response"
feature defined in Section 5.1 of [SASL]. The client doesn't need to feature defined in Section 4 of [SASL]. The client doesn't need to
use it. If a SASL mechanism supports "initial response", but it is use it. If a SASL mechanism supports "initial response", but it is
not specified by the client, the server handles this as specified in not specified by the client, the server handles it as specified in
Section 3 of [SASL]. Section 3 of [SASL].
The service name specified by this protocol's profile of [SASL] is The service name specified by this protocol's profile of [SASL] is
"imap". "imap".
The authentication protocol exchange consists of a series of server The authentication protocol exchange consists of a series of server
challenges and client responses that are specific to the challenges and client responses that are specific to the
authentication mechanism. A server challenge consists of a command authentication mechanism. A server challenge consists of a command
continuation request response with the "+" token followed by a BASE64 continuation request response with the "+" token followed by a
encoded (see Section 4 of [RFC4648]) string. The client response base64-encoded (see Section 4 of [RFC4648]) string. The client
consists of a single line consisting of a BASE64 encoded string. If response consists of a single line consisting of a base64-encoded
the client wishes to cancel an authentication exchange, it issues a string. If the client wishes to cancel an authentication exchange,
line consisting of a single "*". If the server receives such a it issues a line consisting of a single "*". If the server receives
response, or if it receives an invalid BASE64 string (e.g. such a response, or if it receives an invalid base64 string (e.g.,
characters outside the BASE64 alphabet, or non-terminal "="), it MUST characters outside the base64 alphabet or non-terminal "="), it MUST
reject the AUTHENTICATE command by sending a tagged BAD response. reject the AUTHENTICATE command by sending a tagged BAD response.
As with any other client response, the initial response MUST be As with any other client response, the initial response MUST be
encoded as BASE64. It also MUST be transmitted outside of a quoted encoded as base64. It also MUST be transmitted outside of a quoted
string or literal. To send a zero-length initial response, the string or literal. To send a zero-length initial response, the
client MUST send a single pad character ("="). This indicates that client MUST send a single pad character ("="). This indicates that
the response is present, but is a zero-length string. the response is present, but it is a zero-length string.
When decoding the BASE64 data in the initial response, decoding When decoding the base64 data in the initial response, decoding
errors MUST be treated as in any normal SASL client response, i.e. errors MUST be treated as in any normal SASL client response, i.e.,
with a tagged BAD response. In particular, the server should check with a tagged BAD response. In particular, the server should check
for any characters not explicitly allowed by the BASE64 alphabet, as for any characters not explicitly allowed by the base64 alphabet, as
well as any sequence of BASE64 characters that contains the pad well as any sequence of base64 characters that contains the pad
character ('=') anywhere other than the end of the string (e.g., character ('=') anywhere other than the end of the string (e.g.,
"=AAA" and "AAA=BBB" are not allowed). "=AAA" and "AAA=BBB" are not allowed).
If the client uses an initial response with a SASL mechanism that If the client uses an initial response with a SASL mechanism that
does not support an initial response, the server MUST reject the does not support an initial response, the server MUST reject the
command with a tagged BAD response. command with a tagged BAD response.
If a security layer is negotiated through the [SASL] authentication If a security layer is negotiated through the [SASL] authentication
exchange, it takes effect immediately following the CRLF that exchange, it takes effect immediately following the CRLF that
concludes the authentication exchange for the client, and the CRLF of concludes the authentication exchange for the client and the CRLF of
the tagged OK response for the server. the tagged OK response for the server.
While client and server implementations MUST implement the While client and server implementations MUST implement the
AUTHENTICATE command itself, it is not required to implement any AUTHENTICATE command itself, it is not required to implement any
authentication mechanisms other than the PLAIN mechanism described in authentication mechanisms other than the PLAIN mechanism described in
[PLAIN]. Also, an authentication mechanism is not required to [PLAIN]. Also, an authentication mechanism is not required to
support any security layers. support any security layers.
Note: a server implementation MUST implement a configuration in Note: a server implementation MUST implement a configuration in
which it does NOT permit any plaintext password mechanisms, unless which it does NOT permit any plaintext password mechanisms, unless
either the STARTTLS command has been negotiated, TLS has been the STARTTLS command has been negotiated, TLS has been negotiated
negotiated on an Implicit TLS port, or some other mechanism that on an Implicit TLS port, or some other mechanism that protects the
protects the session from password snooping has been provided. session from password snooping has been provided. Server sites
Server sites SHOULD NOT use any configuration which permits a SHOULD NOT use any configuration that permits a plaintext password
plaintext password mechanism without such a protection mechanism mechanism without such a protection mechanism against password
against password snooping. Client and server implementations snooping. Client and server implementations SHOULD implement
SHOULD implement additional [SASL] mechanisms that do not use additional [SASL] mechanisms that do not use plaintext passwords,
plaintext passwords, such the GSSAPI mechanism described in such as the GSSAPI mechanism described in [RFC4752], the SCRAM-
[RFC4752], the SCRAM-SHA-256/SCRAM-SHA-256-PLUS [SCRAM-SHA-256] SHA-256/SCRAM-SHA-256-PLUS [SCRAM-SHA-256] mechanisms, and/or the
mechanisms and/or EXTERNAL [SASL] mechanism for mutual TLS EXTERNAL [SASL] mechanism for mutual TLS authentication. (Note
authentication. (Note that SASL framework allows creation of SASL that the SASL framework allows for the creation of SASL mechanisms
mechanisms that support 2FA (2-factor authentication), however that support 2-factor authentication (2FA); however, none are
none are fully ready to be recommended by this document.) fully ready to be recommended by this document.)
Servers and clients can support multiple authentication mechanisms. Servers and clients can support multiple authentication mechanisms.
The server SHOULD list its supported authentication mechanisms in the The server SHOULD list its supported authentication mechanisms in the
response to the CAPABILITY command so that the client knows which response to the CAPABILITY command so that the client knows which
authentication mechanisms to use. authentication mechanisms to use.
A server MAY include a CAPABILITY response code in the tagged OK A server MAY include a CAPABILITY response code in the tagged OK
response of a successful AUTHENTICATE command in order to send response of a successful AUTHENTICATE command in order to send
capabilities automatically. It is unnecessary for a client to send a capabilities automatically. It is unnecessary for a client to send a
separate CAPABILITY command if it recognizes these automatic separate CAPABILITY command if it recognizes these automatic
skipping to change at page 34, line 5 skipping to change at line 1516
try another authentication mechanism by issuing another AUTHENTICATE try another authentication mechanism by issuing another AUTHENTICATE
command. It MAY also attempt to authenticate by using the LOGIN command. It MAY also attempt to authenticate by using the LOGIN
command (see Section 6.2.3 for more detail). In other words, the command (see Section 6.2.3 for more detail). In other words, the
client MAY request authentication types in decreasing order of client MAY request authentication types in decreasing order of
preference, with the LOGIN command as a last resort. preference, with the LOGIN command as a last resort.
The authorization identity passed from the client to the server The authorization identity passed from the client to the server
during the authentication exchange is interpreted by the server as during the authentication exchange is interpreted by the server as
the user name whose privileges the client is requesting. the user name whose privileges the client is requesting.
Example: S: * OK [CAPABILITY IMAP4rev2 STARTTLS AUTH=GSSAPI] Example:
Capabilities
C: A001 AUTHENTICATE GSSAPI
S: +
C: YIIB+wYJKoZIhvcSAQICAQBuggHqMIIB5qADAgEFoQMCAQ6iBw
MFACAAAACjggEmYYIBIjCCAR6gAwIBBaESGxB1Lndhc2hpbmd0
b24uZWR1oi0wK6ADAgEDoSQwIhsEaW1hcBsac2hpdmFtcy5jYW
Mud2FzaGluZ3Rvbi5lZHWjgdMwgdCgAwIBAaEDAgEDooHDBIHA
cS1GSa5b+fXnPZNmXB9SjL8Ollj2SKyb+3S0iXMljen/jNkpJX
AleKTz6BQPzj8duz8EtoOuNfKgweViyn/9B9bccy1uuAE2HI0y
C/PHXNNU9ZrBziJ8Lm0tTNc98kUpjXnHZhsMcz5Mx2GR6dGknb
I0iaGcRerMUsWOuBmKKKRmVMMdR9T3EZdpqsBd7jZCNMWotjhi
vd5zovQlFqQ2Wjc2+y46vKP/iXxWIuQJuDiisyXF0Y8+5GTpAL
pHDc1/pIGmMIGjoAMCAQGigZsEgZg2on5mSuxoDHEA1w9bcW9n
FdFxDKpdrQhVGVRDIzcCMCTzvUboqb5KjY1NJKJsfjRQiBYBdE
NKfzK+g5DlV8nrw81uOcP8NOQCLR5XkoMHC0Dr/80ziQzbNqhx
O6652Npft0LQwJvenwDI13YxpwOdMXzkWZN/XrEqOWp6GCgXTB
vCyLWLlWnbaUkZdEYbKHBPjd8t/1x5Yg==
S: + YGgGCSqGSIb3EgECAgIAb1kwV6ADAgEFoQMCAQ+iSzBJoAMC
AQGiQgRAtHTEuOP2BXb9sBYFR4SJlDZxmg39IxmRBOhXRKdDA0
uHTCOT9Bq3OsUTXUlk0CsFLoa8j+gvGDlgHuqzWHPSQg==
C:
S: + YDMGCSqGSIb3EgECAgIBAAD/////6jcyG4GE3KkTzBeBiVHe
ceP2CWY0SR0fAQAgAAQEBAQ=
C: YDMGCSqGSIb3EgECAgIBAAD/////3LQBHXTpFfZgrejpLlLImP
wkhbfa2QteAQAgAG1yYwE=
S: A001 OK GSSAPI authentication successful
The following example demonstrates use of initial response S: * OK [CAPABILITY IMAP4rev2 STARTTLS AUTH=GSSAPI]
Capabilities
C: A001 AUTHENTICATE GSSAPI
S: +
C: YIIB+wYJKoZIhvcSAQICAQBuggHqMIIB5qADAgEFoQMCAQ6iBw
MFACAAAACjggEmYYIBIjCCAR6gAwIBBaESGxB1Lndhc2hpbmd0
b24uZWR1oi0wK6ADAgEDoSQwIhsEaW1hcBsac2hpdmFtcy5jYW
Mud2FzaGluZ3Rvbi5lZHWjgdMwgdCgAwIBAaEDAgEDooHDBIHA
cS1GSa5b+fXnPZNmXB9SjL8Ollj2SKyb+3S0iXMljen/jNkpJX
AleKTz6BQPzj8duz8EtoOuNfKgweViyn/9B9bccy1uuAE2HI0y
C/PHXNNU9ZrBziJ8Lm0tTNc98kUpjXnHZhsMcz5Mx2GR6dGknb
I0iaGcRerMUsWOuBmKKKRmVMMdR9T3EZdpqsBd7jZCNMWotjhi
vd5zovQlFqQ2Wjc2+y46vKP/iXxWIuQJuDiisyXF0Y8+5GTpAL
pHDc1/pIGmMIGjoAMCAQGigZsEgZg2on5mSuxoDHEA1w9bcW9n
FdFxDKpdrQhVGVRDIzcCMCTzvUboqb5KjY1NJKJsfjRQiBYBdE
NKfzK+g5DlV8nrw81uOcP8NOQCLR5XkoMHC0Dr/80ziQzbNqhx
O6652Npft0LQwJvenwDI13YxpwOdMXzkWZN/XrEqOWp6GCgXTB
vCyLWLlWnbaUkZdEYbKHBPjd8t/1x5Yg==
S: + YGgGCSqGSIb3EgECAgIAb1kwV6ADAgEFoQMCAQ+iSzBJoAMC
AQGiQgRAtHTEuOP2BXb9sBYFR4SJlDZxmg39IxmRBOhXRKdDA0
uHTCOT9Bq3OsUTXUlk0CsFLoa8j+gvGDlgHuqzWHPSQg==
C:
S: + YDMGCSqGSIb3EgECAgIBAAD/////6jcyG4GE3KkTzBeBiVHe
ceP2CWY0SR0fAQAgAAQEBAQ=
C: YDMGCSqGSIb3EgECAgIBAAD/////3LQBHXTpFfZgrejpLlLImP
wkhbfa2QteAQAgAG1yYwE=
S: A001 OK GSSAPI authentication successful
The following example demonstrates the use of an initial response.
Example: Example:
S: * OK [CAPABILITY IMAP4rev2 STARTTLS AUTH=GSSAPI
LOGINDISABLED] Server ready S: * OK [CAPABILITY IMAP4rev2 STARTTLS AUTH=GSSAPI
C: A01 STARTTLS LOGINDISABLED] Server ready
S: A01 OK STARTLS completed C: A01 STARTTLS
<TLS negotiation, further commands are under [TLS] layer> S: A01 OK STARTTLS completed
C: A02 CAPABILITY <TLS negotiation, further commands are under TLS layer>
S: * CAPABILITY IMAP4rev2 AUTH=GSSAPI AUTH=PLAIN C: A02 CAPABILITY
S: A02 OK CAPABILITY completed S: * CAPABILITY IMAP4rev2 AUTH=GSSAPI AUTH=PLAIN
C: A03 AUTHENTICATE PLAIN dGVzdAB0ZXN0AHRlc3Q= S: A02 OK CAPABILITY completed
S: A03 OK Success (tls protection) C: A03 AUTHENTICATE PLAIN dGVzdAB0ZXN0AHRlc3Q=
S: A03 OK Success (tls protection)
Note that because the initial response is optional, the following
negotiation (which does not use the initial response) is still valid
and MUST be supported by the server:
... client connects to server and negotiates a TLS
protection layer ...
C: C01 CAPABILITY
S: * CAPABILITY IMAP4rev2 AUTH=PLAIN
S: C01 OK Completed
C: A01 AUTHENTICATE PLAIN
S: +
C: dGVzdAB0ZXN0AHRlc3Q=
S: A01 OK Success (tls protection)
Note that in the above example there is a space following the "+"
from the server.
The following is an example authentication using the SASL EXTERNAL
mechanism (defined in [SASL]) under a TLS protection layer and an
empty initial response:
... client connects to server and negotiates a TLS
protection layer ...
C: C01 CAPABILITY
S: * CAPABILITY IMAP4rev2 AUTH=PLAIN AUTH=EXTERNAL
S: C01 OK Completed
C: A01 AUTHENTICATE EXTERNAL =
S: A01 OK Success (tls protection)
Note: The line breaks within server challenges and client responses Note: The line breaks within server challenges and client responses
are for editorial clarity and are not in real authenticators. are for editorial clarity and are not in real authenticators.
6.2.3. LOGIN Command 6.2.3. LOGIN Command
Arguments: user name Arguments: user name
password
Responses: no specific responses for this command password
Result: OK - login completed, now in authenticated state Responses: no specific responses for this command
NO - login failure: user name or password rejected
BAD - command unknown or arguments invalid Result: OK - login completed, now in authenticated state
NO - login failure: user name or password rejected
BAD - command unknown or arguments invalid
The LOGIN command identifies the client to the server and carries the The LOGIN command identifies the client to the server and carries the
plaintext password authenticating this user. The LOGIN command plaintext password authenticating this user. The LOGIN command
SHOULD NOT be used except as a last resort (after attempting and SHOULD NOT be used except as a last resort (after attempting and
failing to authenticate using the AUTHENTICATE command one or more failing to authenticate using the AUTHENTICATE command one or more
times), and it is recommended that client implementations have a times), and it is recommended that client implementations have a
means to disable any automatic use of the LOGIN command. means to disable any automatic use of the LOGIN command.
A server MAY include a CAPABILITY response code in the tagged OK A server MAY include a CAPABILITY response code in the tagged OK
response to a successful LOGIN command in order to send capabilities response to a successful LOGIN command in order to send capabilities
automatically. It is unnecessary for a client to send a separate automatically. It is unnecessary for a client to send a separate
CAPABILITY command if it recognizes these automatic capabilities. CAPABILITY command if it recognizes these automatic capabilities.
Example: C: a001 LOGIN SMITH SESAME Example:
S: a001 OK LOGIN completed
C: a001 LOGIN SMITH SESAME
S: a001 OK LOGIN completed
Note: Use of the LOGIN command over an insecure network (such as the Note: Use of the LOGIN command over an insecure network (such as the
Internet) is a security risk, because anyone monitoring network Internet) is a security risk, because anyone monitoring network
traffic can obtain plaintext passwords. For that reason clients MUST traffic can obtain plaintext passwords. For that reason, clients
NOT use LOGIN on unsecure networks. MUST NOT use LOGIN on unsecure networks.
Unless either the client is accessing IMAP service on Implicit TLS Unless the client is accessing IMAP service on an Implicit TLS port
port [RFC8314], the STARTTLS command has been negotiated or some [RFC8314], the STARTTLS command has been negotiated, or some other
other mechanism that protects the session from password snooping has mechanism that protects the session from password snooping has been
been provided, a server implementation MUST implement a configuration provided, a server implementation MUST implement a configuration in
in which it advertises the LOGINDISABLED capability and does NOT which it advertises the LOGINDISABLED capability and does NOT permit
permit the LOGIN command. Server sites SHOULD NOT use any the LOGIN command. Server sites SHOULD NOT use any configuration
configuration which permits the LOGIN command without such a that permits the LOGIN command without such a protection mechanism
protection mechanism against password snooping. A client against password snooping. A client implementation MUST NOT send a
implementation MUST NOT send a LOGIN command if the LOGINDISABLED LOGIN command if the LOGINDISABLED capability is advertised.
capability is advertised.
6.3. Client Commands - Authenticated State 6.3. Client Commands - Authenticated State
In the authenticated state, commands that manipulate mailboxes as In the authenticated state, commands that manipulate mailboxes as
atomic entities are permitted. Of these commands, the SELECT and atomic entities are permitted. Of these commands, SELECT and EXAMINE
EXAMINE commands will select a mailbox for access and enter the will select a mailbox for access and enter the selected state.
selected state.
In addition to the universal commands (CAPABILITY, NOOP, and LOGOUT), In addition to the universal commands (CAPABILITY, NOOP, and LOGOUT),
the following commands are valid in the authenticated state: ENABLE, the following commands are valid in the authenticated state: ENABLE,
SELECT, EXAMINE, NAMESPACE, CREATE, DELETE, RENAME, SUBSCRIBE, SELECT, EXAMINE, NAMESPACE, CREATE, DELETE, RENAME, SUBSCRIBE,
UNSUBSCRIBE, LIST, STATUS, APPEND and IDLE. UNSUBSCRIBE, LIST, STATUS, APPEND, and IDLE.
6.3.1. ENABLE Command 6.3.1. ENABLE Command
Arguments: capability names Arguments: capability names
Responses: no specific responses for this command Responses: no specific responses for this command
Result: OK - Relevant capabilities enabled Result: OK - Relevant capabilities enabled
BAD - No arguments, or syntax error in an argument BAD - No arguments, or syntax error in an argument
Several IMAP extensions allow the server to return unsolicited Several IMAP extensions allow the server to return unsolicited
responses specific to these extensions in certain circumstances. responses specific to these extensions in certain circumstances.
However, servers cannot send those unsolicited responses (with the However, servers cannot send those unsolicited responses (with the
exception of response codes (see Section 7.1) included in tagged or exception of response codes (see Section 7.1) included in tagged or
untagged OK/NO/BAD responses, which can always be sent) until they untagged OK/NO/BAD responses, which can always be sent) until they
know that the clients support such extensions and thus won't choke on know that the clients support such extensions and thus will be able
the extension response data. to correctly parse and process the extension response data.
The ENABLE command provides an explicit indication from the client The ENABLE command provides an explicit indication from the client
that it supports particular extensions. It is designed such that the that it supports particular extensions. It is designed such that the
client can send a simple constant string with the extensions it client can send a simple constant string with the extensions it
supports, and the server will enable the shared subset that both supports, and the server will enable the shared subset that both
support. support.
The ENABLE command takes a list of capability names, and requests the The ENABLE command takes a list of capability names and requests the
server to enable the named extensions. Once enabled using ENABLE, server to enable the named extensions. Once enabled using ENABLE,
each extension remains active until the IMAP connection is closed. each extension remains active until the IMAP connection is closed.
For each argument, the server does the following: For each argument, the server does the following:
o If the argument is not an extension known to the server, the * If the argument is not an extension known to the server, the
server MUST ignore the argument. server MUST ignore the argument.
o If the argument is an extension known to the server, and it is not * If the argument is an extension known to the server, and it is not
specifically permitted to be enabled using ENABLE, the server MUST specifically permitted to be enabled using ENABLE, the server MUST
ignore the argument. (Note that knowing about an extension ignore the argument. (Note that knowing about an extension
doesn't necessarily imply supporting that extension.) doesn't necessarily imply supporting that extension.)
o If the argument is an extension that is supported by the server * If the argument is an extension that is supported by the server
and that needs to be enabled, the server MUST enable the extension and that needs to be enabled, the server MUST enable the extension
for the duration of the connection. Note that once an extension for the duration of the connection. Note that once an extension
is enabled, there is no way to disable it. is enabled, there is no way to disable it.
If the ENABLE command is successful, the server MUST send an untagged If the ENABLE command is successful, the server MUST send an untagged
ENABLED response Section 7.2.1, which includes all enabled extensions ENABLED response (Section 7.2.1), which includes all enabled
as specified above. The ENABLED response is sent even if no extensions as specified above. The ENABLED response is sent even if
extensions were enabled. no extensions were enabled.
Clients SHOULD only include extensions that need to be enabled by the Clients SHOULD only include extensions that need to be enabled by the
server. For example, a client can enable IMAP4rev2 specific server. For example, a client can enable IMAP4rev2-specific behavior
behaviour when both IMAP4rev1 and IMAP4rev2 are advertised in the when both IMAP4rev1 and IMAP4rev2 are advertised in the CAPABILITY
CAPABILITY response. Future RFCs may add to this list. response. Future RFCs may add to this list.
The ENABLE command is only valid in the authenticated state, before The ENABLE command is only valid in the authenticated state, before
any mailbox is selected. Clients MUST NOT issue ENABLE once they any mailbox is selected. Clients MUST NOT issue ENABLE once they
SELECT/EXAMINE a mailbox; however, server implementations don't have SELECT/EXAMINE a mailbox; however, server implementations don't have
to check that no mailbox is selected or was previously selected to check that no mailbox is selected or was previously selected
during the duration of a connection. during the duration of a connection.
The ENABLE command can be issued multiple times in a session. It is The ENABLE command can be issued multiple times in a session. It is
additive; i.e., "ENABLE a b", followed by "ENABLE c" is the same as a additive; that is, "ENABLE a b", followed by "ENABLE c", is the same
single command "ENABLE a b c". When multiple ENABLE commands are as a single command "ENABLE a b c". When multiple ENABLE commands
issued, each corresponding ENABLED response SHOULD only contain are issued, each corresponding ENABLED response SHOULD only contain
extensions enabled by the corresponding ENABLE command, i.e. for the extensions enabled by the corresponding ENABLE command, i.e., for the
above example, the ENABLED response to "ENABLE c" should not contain above example, the ENABLED response to "ENABLE c" should not contain
"a" or "b". "a" or "b".
There are no limitations on pipelining ENABLE. For example, it is There are no limitations on pipelining ENABLE. For example, it is
possible to send ENABLE and then immediately SELECT, or a LOGIN possible to send ENABLE and then immediately SELECT, or a LOGIN
immediately followed by ENABLE. immediately followed by ENABLE.
The server MUST NOT change the CAPABILITY list as a result of The server MUST NOT change the CAPABILITY list as a result of
executing ENABLE; i.e., a CAPABILITY command issued right after an executing ENABLE; that is, a CAPABILITY command issued right after an
ENABLE command MUST list the same capabilities as a CAPABILITY ENABLE command MUST list the same capabilities as a CAPABILITY
command issued before the ENABLE command. This is demonstrated in command issued before the ENABLE command. This is demonstrated in
the following example. Note that below "X-GOOD-IDEA" is a fictitious the following example. Note that below "X-GOOD-IDEA" is a fictitious
extension capability that can be ENABLEd. extension capability that can be ENABLED.
C: t1 CAPABILITY C: t1 CAPABILITY
S: * CAPABILITY IMAP4rev2 ID LITERAL+ X-GOOD-IDEA S: * CAPABILITY IMAP4rev2 ID LITERAL+ X-GOOD-IDEA
S: t1 OK foo S: t1 OK foo
C: t2 ENABLE CONDSTORE X-GOOD-IDEA C: t2 ENABLE CONDSTORE X-GOOD-IDEA
S: * ENABLED X-GOOD-IDEA S: * ENABLED X-GOOD-IDEA
S: t2 OK foo S: t2 OK foo
C: t3 CAPABILITY C: t3 CAPABILITY
S: * CAPABILITY IMAP4rev2 ID LITERAL+ X-GOOD-IDEA S: * CAPABILITY IMAP4rev2 ID LITERAL+ X-GOOD-IDEA
S: t3 OK foo again S: t3 OK foo again
In the following example, the client enables CONDSTORE extension In the following example, the client enables the Conditional Store
[RFC7162]: (CONDSTORE) extension [RFC7162]:
C: a1 ENABLE CONDSTORE C: a1 ENABLE CONDSTORE
S: * ENABLED CONDSTORE S: * ENABLED CONDSTORE
S: a1 OK Conditional Store enabled S: a1 OK Conditional Store enabled
6.3.1.1. Note to Designers of Extensions That May Use the ENABLE 6.3.1.1. Note to Designers of Extensions That May Use the ENABLE
Command Command
Designers of IMAP extensions are discouraged from creating extensions Designers of IMAP extensions are discouraged from creating extensions
that require ENABLE unless there is no good alternative design. that require ENABLE unless there is no good alternative design.
Specifically, extensions that cause potentially incompatible behavior Specifically, extensions that cause potentially incompatible behavior
changes to deployed server responses (and thus benefit from ENABLE) changes to deployed server responses (and thus benefit from ENABLE)
have a higher complexity cost than extensions that do not. have a higher complexity cost than extensions that do not.
6.3.2. SELECT Command 6.3.2. SELECT Command
Arguments: mailbox name Arguments: mailbox name
Responses: REQUIRED untagged responses: FLAGS, EXISTS, LIST Responses: REQUIRED untagged responses: FLAGS, EXISTS, LIST
REQUIRED OK untagged responses: PERMANENTFLAGS, REQUIRED OK untagged responses: PERMANENTFLAGS,
UIDNEXT, UIDVALIDITY UIDNEXT, UIDVALIDITY
Result: OK - select completed, now in selected state Result: OK - select completed, now in selected state
NO - select failure, now in authenticated state: no NO - select failure, now in authenticated state: no
such mailbox, can't access mailbox such mailbox, can't access mailbox
BAD - command unknown or arguments invalid BAD - command unknown or arguments invalid
The SELECT command selects a mailbox so that messages in the mailbox The SELECT command selects a mailbox so that messages in the mailbox
can be accessed. Before returning an OK to the client, the server can be accessed. Before returning an OK to the client, the server
MUST send the following untagged data to the client. (The order of MUST send the following untagged data to the client. (The order of
individual responses is not important.) Note that earlier versions individual responses is not important.) Note that earlier versions
of this protocol (e.g. IMAP4rev1 version specified in RFC 2060) only of this protocol, such as the IMAP4rev1 version specified in
required the FLAGS and EXISTS untagged responses and UIDVALIDITY [RFC2060], only required the FLAGS and EXISTS untagged responses and
response code; consequently, client implementations SHOULD implement UIDVALIDITY response code. Client implementations that need to
default behavior for missing data as discussed with the individual remain compatible with such older IMAP versions have to implement
item. default behavior for missing data, as discussed with the individual
items.
FLAGS Defined flags in the mailbox. See the description of the FLAGS
FLAGS response in Section 7.3.5 for more detail. Defined flags in the mailbox. See the description of the FLAGS
response in Section 7.3.5 for more detail.
<n> EXISTS The number of messages in the mailbox. See the <n> EXISTS
description of the EXISTS response in Section 7.4.1 for more The number of messages in the mailbox. See the description of the
detail. EXISTS response in Section 7.4.1 for more detail.
LIST The server MUST return a LIST response with the mailbox name. LIST
The list of mailbox attributes MUST be accurate. If the server The server MUST return a LIST response with the mailbox name. The
allows de-normalized UTF-8 mailbox names (see Section 5.1) and the list of mailbox attributes MUST be accurate. If the server allows
denormalized UTF-8 mailbox names (see Section 5.1) and the
supplied mailbox name differs from the normalized version, the supplied mailbox name differs from the normalized version, the
server MUST return LIST with the OLDNAME extended data item. See server MUST return LIST with the OLDNAME extended data item. See
Section 6.3.9.7 for more details. Section 6.3.9.7 for more details.
OK [PERMANENTFLAGS (<list of flags>)] A list of message flags that OK [PERMANENTFLAGS (<list of flags>)]
the client can change permanently. If this is missing, the client A list of message flags that the client can change permanently.
should assume that all flags can be changed permanently. If this is missing, the client should assume that all flags can be
changed permanently.
OK [UIDNEXT <n>] The next unique identifier value. Refer to OK [UIDNEXT <n>]
Section 2.3.1.1 for more information. The next unique identifier value. Refer to Section 2.3.1.1 for
more information.
OK [UIDVALIDITY <n>] The unique identifier validity value. Refer to OK [UIDVALIDITY <n>]
Section 2.3.1.1 for more information. The unique identifier validity value. Refer to Section 2.3.1.1
for more information.
Only one mailbox can be selected at a time in a connection; Only one mailbox can be selected at a time in a connection;
simultaneous access to multiple mailboxes requires multiple simultaneous access to multiple mailboxes requires multiple
connections. The SELECT command automatically deselects any connections. The SELECT command automatically deselects any
currently selected mailbox before attempting the new selection. currently selected mailbox before attempting the new selection.
Consequently, if a mailbox is selected and a SELECT command that Consequently, if a mailbox is selected and a SELECT command that
fails is attempted, no mailbox is selected. When deselecting a fails is attempted, no mailbox is selected. When deselecting a
selected mailbox, the server MUST return an untagged OK response with selected mailbox, the server MUST return an untagged OK response with
the "[CLOSED]" response code when the currently selected mailbox is the "[CLOSED]" response code when the currently selected mailbox is
closed (see Paragraph 10). closed (see Section 7.1).
If the client is permitted to modify the mailbox, the server SHOULD If the client is permitted to modify the mailbox, the server SHOULD
prefix the text of the tagged OK response with the "[READ-WRITE]" prefix the text of the tagged OK response with the "[READ-WRITE]"
response code. response code.
If the client is not permitted to modify the mailbox but is permitted If the client is not permitted to modify the mailbox but is permitted
read access, the mailbox is selected as read-only, and the server read access, the mailbox is selected as read-only, and the server
MUST prefix the text of the tagged OK response to SELECT with the MUST prefix the text of the tagged OK response to SELECT with the
"[READ-ONLY]" response code. Read-only access through SELECT differs "[READ-ONLY]" response code. Read-only access through SELECT differs
from the EXAMINE command in that certain read-only mailboxes MAY from the EXAMINE command in that certain read-only mailboxes MAY
permit the change of permanent state on a per-user (as opposed to permit the change of permanent state on a per-user (as opposed to
global) basis. Netnews messages marked in a server-based .newsrc global) basis. Netnews messages marked in a server-based .newsrc
file are an example of such per-user permanent state that can be file are an example of such per-user permanent state that can be
modified with read-only mailboxes. modified with read-only mailboxes.
Example: C: A142 SELECT INBOX Example:
S: * 172 EXISTS
S: * OK [UIDVALIDITY 3857529045] UIDs valid
S: * OK [UIDNEXT 4392] Predicted next UID
S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
S: * OK [PERMANENTFLAGS (\Deleted \Seen \*)] Limited
S: * LIST () "/" INBOX
S: A142 OK [READ-WRITE] SELECT completed
Example: C: A142 SELECT INBOX C: A142 SELECT INBOX
S: * 172 EXISTS S: * 172 EXISTS
S: * OK [UIDVALIDITY 3857529045] UIDs valid S: * OK [UIDVALIDITY 3857529045] UIDs valid
S: * OK [UIDNEXT 4392] Predicted next UID S: * OK [UIDNEXT 4392] Predicted next UID
S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft) S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
S: * OK [PERMANENTFLAGS (\Deleted \Seen \*)] Limited S: * OK [PERMANENTFLAGS (\Deleted \Seen \*)] Limited
S: A142 OK [READ-WRITE] SELECT completed S: * LIST () "/" INBOX
[...some time later...] S: A142 OK [READ-WRITE] SELECT completed
C: A143 SELECT Drafts
S: * OK [CLOSED] Previous mailbox is now closed
S: * 5 EXISTS
S: * OK [UIDVALIDITY 9877410381] UIDs valid
S: * OK [UIDNEXT 102] Predicted next UID
S: * LIST () "/" Drafts
S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
S: * OK [PERMANENTFLAGS (\Deleted \Seen \Answered
\Flagged \Draft \*)] System flags and keywords allowed
S: A143 OK [READ-WRITE] SELECT completed
Note that IMAP4rev1 compliant servers can also send the untagged Example:
RECENT response which was deprecated in IMAP4rev2. E.g. "* 0
RECENT". Pure IMAP4rev2 clients are advised to ignore the untagged C: A142 SELECT INBOX
RECENT response. S: * 172 EXISTS
S: * OK [UIDVALIDITY 3857529045] UIDs valid
S: * OK [UIDNEXT 4392] Predicted next UID
S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
S: * OK [PERMANENTFLAGS (\Deleted \Seen \*)] Limited
S: A142 OK [READ-WRITE] SELECT completed
[...some time later...]
C: A143 SELECT Drafts
S: * OK [CLOSED] Previous mailbox is now closed
S: * 5 EXISTS
S: * OK [UIDVALIDITY 9877410381] UIDs valid
S: * OK [UIDNEXT 102] Predicted next UID
S: * LIST () "/" Drafts
S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
S: * OK [PERMANENTFLAGS (\Deleted \Seen \Answered
\Flagged \Draft \*)] System flags and keywords allowed
S: A143 OK [READ-WRITE] SELECT completed
Note that IMAP4rev1-compliant servers can also send the untagged
RECENT response that was deprecated in IMAP4rev2, e.g., "* 0 RECENT".
Pure IMAP4rev2 clients are advised to ignore the untagged RECENT
response.
6.3.3. EXAMINE Command 6.3.3. EXAMINE Command
Arguments: mailbox name Arguments: mailbox name
Responses: REQUIRED untagged responses: FLAGS, EXISTS, LIST Responses: REQUIRED untagged responses: FLAGS, EXISTS, LIST
REQUIRED OK untagged responses: PERMANENTFLAGS, REQUIRED OK untagged responses: PERMANENTFLAGS,
UIDNEXT, UIDVALIDITY UIDNEXT, UIDVALIDITY
Result: OK - examine completed, now in selected state Result: OK - examine completed, now in selected state
NO - examine failure, now in authenticated state: no NO - examine failure, now in authenticated state: no
such mailbox, can't access mailbox BAD - command unknown such mailbox, can't access mailbox
or arguments invalid BAD - command unknown or arguments invalid
The EXAMINE command is identical to SELECT and returns the same The EXAMINE command is identical to SELECT and returns the same
output; however, the selected mailbox is identified as read-only. No output; however, the selected mailbox is identified as read-only. No
changes to the permanent state of the mailbox, including per-user changes to the permanent state of the mailbox, including per-user
state, are permitted. state, are permitted.
The text of the tagged OK response to the EXAMINE command MUST begin The text of the tagged OK response to the EXAMINE command MUST begin
with the "[READ-ONLY]" response code. with the "[READ-ONLY]" response code.
Example: C: A932 EXAMINE blurdybloop Example:
S: * 17 EXISTS
S: * OK [UIDVALIDITY 3857529045] UIDs valid C: A932 EXAMINE blurdybloop
S: * OK [UIDNEXT 4392] Predicted next UID S: * 17 EXISTS
S: * LIST () "/" blurdybloop S: * OK [UIDVALIDITY 3857529045] UIDs valid
S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft) S: * OK [UIDNEXT 4392] Predicted next UID
S: * OK [PERMANENTFLAGS ()] No permanent flags permitted S: * LIST () "/" blurdybloop
S: A932 OK [READ-ONLY] EXAMINE completed S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
S: * OK [PERMANENTFLAGS ()] No permanent flags permitted
S: A932 OK [READ-ONLY] EXAMINE completed
6.3.4. CREATE Command 6.3.4. CREATE Command
Arguments: mailbox name Arguments: mailbox name
Responses: OPTIONAL untagged response: LIST Responses: OPTIONAL untagged response: LIST
Result: OK - create completed Result: OK - create completed
NO - create failure: can't create mailbox with that name NO - create failure: can't create mailbox with that
BAD - command unknown or arguments invalid name
BAD - command unknown or arguments invalid
The CREATE command creates a mailbox with the given name. An OK The CREATE command creates a mailbox with the given name. An OK
response is returned only if a new mailbox with that name has been response is returned only if a new mailbox with that name has been
created. It is an error to attempt to create INBOX or a mailbox with created. It is an error to attempt to create INBOX or a mailbox with
a name that refers to an extant mailbox. Any error in creation will a name that refers to an extant mailbox. Any error in creation will
return a tagged NO response. If a client attempts to create a UTF-8 return a tagged NO response. If a client attempts to create a UTF-8
mailbox name that is not a valid Net-Unicode name, the server MUST mailbox name that is not a valid Net-Unicode name, the server MUST
reject the creation or convert the name to Net-Unicode prior to reject the creation or convert the name to Net-Unicode prior to
creating the mailbox. If the server decides to convert (normalize) creating the mailbox. If the server decides to convert (normalize)
the name, it SHOULD return an untagged LIST with OLDNAME extended the name, it SHOULD return an untagged LIST with an OLDNAME extended
data item, with the OLDNAME value being the supplied mailbox name and data item, with the OLDNAME value being the supplied mailbox name and
the name parameter being the normalized mailbox name. (See the name parameter being the normalized mailbox name. (See
Section 6.3.9.7 for more details.) Section 6.3.9.7 for more details.)
Mailboxes created in one IMAP session MAY be announced to other IMAP Mailboxes created in one IMAP session MAY be announced to other IMAP
sessions using unsolicited LIST response. If the server sessions using an unsolicited LIST response. If the server
automatically subscribes a mailbox when it is created, then the automatically subscribes a mailbox when it is created, then the
unsolicited LIST response for each affected subscribed mailbox name unsolicited LIST response for each affected subscribed mailbox name
MUST include the \Subscribed attribute. MUST include the \Subscribed attribute.
If the mailbox name is suffixed with the server's hierarchy separator If the mailbox name is suffixed with the server's hierarchy separator
character (as returned from the server by a LIST command), this is a character (as returned from the server by a LIST command), this is a
declaration that the client intends to create mailbox names under declaration that the client intends to create mailbox names under
this name in the hierarchy. Server implementations that do not this name in the hierarchy. Server implementations that do not
require this declaration MUST ignore the declaration. In any case, require this declaration MUST ignore the declaration. In any case,
the name created is without the trailing hierarchy delimiter. the name created is without the trailing hierarchy delimiter.
skipping to change at page 42, line 4 skipping to change at line 1936
If the mailbox name is suffixed with the server's hierarchy separator If the mailbox name is suffixed with the server's hierarchy separator
character (as returned from the server by a LIST command), this is a character (as returned from the server by a LIST command), this is a
declaration that the client intends to create mailbox names under declaration that the client intends to create mailbox names under
this name in the hierarchy. Server implementations that do not this name in the hierarchy. Server implementations that do not
require this declaration MUST ignore the declaration. In any case, require this declaration MUST ignore the declaration. In any case,
the name created is without the trailing hierarchy delimiter. the name created is without the trailing hierarchy delimiter.
If the server's hierarchy separator character appears elsewhere in If the server's hierarchy separator character appears elsewhere in
the name, the server SHOULD create any superior hierarchical names the name, the server SHOULD create any superior hierarchical names
that are needed for the CREATE command to be successfully completed. that are needed for the CREATE command to be successfully completed.
In other words, an attempt to create "foo/bar/zap" on a server in In other words, an attempt to create "foo/bar/zap" on a server in
which "/" is the hierarchy separator character SHOULD create foo/ and which "/" is the hierarchy separator character SHOULD create foo/ and
foo/bar/ if they do not already exist. foo/bar/ if they do not already exist.
If a new mailbox is created with the same name as a mailbox which was If a new mailbox is created with the same name as a mailbox that was
deleted, its unique identifiers MUST be greater than any unique deleted, its unique identifiers MUST be greater than any unique
identifiers used in the previous incarnation of the mailbox unless identifiers used in the previous incarnation of the mailbox unless
the new incarnation has a different unique identifier validity value. the new incarnation has a different unique identifier validity value.
See the description of the UID command in Section 6.4.9 for more See the description of the UID command in Section 6.4.9 for more
detail. detail.
Example: C: A003 CREATE owatagusiam/ Example:
S: A003 OK CREATE completed
C: A004 CREATE owatagusiam/blurdybloop
S: A004 OK CREATE completed
C: A005 CREATE NonNormalized
S: * LIST () "/" "Normalized" ("OLDNAME" ("NonNormalized"))
S: A005 OK CREATE completed
(in the last example imagine that "NonNormalized" is C: A003 CREATE owatagusiam/
a non NFC normalized Unicode mailbox name and that S: A003 OK CREATE completed
"Normalized" is its NFC normalized version.) C: A004 CREATE owatagusiam/blurdybloop
S: A004 OK CREATE completed
C: A005 CREATE NonNormalized
S: * LIST () "/" "Normalized" ("OLDNAME" ("NonNormalized"))
S: A005 OK CREATE completed
Note: The interpretation of this example depends on whether "/" (In the last example, imagine that "NonNormalized" is a non-NFC
was returned as the hierarchy separator from LIST. If "/" is the normalized Unicode mailbox name and that "Normalized" is its NFC
hierarchy separator, a new level of hierarchy named "owatagusiam" normalized version.)
with a member called "blurdybloop" is created. Otherwise, two
mailboxes at the same hierarchy level are created. | Note: The interpretation of this example depends on whether "/"
| was returned as the hierarchy separator from LIST. If "/" is
| the hierarchy separator, a new level of hierarchy named
| "owatagusiam" with a member called "blurdybloop" is created.
| Otherwise, two mailboxes at the same hierarchy level are
| created.
6.3.5. DELETE Command 6.3.5. DELETE Command
Arguments: mailbox name Arguments: mailbox name
Responses: OPTIONAL untagged response: LIST Responses: OPTIONAL untagged response: LIST
Result: OK - delete completed Result: OK - delete completed
NO - delete failure: can't delete mailbox with that name NO - delete failure: can't delete mailbox with that
BAD - command unknown or arguments invalid name
BAD - command unknown or arguments invalid
The DELETE command permanently removes the mailbox with the given The DELETE command permanently removes the mailbox with the given
name. A tagged OK response is returned only if the mailbox has been name. A tagged OK response is returned only if the mailbox has been
deleted. It is an error to attempt to delete INBOX or a mailbox name deleted. It is an error to attempt to delete INBOX or a mailbox name
that does not exist. that does not exist.
The DELETE command MUST NOT remove inferior hierarchical names. For The DELETE command MUST NOT remove inferior hierarchical names. For
example, if a mailbox "foo" has an inferior "foo.bar" (assuming "." example, if a mailbox "foo" has an inferior "foo.bar" (assuming "."
is the hierarchy delimiter character), removing "foo" MUST NOT remove is the hierarchy delimiter character), removing "foo" MUST NOT remove
"foo.bar". It is an error to attempt to delete a name that has "foo.bar". It is an error to attempt to delete a name that has
inferior hierarchical names and also has the \Noselect mailbox name inferior hierarchical names and also has the \Noselect mailbox name
attribute (see the description of the LIST response (Section 7.3.1) attribute (see the description of the LIST response (Section 7.3.1)
for more details). for more details).
It is permitted to delete a name that has inferior hierarchical names It is permitted to delete a name that has inferior hierarchical names
and does not have the \Noselect mailbox name attribute. If the and does not have the \Noselect mailbox name attribute. If the
server implementation does not permit deleting the name while server implementation does not permit deleting the name while
inferior hierarchical names exists then it SHOULD disallow the DELETE inferior hierarchical names exist, then it SHOULD disallow the DELETE
command by returning a tagged NO response. The NO response SHOULD command by returning a tagged NO response. The NO response SHOULD
include the HASCHILDREN response code. Alternatively the server MAY include the HASCHILDREN response code. Alternatively, the server MAY
allow the DELETE command, but sets the \Noselect mailbox name allow the DELETE command, but it sets the \Noselect mailbox name
attribute for that name. attribute for that name.
If the server returns OK response, all messages in that mailbox are If the server returns an OK response, all messages in that mailbox
removed by the DELETE command. are removed by the DELETE command.
The value of the highest-used unique identifier of the deleted The value of the highest-used unique identifier of the deleted
mailbox MUST be preserved so that a new mailbox created with the same mailbox MUST be preserved so that a new mailbox created with the same
name will not reuse the identifiers of the former incarnation, unless name will not reuse the identifiers of the former incarnation, unless
the new incarnation has a different unique identifier validity value. the new incarnation has a different unique identifier validity value.
See the description of the UID command in Section 6.4.9 for more See the description of the UID command in Section 6.4.9 for more
detail. detail.
If the server decides to convert (normalize) the mailbox name, it If the server decides to convert (normalize) the mailbox name, it
SHOULD return an untagged LIST with the "\NonExistent" attribute and SHOULD return an untagged LIST with the "\NonExistent" attribute and
OLDNAME extended data item, with the OLDNAME value being the supplied OLDNAME extended data item, with the OLDNAME value being the supplied
mailbox name and the name parameter being the normalized mailbox mailbox name and the name parameter being the normalized mailbox
name. (See Section 6.3.9.7 for more details.) name. (See Section 6.3.9.7 for more details.)
Mailboxes deleted in one IMAP session MAY be announced to other IMAP Mailboxes deleted in one IMAP session MAY be announced to other IMAP
sessions using unsolicited LIST response, containing the sessions using an unsolicited LIST response, containing the
"\NonExistent" attribute. "\NonExistent" attribute.
Example: C: A682 LIST "" * Example:
S: * LIST () "/" blurdybloop
S: * LIST (\Noselect) "/" foo
S: * LIST () "/" foo/bar
S: A682 OK LIST completed
C: A683 DELETE blurdybloop
S: A683 OK DELETE completed
C: A684 DELETE foo
S: A684 NO Name "foo" has inferior hierarchical names
C: A685 DELETE foo/bar
S: A685 OK DELETE Completed
C: A686 LIST "" *
S: * LIST (\Noselect) "/" foo
S: A686 OK LIST completed
C: A687 DELETE foo
S: A687 OK DELETE Completed
Example: C: A82 LIST "" * C: A682 LIST "" *
S: * LIST () "." blurdybloop S: * LIST () "/" blurdybloop
S: * LIST () "." foo S: * LIST (\Noselect) "/" foo
S: * LIST () "." foo.bar S: * LIST () "/" foo/bar
S: A82 OK LIST completed S: A682 OK LIST completed
C: A83 DELETE blurdybloop C: A683 DELETE blurdybloop
S: A83 OK DELETE completed S: A683 OK DELETE completed
C: A84 DELETE foo C: A684 DELETE foo
S: A84 OK DELETE Completed S: A684 NO Name "foo" has inferior hierarchical names
C: A85 LIST "" * C: A685 DELETE foo/bar
S: * LIST () "." foo.bar S: A685 OK DELETE Completed
S: A85 OK LIST completed C: A686 LIST "" *
C: A86 LIST "" % S: * LIST (\Noselect) "/" foo
S: * LIST (\Noselect) "." foo S: A686 OK LIST completed
S: A86 OK LIST completed C: A687 DELETE foo
S: A687 OK DELETE Completed
Example:
C: A82 LIST "" *
S: * LIST () "." blurdybloop
S: * LIST () "." foo
S: * LIST () "." foo.bar
S: A82 OK LIST completed
C: A83 DELETE blurdybloop
S: A83 OK DELETE completed
C: A84 DELETE foo
S: A84 OK DELETE Completed
C: A85 LIST "" *
S: * LIST () "." foo.bar
S: A85 OK LIST completed
C: A86 LIST "" %
S: * LIST (\Noselect) "." foo
S: A86 OK LIST completed
6.3.6. RENAME Command 6.3.6. RENAME Command
Arguments: existing mailbox name Arguments: existing mailbox name
new mailbox name
Responses: OPTIONAL untagged response: LIST new mailbox name
Result: OK - rename completed Responses: OPTIONAL untagged response: LIST
NO - rename failure: can't rename mailbox with that name,
can't rename to mailbox with that name Result: OK - rename completed
BAD - command unknown or arguments invalid NO - rename failure: can't rename mailbox with that
name, can't rename to mailbox with that name
BAD - command unknown or arguments invalid
The RENAME command changes the name of a mailbox. A tagged OK The RENAME command changes the name of a mailbox. A tagged OK
response is returned only if the mailbox has been renamed. It is an response is returned only if the mailbox has been renamed. It is an
error to attempt to rename from a mailbox name that does not exist or error to attempt to rename from a mailbox name that does not exist or
to a mailbox name that already exists. Any error in renaming will to a mailbox name that already exists. Any error in renaming will
return a tagged NO response. return a tagged NO response.
If the name has inferior hierarchical names, then the inferior If the name has inferior hierarchical names, then the inferior
hierarchical names MUST also be renamed. For example, a rename of hierarchical names MUST also be renamed. For example, a rename of
"foo" to "zap" will rename "foo/bar" (assuming "/" is the hierarchy "foo" to "zap" will rename "foo/bar" (assuming "/" is the hierarchy
delimiter character) to "zap/bar". delimiter character) to "zap/bar".
If the server's hierarchy separator character appears in the new If the server's hierarchy separator character appears in the new
mailbox name, the server SHOULD create any superior hierarchical mailbox name, the server SHOULD create any superior hierarchical
names that are needed for the RENAME command to complete names that are needed for the RENAME command to complete
successfully. In other words, an attempt to rename "foo/bar/zap" to successfully. In other words, an attempt to rename "foo/bar/zap" to
baz/rag/zowie on a server in which "/" is the hierarchy separator "baz/rag/zowie" on a server in which "/" is the hierarchy separator
character in the corresponding namespace SHOULD create baz/ and baz/ character in the corresponding namespace SHOULD create "baz/" and
rag/ if they do not already exist. "baz/rag/" if they do not already exist.
The value of the highest-used unique identifier of the old mailbox The value of the highest-used unique identifier of the old mailbox
name MUST be preserved so that a new mailbox created with the same name MUST be preserved so that a new mailbox created with the same
name will not reuse the identifiers of the former incarnation, unless name will not reuse the identifiers of the former incarnation, unless
the new incarnation has a different unique identifier validity value. the new incarnation has a different unique identifier validity value.
See the description of the UID command in Section 6.4.9 for more See the description of the UID command in Section 6.4.9 for more
detail. detail.
Renaming INBOX is permitted (i.e. it doesn't result in a tagged BAD Renaming INBOX is permitted and does not result in a tagged BAD
response), and has special behavior. (Note that some servers response, and it has special behavior: It moves all messages in INBOX
to a new mailbox with the given name, leaving INBOX empty. If the
server implementation supports inferior hierarchical names of INBOX,
these are unaffected by a rename of INBOX. (Note that some servers
disallow renaming INBOX by returning a tagged NO response, so clients disallow renaming INBOX by returning a tagged NO response, so clients
need to be able to handle such RENAME failing). It moves all need to be able to handle the failure of such RENAME commands.)
messages in INBOX to a new mailbox with the given name, leaving INBOX
empty. If the server implementation supports inferior hierarchical
names of INBOX, these are unaffected by a rename of INBOX.
If the server allows creation of mailboxes with names that are not If the server allows creation of mailboxes with names that are not
valid Net-Unicode names, the server normalizes both the existing valid Net-Unicode names, the server normalizes both the existing
mailbox name parameter and the new mailbox name parameter. If the mailbox name parameter and the new mailbox name parameter. If the
normalized version of any of these 2 parameters differs from the normalized version of any of these 2 parameters differs from the
corresponding supplied version, the server SHOULD return an untagged corresponding supplied version, the server SHOULD return an untagged
LIST response with OLDNAME extended data item, with the OLDNAME value LIST response with an OLDNAME extended data item, with the OLDNAME
being the supplied existing mailbox name and the name parameter being value being the supplied existing mailbox name and the name parameter
the normalized new mailbox name (see Section 6.3.9.7). This would being the normalized new mailbox name (see Section 6.3.9.7). This
allow the client to correlate the supplied name with the normalized would allow the client to correlate the supplied name with the
name. normalized name.
Mailboxes renamed in one IMAP session MAY be announced to other IMAP Mailboxes renamed in one IMAP session MAY be announced to other IMAP
sessions using unsolicited LIST response with OLDNAME extended data sessions using an unsolicited LIST response with an OLDNAME extended
item. data item.
In both of the above cases: if the server automatically subscribes a In both of the above cases, if the server automatically subscribes a
mailbox when it is renamed, then the unsolicited LIST response for mailbox when it is renamed, then the unsolicited LIST response for
each affected subscribed mailbox name MUST include the \Subscribed each affected subscribed mailbox name MUST include the \Subscribed
attribute. No unsolicited LIST responses need to be sent for attribute. No unsolicited LIST responses need to be sent for child
children mailboxes, if any. When INBOX is successfully renamed, a mailboxes. When INBOX is successfully renamed, it is assumed that a
new INBOX is assumed to be created. No unsolicited LIST responses new INBOX is created. No unsolicited LIST responses need to be sent
need to be sent for INBOX in this case. for INBOX in this case.
Examples: C: A682 LIST "" * Examples:
S: * LIST () "/" blurdybloop
S: * LIST (\Noselect) "/" foo
S: * LIST () "/" foo/bar
S: A682 OK LIST completed
C: A683 RENAME blurdybloop sarasoop
S: A683 OK RENAME completed
C: A684 RENAME foo zowie
S: A684 OK RENAME Completed
C: A685 LIST "" *
S: * LIST () "/" sarasoop
S: * LIST (\Noselect) "/" zowie
S: * LIST () "/" zowie/bar
S: A685 OK LIST completed
C: Z432 LIST "" * C: A682 LIST "" *
S: * LIST () "." INBOX S: * LIST () "/" blurdybloop
S: * LIST () "." INBOX.bar S: * LIST (\Noselect) "/" foo
S: Z432 OK LIST completed S: * LIST () "/" foo/bar
C: Z433 RENAME INBOX old-mail S: A682 OK LIST completed
S: Z433 OK RENAME completed C: A683 RENAME blurdybloop sarasoop
C: Z434 LIST "" * S: A683 OK RENAME completed
S: * LIST () "." INBOX C: A684 RENAME foo zowie
S: * LIST () "." INBOX.bar S: A684 OK RENAME Completed
S: * LIST () "." old-mail C: A685 LIST "" *
S: Z434 OK LIST completed S: * LIST () "/" sarasoop
S: * LIST (\Noselect) "/" zowie
S: * LIST () "/" zowie/bar
S: A685 OK LIST completed
C: Z432 LIST "" *
S: * LIST () "." INBOX
S: * LIST () "." INBOX.bar
S: Z432 OK LIST completed
C: Z433 RENAME INBOX old-mail
S: Z433 OK RENAME completed
C: Z434 LIST "" *
S: * LIST () "." INBOX
S: * LIST () "." INBOX.bar
S: * LIST () "." old-mail
S: Z434 OK LIST completed
Note that renaming a mailbox doesn't update subscription information Note that renaming a mailbox doesn't update subscription information
on the original name. To keep subscription information in sync, the on the original name. To keep subscription information in sync, the
following sequence of commands can be used: following sequence of commands can be used:
C: 1001 RENAME X Y C: 1001 RENAME X Y
C: 1002 SUBSCRIBE Y C: 1002 SUBSCRIBE Y
C: 1003 UNSUBSCRIBE X C: 1003 UNSUBSCRIBE X
Note that the above sequence of commands doesn't account for updating Note that the above sequence of commands doesn't account for updating
subscription for any children mailboxes of mailbox X. the subscription for any child mailboxes of mailbox X.
6.3.7. SUBSCRIBE Command 6.3.7. SUBSCRIBE Command
Arguments: mailbox Arguments: mailbox
Responses: no specific responses for this command Responses: no specific responses for this command
Result: OK - subscribe completed Result: OK - subscribe completed
NO - subscribe failure: can't subscribe to that name NO - subscribe failure: can't subscribe to that name
BAD - command unknown or arguments invalid BAD - command unknown or arguments invalid
The SUBSCRIBE command adds the specified mailbox name to the server's The SUBSCRIBE command adds the specified mailbox name to the server's
set of "active" or "subscribed" mailboxes as returned by the LIST set of "active" or "subscribed" mailboxes as returned by the LIST
(SUBSCRIBED) command. This command returns a tagged OK response if (SUBSCRIBED) command. This command returns a tagged OK response if
the subscription is successful or if the mailbox is already the subscription is successful or if the mailbox is already
subscribed. subscribed.
A server MAY validate the mailbox argument to SUBSCRIBE to verify A server MAY validate the mailbox argument to SUBSCRIBE to verify
that it exists. However, it SHOULD NOT unilaterally remove an that it exists. However, it SHOULD NOT unilaterally remove an
existing mailbox name from the subscription list even if a mailbox by existing mailbox name from the subscription list even if a mailbox by
that name no longer exists. that name no longer exists.
Note: This requirement is because a server site can choose to | Note: This requirement is because a server site can choose to
routinely remove a mailbox with a well-known name (e.g., "system- | routinely remove a mailbox with a well-known name (e.g.,
alerts") after its contents expire, with the intention of | "system-alerts") after its contents expire, with the intention
recreating it when new contents are appropriate. | of recreating it when new contents are appropriate.
Example: C: A002 SUBSCRIBE #news.comp.mail.mime Example:
S: A002 OK SUBSCRIBE completed
C: A002 SUBSCRIBE #news.comp.mail.mime
S: A002 OK SUBSCRIBE completed
6.3.8. UNSUBSCRIBE Command 6.3.8. UNSUBSCRIBE Command
Arguments: mailbox name Arguments: mailbox name
Responses: no specific responses for this command Responses: no specific responses for this command
Result: OK - unsubscribe completed Result: OK - unsubscribe completed
NO - unsubscribe failure: can't unsubscribe that name NO - unsubscribe failure: can't unsubscribe that name
BAD - command unknown or arguments invalid BAD - command unknown or arguments invalid
The UNSUBSCRIBE command removes the specified mailbox name from the The UNSUBSCRIBE command removes the specified mailbox name from the
server's set of "active" or "subscribed" mailboxes as returned by the server's set of "active" or "subscribed" mailboxes as returned by the
LIST (SUBSCRIBED) command. This command returns a tagged OK response LIST (SUBSCRIBED) command. This command returns a tagged OK response
if the unsubscription is successful or if the mailbox is not if the unsubscription is successful or if the mailbox is not
subscribed. subscribed.
Example: C: A002 UNSUBSCRIBE #news.comp.mail.mime Example:
S: A002 OK UNSUBSCRIBE completed
C: A002 UNSUBSCRIBE #news.comp.mail.mime
S: A002 OK UNSUBSCRIBE completed
6.3.9. LIST Command 6.3.9. LIST Command
Arguments (basic): reference name Arguments (basic):
mailbox name with possible wildcards reference name
mailbox name with possible wildcards
Arguments (extended): selection options (OPTIONAL) Arguments (extended):
reference name selection options (OPTIONAL)
mailbox patterns reference name
return options (OPTIONAL) mailbox patterns
return options (OPTIONAL)
Responses: untagged responses: LIST Responses: untagged responses: LIST
Result: OK - list completed Result: OK - list completed
NO - list failure: can't list that reference or mailbox NO - list failure: can't list that reference or
name mailbox name
BAD - command unknown or arguments invalid BAD - command unknown or arguments invalid
The LIST command returns a subset of mailbox names from the complete The LIST command returns a subset of mailbox names from the complete
set of all mailbox names available to the client. Zero or more set of all mailbox names available to the client. Zero or more
untagged LIST responses are returned, containing the name attributes, untagged LIST responses are returned, containing the name attributes,
hierarchy delimiter, name, and possible extension information; see hierarchy delimiter, name, and possible extension information; see
the description of the LIST response (Section 7.3.1) for more detail. the description of the LIST response (Section 7.3.1) for more detail.
The LIST command SHOULD return its data quickly, without undue delay. The LIST command SHOULD return its data quickly, without undue delay.
For example, it should not go to excess trouble to calculate the For example, it should not go to excess trouble to calculate the
\Marked or \Unmarked status or perform other processing; if each name \Marked or \Unmarked status or perform other processing; if each name
requires 1 second of processing, then a list of 1200 names would take requires 1 second of processing, then a list of 1200 names would take
20 minutes! 20 minutes!
The extended LIST command, originally introduced in [RFC5258], The extended LIST command, originally introduced in [RFC5258],
provides capabilities beyond that of the original IMAP LIST command. provides capabilities beyond that of the original IMAP LIST command.
The extended syntax is being used if one or more of the following The extended syntax is being used if one or more of the following
conditions is true: conditions is true:
1. if the first word after the command name begins with a 1. the first word after the command name begins with a parenthesis
parenthesis ("LIST selection options"); ("LIST selection options");
2. if the second word after the command name begins with a 2. the second word after the command name begins with a parenthesis;
parenthesis; and
3. if the LIST command has more than 2 parameters ("LIST return 3. the LIST command has more than 2 parameters ("LIST return
options") options").
An empty ("" string) reference name argument indicates that the An empty ("" string) reference name argument indicates that the
mailbox name is interpreted as by SELECT. The returned mailbox names mailbox name is interpreted as by SELECT. The returned mailbox names
MUST match the supplied mailbox name pattern(s). A non-empty MUST match the supplied mailbox name pattern(s). A non-empty
reference name argument is the name of a mailbox or a level of reference name argument is the name of a mailbox or a level of
mailbox hierarchy, and indicates the context in which the mailbox mailbox hierarchy, and it indicates the context in which the mailbox
name is interpreted. Clients SHOULD use the empty reference name is interpreted. Clients SHOULD use the empty reference
argument. argument.
In the basic syntax only, an empty ("" string) mailbox name argument In the basic syntax only, an empty ("" string) mailbox name argument
is a special request to return the hierarchy delimiter and the root is a special request to return the hierarchy delimiter and the root
name of the name given in the reference. The value returned as the name of the name given in the reference. The value returned as the
root MAY be the empty string if the reference is non-rooted or is an root MAY be the empty string if the reference is non-rooted or is an
empty string. In all cases, a hierarchy delimiter (or NIL if there empty string. In all cases, a hierarchy delimiter (or NIL if there
is no hierarchy) is returned. This permits a client to get the is no hierarchy) is returned. This permits a client to get the
hierarchy delimiter (or find out that the mailbox names are flat) hierarchy delimiter (or find out that the mailbox names are flat)
even when no mailboxes by that name currently exist. even when no mailboxes by that name currently exist.
In the extended syntax, any mailbox name arguments that are empty In the extended syntax, any mailbox name arguments that are empty
strings are ignored. There is no special meaning for empty mailbox strings are ignored. There is no special meaning for empty mailbox
names when the extended syntax is used. names when the extended syntax is used.
The reference and mailbox name arguments are interpreted into a The reference and mailbox name arguments are interpreted into a
canonical form that represents an unambiguous left-to-right canonical form that represents an unambiguous left-to-right
hierarchy. The returned mailbox names will be in the interpreted hierarchy. The returned mailbox names will be in the interpreted
form, that we call "canonical LIST pattern" later in this document. form, which we call a "canonical LIST pattern": the canonical pattern
To define the term "canonical LIST pattern" formally: it refers to constructed internally by the server from the reference and mailbox
the canonical pattern constructed internally by the server from the name arguments.
reference and mailbox name arguments.
Note: The interpretation of the reference argument is Note: The interpretation of the reference argument is
implementation-defined. It depends upon whether the server implementation defined. It depends on whether the server
implementation has a concept of the "current working directory" implementation has a concept of the "current working directory"
and leading "break out characters", which override the current and leading "break out characters", which override the current
working directory. working directory.
For example, on a server which exports a UNIX or NT filesystem, For example, on a server that exports a UNIX or NT file system,
the reference argument contains the current working directory, and the reference argument contains the current working directory, and
the mailbox name argument would contain the name as interpreted in the mailbox name argument contains the name as interpreted in the
the current working directory. current working directory.
If a server implementation has no concept of break out characters, If a server implementation has no concept of break out characters,
the canonical form is normally the reference name appended with the canonical form is normally the reference name appended with
the mailbox name. Note that if the server implements the the mailbox name. Note that if the server implements the
namespace convention (Section 5.1.2.1), "#" is a break out namespace convention (Section 5.1.2.1), "#" is a break out
character and must be treated as such. character and must be treated as such.
If the reference argument is not a level of mailbox hierarchy If the reference argument is not a level of mailbox hierarchy
(that is, it is a \NoInferiors name), and/or the reference (that is, it is a \NoInferiors name), and/or the reference
argument does not end with the hierarchy delimiter, it is argument does not end with the hierarchy delimiter, it is
implementation-dependent how this is interpreted. For example, a interpreted as implementation dependent. For example, a reference
reference of "foo/bar" and mailbox name of "rag/baz" could be of "foo/bar" and mailbox name of "rag/baz" could be interpreted as
interpreted as "foo/bar/rag/baz", "foo/barrag/baz", or "foo/rag/ "foo/bar/rag/baz", "foo/barrag/baz", or "foo/rag/baz". A client
baz". A client SHOULD NOT use such a reference argument except at SHOULD NOT use such a reference argument except at the explicit
the explicit request of the user. A hierarchical browser MUST NOT request of the user. A hierarchical browser MUST NOT make any
make any assumptions about server interpretation of the reference assumptions about server interpretation of the reference unless
unless the reference is a level of mailbox hierarchy AND ends with the reference is a level of mailbox hierarchy AND ends with the
the hierarchy delimiter. hierarchy delimiter.
Any part of the reference argument that is included in the Any part of the reference argument that is included in the
interpreted form SHOULD prefix the interpreted form. It SHOULD also interpreted form SHOULD prefix the interpreted form. It SHOULD also
be in the same form as the reference name argument. This rule be in the same form as the reference name argument. This rule
permits the client to determine if the returned mailbox name is in permits the client to determine if the returned mailbox name is in
the context of the reference argument, or if something about the the context of the reference argument or if something about the
mailbox argument overrode the reference argument. Without this rule, mailbox argument overrode the reference argument. Without this rule,
the client would have to have knowledge of the server's naming the client would have to have knowledge of the server's naming
semantics including what characters are "breakouts" that override a semantics including what characters are "breakouts" that override a
naming context. naming context.
Here are some examples of how references Here are some examples of how references and mailbox names might be
and mailbox names might be interpreted on a UNIX-based interpreted on a UNIX-based server:
server:
Reference Mailbox Name Interpretation +==============+==============+===================+
------------ ------------ -------------- | Reference | Mailbox Name | Interpretation |
~smith/Mail/ foo.* ~smith/Mail/foo.* +==============+==============+===================+
archive/ % archive/% | ~smith/Mail/ | foo.* | ~smith/Mail/foo.* |
#news. comp.mail.* #news.comp.mail.* +--------------+--------------+-------------------+
~smith/Mail/ /usr/doc/foo /usr/doc/foo | archive/ | % | archive/% |
archive/ ~fred/Mail/* ~fred/Mail/* +--------------+--------------+-------------------+
| #news. | comp.mail.* | #news.comp.mail.* |
+--------------+--------------+-------------------+
| ~smith/Mail/ | /usr/doc/foo | /usr/doc/foo |
+--------------+--------------+-------------------+
| archive/ | ~fred/Mail/* | ~fred/Mail/* |
+--------------+--------------+-------------------+
The first three examples demonstrate interpretations in Table 1
the context of the reference argument. Note that
"~smith/Mail" SHOULD NOT be transformed into something
like "/u2/users/smith/Mail", or it would be impossible
for the client to determine that the interpretation was
in the context of the reference.
The character "*" is a wildcard, and matches zero or more characters The first three examples above demonstrate interpretations in the
context of the reference argument. Note that "~smith/Mail" SHOULD
NOT be transformed into something like "/u2/users/smith/Mail", or it
would be impossible for the client to determine that the
interpretation was in the context of the reference.
The character "*" is a wildcard and matches zero or more characters
at this position. The character "%" is similar to "*", but it does at this position. The character "%" is similar to "*", but it does
not match a hierarchy delimiter. If the "%" wildcard is the last not match a hierarchy delimiter. If the "%" wildcard is the last
character of a mailbox name argument, matching levels of hierarchy character of a mailbox name argument, matching levels of hierarchy
are also returned. If these levels of hierarchy are not also are also returned. If these levels of hierarchy are not also
selectable mailboxes, they are returned with the \Noselect mailbox selectable mailboxes, they are returned with the \Noselect mailbox
name attribute (see the description of the LIST response name attribute (see the description of the LIST response
(Section 7.3.1) for more details). (Section 7.3.1) for more details).
Any syntactically valid pattern that is not accepted by a server for Any syntactically valid pattern that is not accepted by a server for
any reason MUST be silently ignored. I.e. it results in no LIST any reason MUST be silently ignored, i.e., it results in no LIST
responses and the LIST command still returns tagged OK response. responses, and the LIST command still returns a tagged OK response.
Selection options tell the server to limit the mailbox names that are Selection options tell the server to limit the mailbox names that are
selected by the LIST operation. If selection options are used, the selected by the LIST operation. If selection options are used, the
mailboxes returned are those that match both the list of canonical mailboxes returned are those that match both the list of canonical
LIST patterns and the selection options. Unless a particular LIST patterns and the selection options. Unless a particular
selection option provides special rules, the selection options are selection option provides special rules, the selection options are
cumulative: a mailbox that matches the mailbox patterns is selected cumulative: a mailbox that matches the mailbox patterns is selected
only if it also matches all of the selection options. (An example of only if it also matches all of the selection options. (An example of
a selection option with special rules is the RECURSIVEMATCH option.) a selection option with special rules is the RECURSIVEMATCH option.)
skipping to change at page 51, line 37 skipping to change at line 2402
string (one capability may enable multiple options), and a client string (one capability may enable multiple options), and a client
MUST NOT send an option for which the server has not advertised MUST NOT send an option for which the server has not advertised
support. A server MUST respond to options it does not recognize with support. A server MUST respond to options it does not recognize with
a BAD response. The client SHOULD NOT specify any option more than a BAD response. The client SHOULD NOT specify any option more than
once; however, if the client does this, the server MUST act as if it once; however, if the client does this, the server MUST act as if it
received the option only once. The order in which options are received the option only once. The order in which options are
specified by the client is not significant. specified by the client is not significant.
In general, each selection option except RECURSIVEMATCH will have a In general, each selection option except RECURSIVEMATCH will have a
corresponding return option with the same name. The REMOTE selection corresponding return option with the same name. The REMOTE selection
option is an anomaly in this regard, and does not have a option is an anomaly in this regard and does not have a corresponding
corresponding return option. That is because it expands, rather than return option. That is because it expands, rather than restricts,
restricts, the set of mailboxes that are returned. Future extensions the set of mailboxes that are returned. Future extensions to this
to this specification should keep this parallelism in mind and define specification should keep this parallelism in mind and define a pair
a pair of corresponding selection and return options. of corresponding selection and return options.
Server implementations are permitted to "hide" otherwise accessible Server implementations are permitted to "hide" otherwise accessible
mailboxes from the wildcard characters, by preventing certain mailboxes from the wildcard characters, by preventing certain
characters or names from matching a wildcard in certain situations. characters or names from matching a wildcard in certain situations.
For example, a UNIX-based server might restrict the interpretation of For example, a UNIX-based server might restrict the interpretation of
"*" so that an initial "/" character does not match. "*" so that an initial "/" character does not match.
The special name INBOX is included in the output from LIST, if INBOX The special name INBOX is included in the output from LIST, if INBOX
is supported by this server for this user and if the uppercase string is supported by this server for this user and if the uppercase string
"INBOX" matches the interpreted reference and mailbox name arguments "INBOX" matches the interpreted reference and mailbox name arguments
with wildcards as described above. The criteria for omitting INBOX with wildcards as described above. The criteria for omitting INBOX
is whether SELECT INBOX will return failure; it is not relevant is whether SELECT INBOX will return a failure; it is not relevant
whether the user's real INBOX resides on this or some other server. whether the user's real INBOX resides on this or some other server.
6.3.9.1. LIST Selection Options 6.3.9.1. LIST Selection Options
The selection options defined in this specification are as follows: The selection options defined in this specification are as follows:
SUBSCRIBED - causes the LIST command to list subscribed names, SUBSCRIBED
rather than the existing mailboxes. This will often be a subset Causes the LIST command to list subscribed names rather than the
of the actual mailboxes. It's also possible for this list to existing mailboxes. This will often be a subset of the actual
contain the names of mailboxes that don't exist. In any case, the mailboxes. It's also possible for this list to contain the names
list MUST include exactly those mailbox names that match the of mailboxes that don't exist. In any case, the list MUST include
canonical list pattern and are subscribed to. exactly those mailbox names that match the canonical list pattern
and are subscribed to.
This option defines a mailbox attribute, "\Subscribed", that This option defines a mailbox attribute, "\Subscribed", that
indicates that a mailbox name is subscribed to. The "\Subscribed" indicates that a mailbox name is subscribed to. The "\Subscribed"
attribute MUST be supported and MUST be accurately computed when attribute MUST be supported and MUST be accurately computed when
the SUBSCRIBED selection option is specified. the SUBSCRIBED selection option is specified.
Note that the SUBSCRIBED selection option implies the SUBSCRIBED Note that the SUBSCRIBED selection option implies the SUBSCRIBED
return option (see below). return option (see below).
REMOTE - causes the LIST command to show remote mailboxes as well as REMOTE
local ones, as described in [RFC2193]. This option is intended to Causes the LIST command to show remote mailboxes as well as local
ones, as described in [RFC2193]. This option is intended to
replace the RLIST command and, in conjunction with the SUBSCRIBED replace the RLIST command and, in conjunction with the SUBSCRIBED
selection option, the RLSUB command. Servers that don't support selection option, the RLSUB command. Servers that don't support
the concept of remote mailboxes just ignore this option. the concept of remote mailboxes can ignore this option.
This option defines a mailbox attribute, "\Remote", that indicates This option defines a mailbox attribute, "\Remote", that indicates
that a mailbox is a remote mailbox. The "\Remote" attribute MUST that a mailbox is a remote mailbox. The "\Remote" attribute MUST
be accurately computed when the REMOTE option is specified. be accurately computed when the REMOTE option is specified.
The REMOTE selection option has no interaction with other options. The REMOTE selection option has no interaction with other options.
Its effect is to tell the server to apply the other options, if Its effect is to tell the server to apply the other options, if
any, to remote mailboxes, in addition to local ones. In any, to remote mailboxes, in addition to local ones. In
particular, it has no interaction with RECURSIVEMATCH (see below). particular, it has no interaction with RECURSIVEMATCH (see below).
A request for (REMOTE RECURSIVEMATCH) is invalid, because a A request for (REMOTE RECURSIVEMATCH) is invalid, because a
request for (RECURSIVEMATCH) is also invalid. A request for request for (RECURSIVEMATCH) is also invalid. A request for
(REMOTE RECURSIVEMATCH SUBSCRIBED) is asking for all subscribed (REMOTE RECURSIVEMATCH SUBSCRIBED) is asking for all subscribed
mailboxes, both local and remote. mailboxes, both local and remote.
RECURSIVEMATCH - this option forces the server to return information RECURSIVEMATCH
about parent mailboxes that don't match other selection options, Forces the server to return information about parent mailboxes
but have some submailboxes that do. Information about children is that don't match other selection options but have some
returned in the CHILDINFO extended data item, as described in submailboxes that do. Information about children is returned in
Section 6.3.9.6. the CHILDINFO extended data item, as described in Section 6.3.9.6.
Note 1: In order for a parent mailbox to be returned, it still has Note 1: In order for a parent mailbox to be returned, it still
to match the canonical LIST pattern. has to match the canonical LIST pattern.
Note 2: When returning the CHILDINFO extended data item, it Note 2: When returning the CHILDINFO extended data item, it
doesn't matter whether or not the submailbox matches the canonical doesn't matter whether or not the submailbox matches the
LIST pattern. See also example 9 in Section 6.3.9.8. canonical LIST pattern. See also Example 9 in Section 6.3.9.8.
The RECURSIVEMATCH option MUST NOT occur as the only selection The RECURSIVEMATCH option MUST NOT occur as the only selection
option (or only with REMOTE), as it only makes sense when other option (or only with REMOTE), as it only makes sense when other
selection options are also used. The server MUST return BAD selection options are also used. The server MUST return a BAD
tagged response in such case. tagged response in such case.
Note that even if the RECURSIVEMATCH option is specified, the Note that even if the RECURSIVEMATCH option is specified, the
client MUST still be able to handle a case when a CHILDINFO client MUST still be able to handle cases when a CHILDINFO
extended data item is returned and there are no submailboxes that extended data item is returned and there are no submailboxes that
meet the selection criteria of the subsequent LIST command, as meet the selection criteria of the subsequent LIST command, as
they can be deleted/renamed after the LIST response was sent, but they can be deleted/renamed after the LIST response was sent but
before the client had a chance to access them. before the client had a chance to access them.
6.3.9.2. LIST Return Options 6.3.9.2. LIST Return Options
The return options defined in this specification are as follows: The return options defined in this specification are as follows:
SUBSCRIBED - causes the LIST command to return subscription state SUBSCRIBED
for all matching mailbox names. The "\Subscribed" attribute MUST Causes the LIST command to return subscription state for all
be supported and MUST be accurately computed when the SUBSCRIBED matching mailbox names. The "\Subscribed" attribute MUST be
return option is specified. Further, all other mailbox attributes supported and MUST be accurately computed when the SUBSCRIBED
MUST be accurately computed (this differs from the behavior of the return option is specified. Furthermore, all other mailbox
obsolete LSUB command from RFC 3501). Note that the above attributes MUST be accurately computed (this differs from the
requirements don't override the requirement for the LIST command behavior of the obsolete LSUB command from [RFC3501]). Note that
to return results quickly (see Section 6.3.9), i.e. server the above requirements don't override the requirement for the LIST
implementations need to compute results quickly and accurately. command to return results quickly (see Section 6.3.9), i.e.,
For example, server implementors might need to create quick access server implementations need to compute results quickly and
indices. accurately. For example, server implementors might need to create
quick access indices.
CHILDREN - requests mailbox child information as originally proposed CHILDREN
in [RFC3348]. See Section 6.3.9.5, below, for details. Requests mailbox child information as originally proposed in
[RFC3348]. See Section 6.3.9.5, below, for details.
STATUS - requests STATUS response for each matching mailbox. STATUS
Requests STATUS response for each matching mailbox.
This option takes STATUS data items as parameters. For each This option takes STATUS data items as parameters. For each
selectable mailbox matching the list pattern and selection selectable mailbox matching the list pattern and selection
options, the server MUST return an untagged LIST response options, the server MUST return an untagged LIST response followed
followed by an untagged STATUS response containing the by an untagged STATUS response containing the information
information requested in the STATUS return option, except for requested in the STATUS return option, except for some cases
some cases described below. described below.
If an attempted STATUS for a listed mailbox fails because the If an attempted STATUS for a listed mailbox fails because the
mailbox can't be selected (e.g., if the "l" ACL right [RFC4314] mailbox can't be selected (e.g., if the "l" Access Control List
is granted to the mailbox and the "r" right is not granted, or (ACL) right [RFC4314] is granted to the mailbox and the "r" right
due to a race condition between LIST and STATUS changing the is not granted, or is due to a race condition between LIST and
mailbox to \NoSelect), the STATUS response MUST NOT be returned STATUS changing the mailbox to \NoSelect), the STATUS response
and the LIST response MUST include the \NoSelect attribute. MUST NOT be returned, and the LIST response MUST include the
This means the server may have to buffer the LIST reply until \NoSelect attribute. This means the server may have to buffer the
it has successfully looked up the necessary STATUS information. LIST reply until it has successfully looked up the necessary
STATUS information.
If the server runs into unexpected problems while trying to If the server runs into unexpected problems while trying to look
look up the STATUS information, it MAY drop the corresponding up the STATUS information, it MAY drop the corresponding STATUS
STATUS reply. In such a situation, the LIST command would reply. In such a situation, the LIST command would still return a
still return a tagged OK reply. tagged OK reply.
See the note in the discussion of the STATUS command in
Section 6.3.11 for information about obtaining status on the
currently selected mailbox.
6.3.9.3. General Principles for Returning LIST Responses 6.3.9.3. General Principles for Returning LIST Responses
This section outlines several principles that can be used by server This section outlines several principles that can be used by server
implementations of this document to decide whether a LIST response implementations of this document to decide whether a LIST response
should be returned, as well as how many responses and what kind of should be returned, as well as how many responses and what kind of
information they may contain. information they may contain.
1. At most one LIST response should be returned for each mailbox 1. At most, one LIST response should be returned for each mailbox
name that matches the canonical LIST pattern. Server name that matches the canonical LIST pattern. Server
implementors must not assume that clients will be able to implementors must not assume that clients will be able to
assemble mailbox attributes and other information returned in assemble mailbox attributes and other information returned in
multiple LIST responses. multiple LIST responses.
2. There are only two reasons for including a matching mailbox name 2. There are only two reasons for including a matching mailbox name
in the responses to the LIST command (note that the server is in the responses to the LIST command (note that the server is
allowed to return unsolicited responses at any time, and such allowed to return unsolicited responses at any time, and such
responses are not governed by this rule): responses are not governed by this rule):
skipping to change at page 54, line 52 skipping to change at line 2569
LIST pattern. LIST pattern.
For more information on this case, see the CHILDINFO extended For more information on this case, see the CHILDINFO extended
data item described in Section 6.3.9.6. Note that the data item described in Section 6.3.9.6. Note that the
CHILDINFO extended data item can only be returned when the CHILDINFO extended data item can only be returned when the
RECURSIVEMATCH selection option is specified. RECURSIVEMATCH selection option is specified.
3. Attributes returned in the same LIST response are treated 3. Attributes returned in the same LIST response are treated
additively. For example, the following response additively. For example, the following response
S: * LIST (\Subscribed \NonExistent) "/" "Fruit/Peach" S: * LIST (\Subscribed \NonExistent) "/" "Fruit/Peach"
means that the "Fruit/Peach" mailbox doesn't exist, but it is means that the "Fruit/Peach" mailbox doesn't exist, but it is
subscribed. subscribed.
6.3.9.4. Additional LIST-related Requirements on Clients 6.3.9.4. Additional LIST-Related Requirements on Clients
All clients MUST treat a LIST attribute with a stronger meaning as All clients MUST treat a LIST attribute with a stronger meaning as
implying any attribute that can be inferred from it. (See implying any attribute that can be inferred from it. (See
Section 7.3.1 for the list of currently defined attributes). For Section 7.3.1 for the list of currently defined attributes.) For
example, the client must treat the presence of the \NoInferiors example, the client must treat the presence of the \NoInferiors
attribute as if the \HasNoChildren attribute was also sent by the attribute as if the \HasNoChildren attribute was also sent by the
server. server.
The following table summarizes inference rules. The following table summarizes inference rules.
+--------------------+-------------------+ +====================+===================+
| returned attribute | implied attribute | | returned attribute | implied attribute |
+--------------------+-------------------+ +====================+===================+
| \NoInferiors | \HasNoChildren | | \NoInferiors | \HasNoChildren |
+--------------------+-------------------+
| \NonExistent | \NoSelect | | \NonExistent | \NoSelect |
+--------------------+-------------------+ +--------------------+-------------------+
Table 2
6.3.9.5. The CHILDREN Return Option 6.3.9.5. The CHILDREN Return Option
The CHILDREN return option is simply an indication that the client The CHILDREN return option is simply an indication that the client
wants information about whether or not mailboxes contain children wants information about whether or not mailboxes contain child
mailboxes; a server MAY provide it even if the option is not mailboxes; a server MAY provide it even if the option is not
specified. specified.
Many IMAP4 clients present to the user a hierarchical view of the Many IMAP clients present the user with a hierarchical view of the
mailboxes that a user has access to. Rather than initially mailboxes that a user has access to. Rather than initially
presenting to the user the entire mailbox hierarchy, it is often presenting the entire mailbox hierarchy to the user, it is often
preferable to show to the user a collapsed outline list of the preferable to show the user a collapsed outline list of the mailbox
mailbox hierarchy (particularly if there is a large number of hierarchy (particularly if there is a large number of mailboxes).
mailboxes). The user can then expand the collapsed outline hierarchy The user can then expand the collapsed outline hierarchy as needed.
as needed. It is common to include within the collapsed hierarchy a It is common to include a visual clue (such as a ''+'') within the
visual clue (such as a ''+'') to indicate that there are child collapsed hierarchy to indicate that there are child mailboxes under
mailboxes under a particular mailbox. When the visual clue is a particular mailbox. When the visual clue is clicked, the hierarchy
clicked, the hierarchy list is expanded to show the child mailboxes. list is expanded to show the child mailboxes. The CHILDREN return
The CHILDREN return option provides a mechanism for a client to option provides a mechanism for a client to efficiently determine
efficiently determine whether a particular mailbox has children, whether a particular mailbox has children, without issuing a LIST ""
without issuing a LIST "" * or a LIST "" % for each mailbox name. * or a LIST "" % for each mailbox name. The CHILDREN return option
The CHILDREN return option defines two new attributes that MUST be defines two new attributes that MUST be returned within a LIST
returned within a LIST response: \HasChildren and \HasNoChildren. response: \HasChildren and \HasNoChildren. Although these attributes
Although these attributes MAY be returned in response to any LIST MAY be returned in response to any LIST command, the CHILDREN return
command, the CHILDREN return option is provided to indicate that the option is provided to indicate that the client particularly wants
client particularly wants this information. If the CHILDREN return this information. If the CHILDREN return option is present, the
option is present, the server MUST return these attributes even if server MUST return these attributes even if their computation is
their computation is expensive. expensive.
\HasChildren \HasChildren
The presence of this attribute indicates that the mailbox has The presence of this attribute indicates that the mailbox has
child mailboxes. A server SHOULD NOT set this attribute if child mailboxes. A server SHOULD NOT set this attribute if
there are child mailboxes and the user does not have permission there are child mailboxes and the user does not have permission
to access any of them. In this case, \HasNoChildren SHOULD be to access any of them. In this case, \HasNoChildren SHOULD be
used. In many cases, however, a server may not be able to used. In many cases, however, a server may not be able to
efficiently compute whether a user has access to any child efficiently compute whether a user has access to any child
mailbox. Note that even though the \HasChildren attribute for a mailbox. Note that even though the \HasChildren attribute for a
mailbox must be correct at the time of processing of the mailbox must be correct at the time of processing the mailbox, a
mailbox, a client must be prepared to deal with a situation when client must be prepared to deal with a situation when a mailbox
a mailbox is marked with the \HasChildren attribute, but no is marked with the \HasChildren attribute, but no child mailbox
child mailbox appears in the response to the LIST command. This appears in the response to the LIST command. This might happen,
might happen, for example, due to children mailboxes being for example, due to child mailboxes being deleted or made
deleted or made inaccessible to the user (using access control) inaccessible to the user (using access control) by another
by another client before the server is able to list them. client before the server is able to list them.
\HasNoChildren \HasNoChildren
The presence of this attribute indicates that the mailbox has NO The presence of this attribute indicates that the mailbox has NO
child mailboxes that are accessible to the currently child mailboxes that are accessible to the currently
authenticated user. authenticated user.
It is an error for the server to return both a \HasChildren and a It is an error for the server to return both a \HasChildren and a
\HasNoChildren attribute in the same LIST response. \HasNoChildren attribute in the same LIST response.
Note: the \HasNoChildren attribute should not be confused with the Note: the \HasNoChildren attribute should not be confused with the
the \NoInferiors attribute, which indicates that no child mailboxes \NoInferiors attribute, which indicates that no child mailboxes exist
exist now and none can be created in the future. now and none can be created in the future.
6.3.9.6. CHILDINFO Extended Data Item 6.3.9.6. CHILDINFO Extended Data Item
The CHILDINFO extended data item MUST NOT be returned unless the The CHILDINFO extended data item MUST NOT be returned unless the
client has specified the RECURSIVEMATCH selection option. client has specified the RECURSIVEMATCH selection option.
The CHILDINFO extended data item in a LIST response describes the The CHILDINFO extended data item in a LIST response describes the
selection criteria that has caused it to be returned and indicates selection criteria that has caused it to be returned and indicates
that the mailbox has at least one descendant mailbox that matches the that the mailbox has at least one descendant mailbox that matches the
selection criteria. selection criteria.
Note: Some servers allow for mailboxes to exist without requiring Note: Some servers allow for mailboxes to exist without requiring
their parent to exist. For example, a mailbox "Customers/ABC" can their parent to exist. For example, the mailbox "Customers/ABC" can
exist while the mailbox "Customers" does not. As CHILDINFO extended exist while the mailbox "Customers" does not. As the CHILDINFO
data item is not allowed if the RECURSIVEMATCH selection option is extended data item is not allowed if the RECURSIVEMATCH selection
not specified, such servers SHOULD use the "\NonExistent option is not specified, such servers SHOULD use the "\NonExistent
\HasChildren" attribute pair to signal to the client that there is a \HasChildren" attribute pair to signal to the client that there is a
descendant mailbox that matches the selection criteria. See example descendant mailbox that matches the selection criteria. See Example
11 in Section 6.3.9.8. 11 in Section 6.3.9.8.
The returned selection criteria allow the client to distinguish a The returned selection criteria allows the client to distinguish a
solicited response from an unsolicited one, as well as to distinguish solicited response from an unsolicited one, as well as to distinguish
among solicited responses caused by multiple pipelined LIST commands among solicited responses caused by multiple pipelined LIST commands
that specify different criteria. that specify different criteria.
Servers SHOULD only return a non-matching mailbox name along with Servers SHOULD only return a non-matching mailbox name along with
CHILDINFO if at least one matching child is not also being returned. CHILDINFO if at least one matching child is not also being returned.
That is, servers SHOULD suppress redundant CHILDINFO responses. That is, servers SHOULD suppress redundant CHILDINFO responses.
Examples 8 and 10 in Section 6.3.9.8 demonstrate the difference Examples 8 and 10 in Section 6.3.9.8 demonstrate the difference
between present CHILDINFO extended data item and the "\HasChildren" between the present CHILDINFO extended data item and the
attribute. "\HasChildren" attribute.
The following table summarizes interaction between the "\NonExistent" The following table summarizes interaction between the "\NonExistent"
attribute and CHILDINFO (the first column indicates whether the attribute and CHILDINFO (the first column indicates whether the
parent mailbox exists): parent mailbox exists):
+--------+-------------+------------------+-------------------------+ +========+===========+====================+=====================+
| exists | meets the | has a child that | returned | | Exists | Meets the | Has a child that | Returned IMAP4rev2/ |
| | selection | meets the | IMAP4rev2/LIST-EXTENDED | | | selection | meets the | LIST-EXTENDED |
| | criteria | selection | attributes and | | | criteria | selection criteria | attributes and |
| | | criteria | CHILDINFO | | | | | CHILDINFO |
+--------+-------------+------------------+-------------------------+ +========+===========+====================+=====================+
| no | no | no | no LIST response | | no | no | no | no LIST response |
| | | | returned | | | | | returned |
| yes | no | no | no LIST response | +--------+-----------+--------------------+---------------------+
| | | | returned | | yes | no | no | no LIST response |
| no | yes | no | (\NonExistent <attr>) | | | | | returned |
| yes | yes | no | (<attr>) | +--------+-----------+--------------------+---------------------+
| no | no | yes | (\NonExistent) + | | no | yes | no | (\NonExistent |
| | | | CHILDINFO | | | | | <attr>) |
| yes | no | yes | () + CHILDINFO | +--------+-----------+--------------------+---------------------+
| no | yes | yes | (\NonExistent <attr>) + | | yes | yes | no | (<attr>) |
| | | | CHILDINFO | +--------+-----------+--------------------+---------------------+
| yes | yes | yes | (<attr>) + CHILDINFO | | no | no | yes | (\NonExistent) + |
+--------+-------------+------------------+-------------------------+ | | | | CHILDINFO |
+--------+-----------+--------------------+---------------------+
| yes | no | yes | () + CHILDINFO |
+--------+-----------+--------------------+---------------------+
| no | yes | yes | (\NonExistent |
| | | | <attr>) + CHILDINFO |
+--------+-----------+--------------------+---------------------+
| yes | yes | yes | (<attr>) + |
| | | | CHILDINFO |
+--------+-----------+--------------------+---------------------+
where <attr> is one or more attributes that correspond to the Table 3
selection criteria; for example, for the SUBSCRIBED option the <attr>
is \Subscribed. where <attr> is one or more attributes that correspond to the
selection criteria; for example, for the SUBSCRIBED option, the
<attr> is \Subscribed.
6.3.9.7. OLDNAME Extended Data Item 6.3.9.7. OLDNAME Extended Data Item
The OLDNAME extended data item is included when a mailbox name is The OLDNAME extended data item is included when a mailbox name is
created (with CREATE command), renamed (with RENAME command) or created (with the CREATE command), renamed (with the RENAME command),
deleted (with DELETE command). (When a mailbox is deleted the or deleted (with the DELETE command). (When a mailbox is deleted,
"\NonExistent" attribute is also included.) IMAP extensions can the "\NonExistent" attribute is also included.) IMAP extensions can
specify other conditions when OLDNAME extended data item should be specify other conditions when the OLDNAME extended data item should
included. be included.
If the server allows de-normalized mailbox names (see Section 5.1) in If the server allows denormalized mailbox names (see Section 5.1) in
SELECT/EXAMINE, CREATE, RENAME or DELETE, it SHOULD return an SELECT/EXAMINE, CREATE, RENAME, or DELETE, it SHOULD return an
unsolicited LIST response that includes OLDNAME extended data item, unsolicited LIST response that includes the OLDNAME extended data
whenever the supplied mailbox name differs from the resulting item, whenever the supplied mailbox name differs from the resulting
normalized mailbox name. From the client point of view this is normalized mailbox name. From the client point of view, this is
indistinguishable from another user renaming or deleting the mailbox, indistinguishable from another user renaming or deleting the mailbox,
as specified in the previous paragraph. as specified in the previous paragraph.
A deleted mailbox can be announced like this: A deleted mailbox can be announced as follows:
S: * LIST (\NonExistent) "." "INBOX.DeletedMailbox" S: * LIST (\NonExistent) "." "INBOX.DeletedMailbox"
Example of a renamed mailbox: Example of a renamed mailbox:
S: * LIST () "/" "NewMailbox" ("OLDNAME" ("OldMailbox")) S: * LIST () "/" "NewMailbox" ("OLDNAME" ("OldMailbox"))
6.3.9.8. LIST Command Examples 6.3.9.8. LIST Command Examples
This example shows some uses of the basic LIST command: This example shows some uses of the basic LIST command:
Example: C: A101 LIST "" "" Example:
S: * LIST (\Noselect) "/" ""
S: A101 OK LIST Completed C: A101 LIST "" ""
C: A102 LIST #news.comp.mail.misc "" S: * LIST (\Noselect) "/" ""
S: * LIST (\Noselect) "." #news. S: A101 OK LIST Completed
S: A102 OK LIST Completed C: A102 LIST #news.comp.mail.misc ""
C: A103 LIST /usr/staff/jones "" S: * LIST (\Noselect) "." #news.
S: * LIST (\Noselect) "/" / S: A102 OK LIST Completed
S: A103 OK LIST Completed C: A103 LIST /usr/staff/jones ""
C: A202 LIST ~/Mail/ % S: * LIST (\Noselect) "/" /
S: * LIST (\Noselect) "/" ~/Mail/foo S: A103 OK LIST Completed
S: * LIST () "/" ~/Mail/meetings C: A202 LIST ~/Mail/ %
S: A202 OK LIST completed S: * LIST (\Noselect) "/" ~/Mail/foo
S: * LIST () "/" ~/Mail/meetings
S: A202 OK LIST completed
Extended examples: Extended examples:
1: The first example shows the complete local hierarchy that will 1: The first example shows the complete local hierarchy that will
be used for the other examples. be used for the other examples.
C: A01 LIST "" "*" C: A01 LIST "" "*"
S: * LIST (\Marked \NoInferiors) "/" "inbox" S: * LIST (\Marked \NoInferiors) "/" "inbox"
S: * LIST () "/" "Fruit" S: * LIST () "/" "Fruit"
S: * LIST () "/" "Fruit/Apple" S: * LIST () "/" "Fruit/Apple"
S: * LIST () "/" "Fruit/Banana" S: * LIST () "/" "Fruit/Banana"
S: * LIST () "/" "Tofu" S: * LIST () "/" "Tofu"
S: * LIST () "/" "Vegetable" S: * LIST () "/" "Vegetable"
S: * LIST () "/" "Vegetable/Broccoli" S: * LIST () "/" "Vegetable/Broccoli"
S: * LIST () "/" "Vegetable/Corn" S: * LIST () "/" "Vegetable/Corn"
S: A01 OK done S: A01 OK done
2: In the next example, we will see the subscribed mailboxes. This 2: In the next example, we will see the subscribed mailboxes. This
is similar to, but not equivalent with now deprecated, <LSUB "" is similar to, but not equivalent with, the now deprecated <LSUB
"*"> (see [RFC3501] for more details on LSUB command). Note "" "*"> (see [RFC3501] for more details on the LSUB command).
that the mailbox called "Fruit/Peach" is subscribed to, but does Note that the mailbox called "Fruit/Peach" is subscribed to, but
not actually exist (perhaps it was deleted while still it does not actually exist (perhaps it was deleted while still
subscribed). The "Fruit" mailbox is not subscribed to, but it subscribed). The "Fruit" mailbox is not subscribed to, but it
has two subscribed children. The "Vegetable" mailbox is has two subscribed children. The "Vegetable" mailbox is
subscribed and has two children; one of them is subscribed as subscribed and has two children; one of them is subscribed as
well. well.
C: A02 LIST (SUBSCRIBED) "" "*" C: A02 LIST (SUBSCRIBED) "" "*"
S: * LIST (\Marked \NoInferiors \Subscribed) "/" "inbox" S: * LIST (\Marked \NoInferiors \Subscribed) "/" "inbox"
S: * LIST (\Subscribed) "/" "Fruit/Banana" S: * LIST (\Subscribed) "/" "Fruit/Banana"
S: * LIST (\Subscribed \NonExistent) "/" "Fruit/Peach" S: * LIST (\Subscribed \NonExistent) "/" "Fruit/Peach"
S: * LIST (\Subscribed) "/" "Vegetable" S: * LIST (\Subscribed) "/" "Vegetable"
S: * LIST (\Subscribed) "/" "Vegetable/Broccoli" S: * LIST (\Subscribed) "/" "Vegetable/Broccoli"
S: A02 OK done S: A02 OK done
3: The next example shows the use of the CHILDREN option. The 3: The next example shows the use of the CHILDREN option. The
client, without having to list the second level of hierarchy, client, without having to list the second level of hierarchy,
now knows which of the top-level mailboxes have submailboxes now knows which of the top-level mailboxes have submailboxes
(children) and which do not. Note that it's not necessary for (children) and which do not. Note that it's not necessary for
the server to return the \HasNoChildren attribute for the inbox, the server to return the \HasNoChildren attribute for the inbox,
because the \NoInferiors attribute already implies that, and has because the \NoInferiors attribute already implies that and has
a stronger meaning. a stronger meaning.
C: A03 LIST () "" "%" RETURN (CHILDREN) C: A03 LIST () "" "%" RETURN (CHILDREN)
S: * LIST (\Marked \NoInferiors) "/" "inbox" S: * LIST (\Marked \NoInferiors) "/" "inbox"
S: * LIST (\HasChildren) "/" "Fruit" S: * LIST (\HasChildren) "/" "Fruit"
S: * LIST (\HasNoChildren) "/" "Tofu" S: * LIST (\HasNoChildren) "/" "Tofu"
S: * LIST (\HasChildren) "/" "Vegetable" S: * LIST (\HasChildren) "/" "Vegetable"
S: A03 OK done S: A03 OK done
4: In this example, we see more mailboxes that reside on another 4: In this example, we see more mailboxes that reside on another
server. This is similar to the command <RLIST "" "%">. server. This is similar to the command <RLIST "" "%">.
C: A04 LIST (REMOTE) "" "%" RETURN (CHILDREN) C: A04 LIST (REMOTE) "" "%" RETURN (CHILDREN)
S: * LIST (\Marked \NoInferiors) "/" "inbox" S: * LIST (\Marked \NoInferiors) "/" "inbox"
S: * LIST (\HasChildren) "/" "Fruit" S: * LIST (\HasChildren) "/" "Fruit"
S: * LIST (\HasNoChildren) "/" "Tofu" S: * LIST (\HasNoChildren) "/" "Tofu"
S: * LIST (\HasChildren) "/" "Vegetable" S: * LIST (\HasChildren) "/" "Vegetable"
S: * LIST (\Remote \HasNoChildren) "/" "Bread" S: * LIST (\Remote \HasNoChildren) "/" "Bread"
S: * LIST (\HasChildren \Remote) "/" "Meat" S: * LIST (\HasChildren \Remote) "/" "Meat"
S: A04 OK done S: A04 OK done
5: The following example also requests the server to include 5: The following example also requests the server to include
mailboxes that reside on another server. The server returns mailboxes that reside on another server. The server returns
information about all mailboxes that are subscribed. This is information about all mailboxes that are subscribed. This is
similar to the command <RLSUB "" "*"> (see [RFC2193] for more similar to the command <RLSUB "" "*"> (see [RFC2193] for more
details on RLSUB). We also see the use of two selection details on RLSUB). We also see the use of two selection
options. options.
C: A05 LIST (REMOTE SUBSCRIBED) "" "*" C: A05 LIST (REMOTE SUBSCRIBED) "" "*"
S: * LIST (\Marked \NoInferiors \Subscribed) "/" "inbox" S: * LIST (\Marked \NoInferiors \Subscribed) "/" "inbox"
S: * LIST (\Subscribed) "/" "Fruit/Banana" S: * LIST (\Subscribed) "/" "Fruit/Banana"
S: * LIST (\Subscribed \NonExistent) "/" "Fruit/Peach" S: * LIST (\Subscribed \NonExistent) "/" "Fruit/Peach"
S: * LIST (\Subscribed) "/" "Vegetable" S: * LIST (\Subscribed) "/" "Vegetable"
S: * LIST (\Subscribed) "/" "Vegetable/Broccoli" S: * LIST (\Subscribed) "/" "Vegetable/Broccoli"
S: * LIST (\Remote \Subscribed) "/" "Bread" S: * LIST (\Remote \Subscribed) "/" "Bread"
S: A05 OK done S: A05 OK done
6: The following example requests the server to include mailboxes 6: The following example requests the server to include mailboxes
that reside on another server. The server is asked to return that reside on another server. The server is asked to return
subscription information for all returned mailboxes. This is subscription information for all returned mailboxes. This is
different from the example above. different from the example above.
Note that the output of this command is not a superset of the Note that the output of this command is not a superset of the
output in the previous example, as it doesn't include LIST output in the previous example, as it doesn't include a LIST
response for the non-existent "Fruit/Peach". response for the non-existent "Fruit/Peach".
C: A06 LIST (REMOTE) "" "*" RETURN (SUBSCRIBED) C: A06 LIST (REMOTE) "" "*" RETURN (SUBSCRIBED)
S: * LIST (\Marked \NoInferiors \Subscribed) "/" "inbox" S: * LIST (\Marked \NoInferiors \Subscribed) "/" "inbox"
S: * LIST () "/" "Fruit" S: * LIST () "/" "Fruit"
S: * LIST () "/" "Fruit/Apple" S: * LIST () "/" "Fruit/Apple"
S: * LIST (\Subscribed) "/" "Fruit/Banana" S: * LIST (\Subscribed) "/" "Fruit/Banana"
S: * LIST () "/" "Tofu" S: * LIST () "/" "Tofu"
S: * LIST (\Subscribed) "/" "Vegetable" S: * LIST (\Subscribed) "/" "Vegetable"
S: * LIST (\Subscribed) "/" "Vegetable/Broccoli" S: * LIST (\Subscribed) "/" "Vegetable/Broccoli"
S: * LIST () "/" "Vegetable/Corn" S: * LIST () "/" "Vegetable/Corn"
S: * LIST (\Remote \Subscribed) "/" "Bread" S: * LIST (\Remote \Subscribed) "/" "Bread"
S: * LIST (\Remote) "/" "Meat" S: * LIST (\Remote) "/" "Meat"
S: A06 OK done S: A06 OK done
7: The following example demonstrates the difference between the 7: The following example demonstrates the difference between the
\HasChildren attribute and the CHILDINFO extended data item. \HasChildren attribute and the CHILDINFO extended data item.
Let's assume there is the following hierarchy: Let's assume there is the following hierarchy:
C: C01 LIST "" "*" C: C01 LIST "" "*"
S: * LIST (\Marked \NoInferiors) "/" "inbox" S: * LIST (\Marked \NoInferiors) "/" "inbox"
S: * LIST () "/" "Foo" S: * LIST () "/" "Foo"
S: * LIST () "/" "Foo/Bar" S: * LIST () "/" "Foo/Bar"
S: * LIST () "/" "Foo/Baz" S: * LIST () "/" "Foo/Baz"
S: * LIST () "/" "Moo" S: * LIST () "/" "Moo"
S: C01 OK done S: C01 OK done
If the client asks RETURN (CHILDREN), it will get this: If the client asks RETURN (CHILDREN), it will get this:
C: CA3 LIST "" "%" RETURN (CHILDREN) C: CA3 LIST "" "%" RETURN (CHILDREN)
S: * LIST (\Marked \NoInferiors) "/" "inbox" S: * LIST (\Marked \NoInferiors) "/" "inbox"
S: * LIST (\HasChildren) "/" "Foo" S: * LIST (\HasChildren) "/" "Foo"
S: * LIST (\HasNoChildren) "/" "Moo" S: * LIST (\HasNoChildren) "/" "Moo"
S: CA3 OK done S: CA3 OK done
A) Let's also assume that the mailbox "Foo/Baz" is the only A) Let's also assume that the mailbox "Foo/Baz" is the only
subscribed mailbox. Then we get this result: subscribed mailbox. Then we get this result:
C: C02 LIST (SUBSCRIBED) "" "*" C: C02 LIST (SUBSCRIBED) "" "*"
S: * LIST (\Subscribed) "/" "Foo/Baz" S: * LIST (\Subscribed) "/" "Foo/Baz"
S: C02 OK done S: C02 OK done
Now, if the client issues <LIST (SUBSCRIBED) "" "%">, the server Now, if the client issues <LIST (SUBSCRIBED) "" "%">, the
will return no mailboxes (as the mailboxes "Moo", "Foo", and server will return no mailboxes (as the mailboxes "Moo",
"Inbox" are NOT subscribed). However, if the client issues "Foo", and "Inbox" are NOT subscribed). However, if the
this: client issues this:
C: C04 LIST (SUBSCRIBED RECURSIVEMATCH) "" "%" C: C04 LIST (SUBSCRIBED RECURSIVEMATCH) "" "%"
S: * LIST () "/" "Foo" ("CHILDINFO" ("SUBSCRIBED")) S: * LIST () "/" "Foo" ("CHILDINFO" ("SUBSCRIBED"))
S: C04 OK done S: C04 OK done
(i.e., the mailbox "Foo" is not subscribed, but it has a child (that is, the mailbox "Foo" is not subscribed, but it has a
that is.) child that is), then A1 or A2 occurs.
A1) If the mailbox "Foo" had also been subscribed, the last A1) If the mailbox "Foo" had also been subscribed, the last
command would return this: command would return this:
C: C04 LIST (SUBSCRIBED RECURSIVEMATCH) "" "%" C: C04 LIST (SUBSCRIBED RECURSIVEMATCH) "" "%"
S: * LIST (\Subscribed) "/" "Foo" ("CHILDINFO" ("SUBSCRIBED")) S: * LIST (\Subscribed) "/" "Foo" ("CHILDINFO"
S: C04 OK done ("SUBSCRIBED"))
S: C04 OK done
or even this: or even this:
C: C04 LIST (SUBSCRIBED RECURSIVEMATCH) "" "%" C: C04 LIST (SUBSCRIBED RECURSIVEMATCH) "" "%"
S: * LIST (\Subscribed \HasChildren) "/" "Foo" ("CHILDINFO" S: * LIST (\Subscribed \HasChildren) "/" "Foo"
("SUBSCRIBED")) ("CHILDINFO" ("SUBSCRIBED"))
S: C04 OK done S: C04 OK done
A2) If we assume instead that the mailbox "Foo" is not part of A2) If we assume instead that the mailbox "Foo" is not part
the original hierarchy and is not subscribed, the last command of the original hierarchy and is not subscribed, the
will give this result: last command will give this result:
C: C04 LIST (SUBSCRIBED RECURSIVEMATCH) "" "%" C: C04 LIST (SUBSCRIBED RECURSIVEMATCH) "" "%"
S: * LIST (\NonExistent) "/" "Foo" ("CHILDINFO" ("SUBSCRIBED")) S: * LIST (\NonExistent) "/" "Foo" ("CHILDINFO"
S: C04 OK done ("SUBSCRIBED"))
S: C04 OK done
B) Now, let's assume that no mailbox is subscribed. In this B) Now, let's assume that no mailbox is subscribed. In this
case, the command <LIST (SUBSCRIBED RECURSIVEMATCH) "" "%"> will case, the command <LIST (SUBSCRIBED RECURSIVEMATCH) "" "%">
return no responses, as there are no subscribed children (even will return no responses, as there are no subscribed
though "Foo" has children). children (even though "Foo" has children).
C) And finally, suppose that only the mailboxes "Foo" and "Moo" C) And finally, suppose that only the mailboxes "Foo" and "Moo"
are subscribed. In that case, we see this result: are subscribed. In that case, we see this result:
C: C04 LIST (SUBSCRIBED RECURSIVEMATCH) "" "%" RETURN (CHILDREN) C: C04 LIST (SUBSCRIBED RECURSIVEMATCH) "" "%" RETURN
S: * LIST (\HasChildren \Subscribed) "/" "Foo" (CHILDREN)
S: * LIST (\HasNoChildren \Subscribed) "/" "Moo" S: * LIST (\HasChildren \Subscribed) "/" "Foo"
S: C04 OK done S: * LIST (\HasNoChildren \Subscribed) "/" "Moo"
S: C04 OK done
(which means that the mailbox "Foo" has children, but none of (which means that the mailbox "Foo" has children, but none
them is subscribed). of them is subscribed).
8: The following example demonstrates that the CHILDINFO extended 8: The following example demonstrates that the CHILDINFO extended
data item is returned whether or not children mailboxes match data item is returned whether or not child mailboxes match the
the canonical LIST pattern. canonical LIST pattern.
Let's assume there is the following hierarchy: Let's assume there is the following hierarchy:
C: D01 LIST "" "*" C: D01 LIST "" "*"
S: * LIST (\Marked \NoInferiors) "/" "inbox" S: * LIST (\Marked \NoInferiors) "/" "inbox"
S: * LIST () "/" "foo2" S: * LIST () "/" "foo2"
S: * LIST () "/" "foo2/bar1" S: * LIST () "/" "foo2/bar1"
S: * LIST () "/" "foo2/bar2" S: * LIST () "/" "foo2/bar2"
S: * LIST () "/" "baz2" S: * LIST () "/" "baz2"
S: * LIST () "/" "baz2/bar2" S: * LIST () "/" "baz2/bar2"
S: * LIST () "/" "baz2/bar22" S: * LIST () "/" "baz2/bar22"
S: * LIST () "/" "baz2/bar222" S: * LIST () "/" "baz2/bar222"
S: * LIST () "/" "eps2" S: * LIST () "/" "eps2"
S: * LIST () "/" "eps2/mamba" S: * LIST () "/" "eps2/mamba"
S: * LIST () "/" "qux2/bar2" S: * LIST () "/" "qux2/bar2"
S: D01 OK done S: D01 OK done
And that the following mailboxes are subscribed: And that the following mailboxes are subscribed:
C: D02 LIST (SUBSCRIBED) "" "*" C: D02 LIST (SUBSCRIBED) "" "*"
S: * LIST (\Subscribed) "/" "foo2/bar1" S: * LIST (\Subscribed) "/" "foo2/bar1"
S: * LIST (\Subscribed) "/" "foo2/bar2" S: * LIST (\Subscribed) "/" "foo2/bar2"
S: * LIST (\Subscribed) "/" "baz2/bar2" S: * LIST (\Subscribed) "/" "baz2/bar2"
S: * LIST (\Subscribed) "/" "baz2/bar22" S: * LIST (\Subscribed) "/" "baz2/bar22"
S: * LIST (\Subscribed) "/" "baz2/bar222" S: * LIST (\Subscribed) "/" "baz2/bar222"
S: * LIST (\Subscribed) "/" "eps2" S: * LIST (\Subscribed) "/" "eps2"
S: * LIST (\Subscribed) "/" "eps2/mamba" S: * LIST (\Subscribed) "/" "eps2/mamba"
S: * LIST (\Subscribed) "/" "qux2/bar2" S: * LIST (\Subscribed) "/" "qux2/bar2"
S: D02 OK done S: D02 OK done
The client issues the following command first: The client issues the following command first:
C: D03 LIST (RECURSIVEMATCH SUBSCRIBED) "" "*2" C: D03 LIST (RECURSIVEMATCH SUBSCRIBED) "" "*2"
S: * LIST () "/" "foo2" ("CHILDINFO" ("SUBSCRIBED")) S: * LIST () "/" "foo2" ("CHILDINFO" ("SUBSCRIBED"))
S: * LIST (\Subscribed) "/" "foo2/bar2" S: * LIST (\Subscribed) "/" "foo2/bar2"
S: * LIST (\Subscribed) "/" "baz2/bar2" S: * LIST (\Subscribed) "/" "baz2/bar2"
S: * LIST (\Subscribed) "/" "baz2/bar22" S: * LIST (\Subscribed) "/" "baz2/bar22"
S: * LIST (\Subscribed) "/" "baz2/bar222" S: * LIST (\Subscribed) "/" "baz2/bar222"
S: * LIST (\Subscribed) "/" "eps2" ("CHILDINFO" ("SUBSCRIBED")) S: * LIST (\Subscribed) "/" "eps2" ("CHILDINFO" ("SUBSCRIBED"))
S: * LIST (\Subscribed) "/" "qux2/bar2" S: * LIST (\Subscribed) "/" "qux2/bar2"
S: D03 OK done S: D03 OK done
and the server may also include (but this would violate a SHOULD and the server may also include the following (but this would
NOT in Section 3.5, because CHILDINFO is redundant) violate a restriction in Section 6.3.9.6, because CHILDINFO is
redundant):
S: * LIST () "/" "baz2" ("CHILDINFO" ("SUBSCRIBED")) S: * LIST () "/" "baz2" ("CHILDINFO" ("SUBSCRIBED"))
S: * LIST (\NonExistent) "/" "qux2" ("CHILDINFO" ("SUBSCRIBED")) S: * LIST (\NonExistent) "/" "qux2" ("CHILDINFO" ("SUBSCRIBED"))
The CHILDINFO extended data item is returned for mailboxes The CHILDINFO extended data item is returned for mailboxes
"foo2", "baz2", and "eps2", because all of them have subscribed "foo2", "baz2", and "eps2" because all of them have subscribed
children, even though for the mailbox "foo2" only one of the two children, even though for the mailbox "foo2", only one of the
subscribed children matches the pattern, for the mailbox "baz2" two subscribed children matches the pattern; for the mailbox
all the subscribed children match the pattern, and for the "baz2", all of the subscribed children match the pattern; and
mailbox "eps2" none of the subscribed children matches the for the mailbox "eps2", none of the subscribed children match
pattern. the pattern.
Note that if the client issues Note that if the client issues the following:
C: D03 LIST (RECURSIVEMATCH SUBSCRIBED) "" "*" C: D03 LIST (RECURSIVEMATCH SUBSCRIBED) "" "*"
S: * LIST () "/" "foo2" ("CHILDINFO" ("SUBSCRIBED")) S: * LIST () "/" "foo2" ("CHILDINFO" ("SUBSCRIBED"))
S: * LIST (\Subscribed) "/" "foo2/bar1" S: * LIST (\Subscribed) "/" "foo2/bar1"
S: * LIST (\Subscribed) "/" "foo2/bar2" S: * LIST (\Subscribed) "/" "foo2/bar2"
S: * LIST () "/" "baz2" ("CHILDINFO" ("SUBSCRIBED")) S: * LIST () "/" "baz2" ("CHILDINFO" ("SUBSCRIBED"))
S: * LIST (\Subscribed) "/" "baz2/bar2" S: * LIST (\Subscribed) "/" "baz2/bar2"
S: * LIST (\Subscribed) "/" "baz2/bar22" S: * LIST (\Subscribed) "/" "baz2/bar22"
S: * LIST (\Subscribed) "/" "baz2/bar222" S: * LIST (\Subscribed) "/" "baz2/bar222"
S: * LIST (\Subscribed) "/" "eps2" ("CHILDINFO" ("SUBSCRIBED")) S: * LIST (\Subscribed) "/" "eps2" ("CHILDINFO" ("SUBSCRIBED"))
S: * LIST (\Subscribed) "/" "eps2/mamba" S: * LIST (\Subscribed) "/" "eps2/mamba"
S: * LIST (\Subscribed) "/" "qux2/bar2" S: * LIST (\Subscribed) "/" "qux2/bar2"
S: D03 OK done S: D03 OK done
The LIST responses for mailboxes "foo2", "baz2", and "eps2" the LIST responses for mailboxes "foo2", "baz2", and "eps2"
still have the CHILDINFO extended data item, even though this still have the CHILDINFO extended data item, even though this
information is redundant and the client can determine it by information is redundant and the client can determine it by
itself. itself.
9: The following example shows usage of extended syntax for mailbox 9: The following example shows usage of an extended syntax for the
pattern. It also demonstrates that the presence of the mailbox pattern. It also demonstrates that the presence of the
CHILDINFO extended data item doesn't necessarily imply CHILDINFO extended data item doesn't necessarily imply
\HasChildren. \HasChildren.
C: a1 LIST "" ("foo") C: a1 LIST "" ("foo")
S: * LIST () "/" foo S: * LIST () "/" foo
S: a1 OK done S: a1 OK done
C: a2 LIST (SUBSCRIBED) "" "foo/*" C: a2 LIST (SUBSCRIBED) "" "foo/*"
S: * LIST (\Subscribed \NonExistent) "/" foo/bar S: * LIST (\Subscribed \NonExistent) "/" foo/bar
S: a2 OK done S: a2 OK done
C: a3 LIST (SUBSCRIBED RECURSIVEMATCH) "" foo RETURN (CHILDREN) C: a3 LIST (SUBSCRIBED RECURSIVEMATCH) "" foo RETURN (CHILDREN)
S: * LIST (\HasNoChildren) "/" foo ("CHILDINFO" ("SUBSCRIBED")) S: * LIST (\HasNoChildren) "/" foo ("CHILDINFO" ("SUBSCRIBED"))
S: a3 OK done S: a3 OK done
10: The following example shows how a server that supports missing 10: The following example shows how a server that supports missing
mailbox hierarchy elements can signal to a client that didn't mailbox hierarchy elements can signal to a client that didn't
specify the RECURSIVEMATCH selection option that there is a specify the RECURSIVEMATCH selection option that there is a
child mailbox that matches the selection criteria. child mailbox that matches the selection criteria.
C: a1 LIST (REMOTE) "" * C: a1 LIST (REMOTE) "" *
S: * LIST () "/" music/rock S: * LIST () "/" music/rock
S: * LIST (\Remote) "/" also/jazz S: * LIST (\Remote) "/" also/jazz
S: a1 OK done S: a1 OK done
C: a2 LIST () "" % C: a2 LIST () "" %
S: * LIST (\NonExistent \HasChildren) "/" music S: * LIST (\NonExistent \HasChildren) "/" music
S: a2 OK done S: a2 OK done
C: a3 LIST (REMOTE) "" % C: a3 LIST (REMOTE) "" %
S: * LIST (\NonExistent \HasChildren) "/" music S: * LIST (\NonExistent \HasChildren) "/" music
S: * LIST (\NonExistent \HasChildren) "/" also S: * LIST (\NonExistent \HasChildren) "/" also
S: a3 OK done S: a3 OK done
C: a3.1 LIST "" (% music/rock) C: a3.1 LIST "" (% music/rock)
S: * LIST () "/" music/rock S: * LIST () "/" music/rock
S: a3.1 OK done S: a3.1 OK done
Because "music/rock" is the only mailbox under "music", there's Because "music/rock" is the only mailbox under "music", there's
no need for the server to also return "music". However clients no need for the server to also return "music". However, clients
must handle both cases. must handle both cases.
11: The following examples show use of STATUS return option. 11: The following examples show use of the STATUS return option.
C: A01 LIST "" % RETURN (STATUS (MESSAGES UNSEEN)) C: A01 LIST "" % RETURN (STATUS (MESSAGES UNSEEN))
S: * LIST () "." "INBOX" S: * LIST () "." "INBOX"
S: * STATUS "INBOX" (MESSAGES 17 UNSEEN 16) S: * STATUS "INBOX" (MESSAGES 17 UNSEEN 16)
S: * LIST () "." "foo" S: * LIST () "." "foo"
S: * STATUS "foo" (MESSAGES 30 UNSEEN 29) S: * STATUS "foo" (MESSAGES 30 UNSEEN 29)
S: * LIST (\NoSelect) "." "bar" S: * LIST (\NoSelect) "." "bar"
S: A01 OK List completed. S: A01 OK List completed.
The "bar" mailbox isn't selectable, so it has no STATUS reply. The "bar" mailbox isn't selectable, so it has no STATUS reply.
C: A02 LIST (SUBSCRIBED RECURSIVEMATCH) "" % RETURN (STATUS C: A02 LIST (SUBSCRIBED RECURSIVEMATCH) "" % RETURN (STATUS
(MESSAGES)) (MESSAGES))
S: * LIST (\Subscribed) "." "INBOX" S: * LIST (\Subscribed) "." "INBOX"
S: * STATUS "INBOX" (MESSAGES 17) S: * STATUS "INBOX" (MESSAGES 17)
S: * LIST () "." "foo" (CHILDINFO ("SUBSCRIBED")) S: * LIST () "." "foo" (CHILDINFO ("SUBSCRIBED"))
S: A02 OK List completed. S: A02 OK List completed.
The LIST reply for "foo" is returned because it has matching The LIST reply for "foo" is returned because it has matching
children, but no STATUS reply is returned because "foo" itself children, but no STATUS reply is returned because "foo" itself
doesn't match the selection criteria. doesn't match the selection criteria.
6.3.10. NAMESPACE Command 6.3.10. NAMESPACE Command
Arguments: none Arguments: none
Responses: REQUIRED untagged responses: NAMESPACE Responses: REQUIRED untagged responses: NAMESPACE
Result: OK - command completed Result: OK - command completed
NO - Can't complete the command NO - Can't complete the command
BAD - arguments invalid BAD - arguments invalid
The NAMESPACE command causes a single untagged NAMESPACE response to The NAMESPACE command causes a single untagged NAMESPACE response to
be returned. The untagged NAMESPACE response contains the prefix and be returned. The untagged NAMESPACE response contains the prefix and
hierarchy delimiter to the server's Personal Namespace(s), Other hierarchy delimiter to the server's Personal Namespace(s), Other
Users' Namespace(s), and Shared Namespace(s) that the server wishes Users' Namespace(s), and Shared Namespace(s) that the server wishes
to expose. The response will contain a NIL for any namespace class to expose. The response will contain a NIL for any namespace class
that is not available. The namespace-response-extensions ABNF non that is not available. The namespace-response-extensions ABNF non-
terminal is defined for extensibility and MAY be included in the terminal is defined for extensibility and MAY be included in the
NAMESPACE response. NAMESPACE response.
Example 1: Example 1:
In this example a server supports a single personal namespace. No In this example, a server supports a single Personal Namespace. No
leading prefix is used on personal mailboxes and "/" is the hierarchy leading prefix is used on personal mailboxes, and "/" is the
delimiter. hierarchy delimiter.
C: A001 NAMESPACE C: A001 NAMESPACE
S: * NAMESPACE (("" "/")) NIL NIL S: * NAMESPACE (("" "/")) NIL NIL
S: A001 OK NAMESPACE command completed S: A001 OK NAMESPACE command completed
Example 2: Example 2:
A user logged on anonymously to a server. No personal mailboxes are A user logged on anonymously to a server. No personal mailboxes are
associated with the anonymous user and the user does not have access associated with the anonymous user, and the user does not have access
to the Other Users' Namespace. No prefix is required to access to the Other Users' Namespace. No prefix is required to access
shared mailboxes and the hierarchy delimiter is "." shared mailboxes, and the hierarchy delimiter is "."
C: A001 NAMESPACE C: A001 NAMESPACE
S: * NAMESPACE NIL NIL (("" ".")) S: * NAMESPACE NIL NIL (("" "."))
S: A001 OK NAMESPACE command completed S: A001 OK NAMESPACE command completed
Example 3: Example 3:
A server that contains a Personal Namespace and a single Shared A server that contains a Personal Namespace and a single Shared
Namespace. Namespace.
C: A001 NAMESPACE C: A001 NAMESPACE
S: * NAMESPACE (("" "/")) NIL (("Public Folders/" "/")) S: * NAMESPACE (("" "/")) NIL (("Public Folders/" "/"))
S: A001 OK NAMESPACE command completed S: A001 OK NAMESPACE command completed
Example 4: Example 4:
A server that contains a Personal Namespace, Other Users' Namespace A server that contains a Personal Namespace, Other Users' Namespace,
and multiple Shared Namespaces. Note that the hierarchy delimiter and multiple Shared Namespaces. Note that the hierarchy delimiter
used within each namespace can be different. used within each namespace can be different.
C: A001 NAMESPACE C: A001 NAMESPACE
S: * NAMESPACE (("" "/")) (("~" "/")) (("#shared/" "/") S: * NAMESPACE (("" "/")) (("~" "/")) (("#shared/" "/")
("#public/" "/")("#ftp/" "/")("#news." ".")) ("#public/" "/")("#ftp/" "/")("#news." "."))
S: A001 OK NAMESPACE command completed S: A001 OK NAMESPACE command completed
The prefix string allows a client to do things such as automatically The prefix string allows a client to do things such as automatically
creating personal mailboxes or LISTing all available mailboxes within create personal mailboxes or LIST all available mailboxes within a
a namespace. namespace.
Example 5: Example 5:
A server that supports only the Personal Namespace, with a leading A server that supports only the Personal Namespace, with a leading
prefix of INBOX to personal mailboxes and a hierarchy delimiter of prefix of INBOX to personal mailboxes and a hierarchy delimiter of
"." ".".
C: A001 NAMESPACE C: A001 NAMESPACE
S: * NAMESPACE (("INBOX." ".")) NIL NIL S: * NAMESPACE (("INBOX." ".")) NIL NIL
S: A001 OK NAMESPACE command completed S: A001 OK NAMESPACE command completed
< Automatically create a mailbox to store sent items.> Automatically create a mailbox to store sent items.
C: A002 CREATE "INBOX.Sent Mail" C: A002 CREATE "INBOX.Sent Mail"
S: A002 OK CREATE command completed S: A002 OK CREATE command completed
Although typically a server will support only a single Personal Although a server will typically support only a single Personal
Namespace, and a single Other User's Namespace, circumstances exist Namespace, and a single Other User's Namespace, circumstances exist
where there MAY be multiples of these, and a client MUST be prepared where there MAY be multiples of these, and a client MUST be prepared
for them. If a client is configured such that it is required to for them. If a client is configured such that it is required to
create a certain mailbox, there can be circumstances where it is create a certain mailbox, there can be circumstances where it is
unclear which Personal Namespaces it should create the mailbox in. unclear which Personal Namespaces it should create the mailbox in.
In these situations a client SHOULD let the user select which In these situations, a client SHOULD let the user select which
namespaces to create the mailbox in or just use the first personal namespaces to create the mailbox in, or just use the first Personal
namespace. Namespace.
Example 6: Example 6:
In this example, a server supports two Personal Namespaces. In In this example, a server supports two Personal Namespaces. In
addition to the regular Personal Namespace, the user has an addition to the regular Personal Namespace, the user has an
additional personal namespace to allow access to mailboxes in an MH additional Personal Namespace that allows access to mailboxes in an
format mailstore. MH format mailstore.
The client is configured to save a copy of all mail sent by the user The client is configured to save a copy of all mail sent by the user
into a mailbox with the \Sent attribute (see Section 7.3.1). into a mailbox with the \Sent attribute (see Section 7.3.1).
Furthermore, after a message is deleted from a mailbox, the client is Furthermore, after a message is deleted from a mailbox, the client is
configured to move that message to a mailbox with the \Trash configured to move that message to a mailbox with the \Trash
attribute. The server signals with the \NonExistent mailbox attribute. The server signals with the \NonExistent mailbox
attribute that the corresponding mailboxes don't exist yet, and that attribute that the corresponding mailboxes don't exist yet and that
it is possible to create them. Once created, they could be used for it is possible to create them. Once created, they could be used for
the \Sent or \Trash purposes and the server will no longer include \Sent or \Trash purposes, and the server will no longer include the
the \NonExistent mailbox attribute for them. \NonExistent mailbox attribute for them.
Note that this example demonstrates how some extension parameters can Note that this example demonstrates how some extension parameters can
be passed to further describe the #mh namespace. See the fictitious be passed to further describe the #mh namespace. See the fictitious
"X-PARAM" extension parameter. "X-PARAM" extension parameter.
C: A001 NAMESPACE C: A001 NAMESPACE
S: * NAMESPACE (("" "/")("#mh/" "/" "X-PARAM" S: * NAMESPACE (("" "/")("#mh/" "/" "X-PARAM"
("FLAG1" "FLAG2"))) NIL NIL ("FLAG1" "FLAG2"))) NIL NIL
S: A001 OK NAMESPACE command completed S: A001 OK NAMESPACE command completed
C: A002 LIST (SPECIAL-USE) "" "*" C: A002 LIST (SPECIAL-USE) "" "*"
S: * LIST (\NonExistent \Archive) "/" Archives S: * LIST (\NonExistent \Archive) "/" Archives
S: * LIST (\NonExistent \Drafts) "/" Drafts S: * LIST (\NonExistent \Drafts) "/" Drafts
S: * LIST (\NonExistent \Junk) "/" Junk S: * LIST (\NonExistent \Junk) "/" Junk
S: * LIST (\NonExistent \Sent) "/" "Sent Mail" S: * LIST (\NonExistent \Sent) "/" "Sent Mail"
S: * LIST (\NonExistent \Trash) "/" "Deleted Items" S: * LIST (\NonExistent \Trash) "/" "Deleted Items"
S: A002 OK LIST Completed S: A002 OK LIST Completed
C: A003 LIST (SPECIAL-USE) "#mh/" "*" C: A003 LIST (SPECIAL-USE) "#mh/" "*"
S: * LIST (\NonExistent \Archive) "/" "#mh/Archives" S: * LIST (\NonExistent \Archive) "/" "#mh/Archives"
S: * LIST (\NonExistent \Drafts) "/" "#mh/Drafts" S: * LIST (\NonExistent \Drafts) "/" "#mh/Drafts"
S: * LIST (\NonExistent \Junk) "/" "#mh/Junk" S: * LIST (\NonExistent \Junk) "/" "#mh/Junk"
S: * LIST (\NonExistent \Sent) "/" "#mh/Sent Mail" S: * LIST (\NonExistent \Sent) "/" "#mh/Sent Mail"
S: * LIST (\NonExistent \Trash) "/" "#mh/Deleted Items" S: * LIST (\NonExistent \Trash) "/" "#mh/Deleted Items"
S: A003 OK LIST Completed S: A003 OK LIST Completed
< It is desired to keep only one copy of sent mail. It is desired to keep only one copy of sent mail. It is unclear
It is unclear which Personal Namespace the client which Personal Namespace the client should use to create the 'Sent
should use to create the 'Sent Mail' mailbox. Mail' mailbox. The user is prompted to select a namespace, and only
The user is prompted to select a namespace and only one 'Sent Mail' mailbox is created.
one 'Sent Mail' mailbox is created. >
C: A004 CREATE "Sent Mail" C: A004 CREATE "Sent Mail"
S: A004 OK CREATE command completed S: A004 OK CREATE command completed
< The client is designed so that it keeps two The client is designed so that it keeps two 'Deleted Items'
'Deleted Items' mailboxes, one for each namespace. > mailboxes, one for each namespace.
C: A005 CREATE "Delete Items" C: A005 CREATE "Delete Items"
S: A005 OK CREATE command completed S: A005 OK CREATE command completed
C: A006 CREATE "#mh/Deleted Items" C: A006 CREATE "#mh/Deleted Items"
S: A006 OK CREATE command completed S: A006 OK CREATE command completed
The next level of hierarchy following the Other Users' Namespace The next level of hierarchy following the Other Users' Namespace
prefix SHOULD consist of <username>, where <username> is a user name prefix SHOULD consist of <username>, where <username> is a user name
as per the LOGIN or AUTHENTICATE command. as per the LOGIN or AUTHENTICATE command.
A client can construct a LIST command by appending a "%" to the Other A client can construct a LIST command by appending a "%" to the Other
Users' Namespace prefix to discover the Personal Namespaces of other Users' Namespace prefix to discover the Personal Namespaces of other
users that are available to the currently authenticated user. users that are available to the currently authenticated user.
In response to such a LIST command, a server SHOULD NOT return user In response to such a LIST command, a server SHOULD NOT return user
skipping to change at page 70, line 21 skipping to change at line 3266
Alternatively, a server MAY return NO to such a LIST command, Alternatively, a server MAY return NO to such a LIST command,
requiring that a user name be included with the Other Users' requiring that a user name be included with the Other Users'
Namespace prefix before listing any other user's mailboxes. Namespace prefix before listing any other user's mailboxes.
Example 7: Example 7:
A server that supports providing a list of other user's mailboxes A server that supports providing a list of other user's mailboxes
that are accessible to the currently logged on user. that are accessible to the currently logged on user.
C: A001 NAMESPACE C: A001 NAMESPACE
S: * NAMESPACE (("" "/")) (("Other Users/" "/")) NIL S: * NAMESPACE (("" "/")) (("Other Users/" "/")) NIL
S: A001 OK NAMESPACE command completed S: A001 OK NAMESPACE command completed
C: A002 LIST "" "Other Users/%" C: A002 LIST "" "Other Users/%"
S: * LIST () "/" "Other Users/Mike" S: * LIST () "/" "Other Users/Mike"
S: * LIST () "/" "Other Users/Karen" S: * LIST () "/" "Other Users/Karen"
S: * LIST () "/" "Other Users/Matthew" S: * LIST () "/" "Other Users/Matthew"
S: * LIST () "/" "Other Users/Tesa" S: * LIST () "/" "Other Users/Tesa"
S: A002 OK LIST command completed S: A002 OK LIST command completed
Example 8: Example 8:
A server that does not support providing a list of other user's A server that does not support providing a list of other user's
mailboxes that are accessible to the currently logged on user. The mailboxes that are accessible to the currently logged on user. The
mailboxes are listable if the client includes the name of the other mailboxes are listable if the client includes the name of the other
user with the Other Users' Namespace prefix. user with the Other Users' Namespace prefix.
C: A001 NAMESPACE C: A001 NAMESPACE
S: * NAMESPACE (("" "/")) (("#Users/" "/")) NIL S: * NAMESPACE (("" "/")) (("#Users/" "/")) NIL
S: A001 OK NAMESPACE command completed S: A001 OK NAMESPACE command completed
< In this example, the currently logged on user has access to In this example, the currently logged on user has access to the
the Personal Namespace of user Mike, but the server chose to Personal Namespace of user Mike, but the server chose to suppress
suppress this information in the LIST response. However, this information in the LIST response. However, by appending the
by appending the user name Mike (received through user input) user name Mike (received through user input) to the Other Users'
to the Other Users' Namespace prefix, the client is able Namespace prefix, the client is able to get a listing of the personal
to get a listing of the personal mailboxes of user Mike. > mailboxes of user Mike.
C: A002 LIST "" "#Users/%" C: A002 LIST "" "#Users/%"
S: A002 NO The requested item could not be found. S: A002 NO The requested item could not be found.
C: A003 LIST "" "#Users/Mike/%" C: A003 LIST "" "#Users/Mike/%"
S: * LIST () "/" "#Users/Mike/INBOX" S: * LIST () "/" "#Users/Mike/INBOX"
S: * LIST () "/" "#Users/Mike/Foo" S: * LIST () "/" "#Users/Mike/Foo"
S: A003 OK LIST command completed. S: A003 OK LIST command completed.
A prefix string might not contain a hierarchy delimiter, because in A prefix string might not contain a hierarchy delimiter, because in
some cases it is not needed as part of the prefix. some cases, it is not needed as part of the prefix.
Example 9: Example 9:
A server that allows access to the Other Users' Namespace by A server that allows access to the Other Users' Namespace by
prefixing the others' mailboxes with a '~' followed by <username>, prefixing the others' mailboxes with a '~' followed by <username>,
where <username> is a user name as per the LOGIN or AUTHENTICATE where <username> is a user name as per the LOGIN or AUTHENTICATE
command. command.
C: A001 NAMESPACE C: A001 NAMESPACE
S: * NAMESPACE (("" "/")) (("~" "/")) NIL S: * NAMESPACE (("" "/")) (("~" "/")) NIL
S: A001 OK NAMESPACE command completed S: A001 OK NAMESPACE command completed
< List the mailboxes for user mark > List the mailboxes for user mark
C: A002 LIST "" "~mark/%" C: A002 LIST "" "~mark/%"
S: * LIST () "/" "~mark/INBOX" S: * LIST () "/" "~mark/INBOX"
S: * LIST () "/" "~mark/foo" S: * LIST () "/" "~mark/foo"
S: A002 OK LIST command completed S: A002 OK LIST command completed
6.3.11. STATUS Command 6.3.11. STATUS Command
Arguments: mailbox name Arguments: mailbox name
status data item names
Responses: REQUIRED untagged responses: STATUS status data item names
Result: OK - status completed Responses: REQUIRED untagged responses: STATUS
NO - status failure: no status for that name
BAD - command unknown or arguments invalid Result: OK - status completed
NO - status failure: no status for that name
BAD - command unknown or arguments invalid
The STATUS command requests the status of the indicated mailbox. It The STATUS command requests the status of the indicated mailbox. It
does not change the currently selected mailbox, nor does it affect does not change the currently selected mailbox, nor does it affect
the state of any messages in the queried mailbox. the state of any messages in the queried mailbox.
The STATUS command provides an alternative to opening a second The STATUS command provides an alternative to opening a second
IMAP4rev2 connection and doing an EXAMINE command on a mailbox to IMAP4rev2 connection and doing an EXAMINE command on a mailbox to
query that mailbox's status without deselecting the current mailbox query that mailbox's status without deselecting the current mailbox
in the first IMAP4rev2 connection. in the first IMAP4rev2 connection.
Unlike the LIST command, the STATUS command is not guaranteed to be Unlike the LIST command, the STATUS command is not guaranteed to be
fast in its response. Under certain circumstances, it can be quite fast in its response. Under certain circumstances, it can be quite
slow. In some implementations, the server is obliged to open the slow. In some implementations, the server is obliged to open the
mailbox read-only internally to obtain certain status information. mailbox as "read-only" internally to obtain certain status
Also unlike the LIST command, the STATUS command does not accept information. Also unlike the LIST command, the STATUS command does
wildcards. not accept wildcards.
Note: The STATUS command is intended to access the status of Note: The STATUS command is intended to access the status of
mailboxes other than the currently selected mailbox. Because the mailboxes other than the currently selected mailbox. Because the
STATUS command can cause the mailbox to be opened internally, and STATUS command can cause the mailbox to be opened internally, and
because this information is available by other means on the because this information is available by other means on the
selected mailbox, the STATUS command SHOULD NOT be used on the selected mailbox, the STATUS command SHOULD NOT be used on the
currently selected mailbox. However, servers MUST be able to currently selected mailbox. However, servers MUST be able to
execute STATUS command on the selected mailbox. (This might also execute the STATUS command on the selected mailbox. (This might
implicitly happen when STATUS return option is used in a LIST also implicitly happen when the STATUS return option is used in a
command). LIST command.)
The STATUS command MUST NOT be used as a "check for new messages The STATUS command MUST NOT be used as a "check for new messages
in the selected mailbox" operation (refer to Section 7 and in the selected mailbox" operation (refer to Sections 7 and 7.4.1
Section 7.4.1 for more information about the proper method for new for more information about the proper method for new message
message checking). checking).
STATUS SIZE (see below) can take a significant amount of time, STATUS SIZE (see below) can take a significant amount of time,
depending upon server implementation. Clients should use STATUS depending upon server implementation. Clients should use STATUS
SIZE cautiously. SIZE cautiously.
The currently defined status data items that can be requested are: The currently defined status data items that can be requested are:
MESSAGES The number of messages in the mailbox. MESSAGES
The number of messages in the mailbox.
UIDNEXT The next unique identifier value of the mailbox. Refer to UIDNEXT
The next unique identifier value of the mailbox. Refer to
Section 2.3.1.1 for more information. Section 2.3.1.1 for more information.
UIDVALIDITY The unique identifier validity value of the mailbox. UIDVALIDITY
Refer to Section 2.3.1.1 for more information. The unique identifier validity value of the mailbox. Refer to
Section 2.3.1.1 for more information.
UNSEEN The number of messages which do not have the \Seen flag set. UNSEEN
The number of messages that do not have the \Seen flag set.
DELETED The number of messages which have the \Deleted flag set. DELETED
The number of messages that have the \Deleted flag set.
SIZE The total size of the mailbox in octets. This is not strictly SIZE
The total size of the mailbox in octets. This is not strictly
required to be an exact value, but it MUST be equal to or greater required to be an exact value, but it MUST be equal to or greater
than the sum of the values of the RFC822.SIZE FETCH message data than the sum of the values of the RFC822.SIZE FETCH message data
items (see Section 6.4.5) of all messages in the mailbox. items (see Section 6.4.5) of all messages in the mailbox.
Example: C: A042 STATUS blurdybloop (UIDNEXT MESSAGES) Example:
S: * STATUS blurdybloop (MESSAGES 231 UIDNEXT 44292)
S: A042 OK STATUS completed C: A042 STATUS blurdybloop (UIDNEXT MESSAGES)
S: * STATUS blurdybloop (MESSAGES 231 UIDNEXT 44292)
S: A042 OK STATUS completed
6.3.12. APPEND Command 6.3.12. APPEND Command
Arguments: mailbox name Arguments: mailbox name
OPTIONAL flag parenthesized list
OPTIONAL date/time string
message literal
Responses: OPTIONAL untagged response: LIST OPTIONAL flag parenthesized list
Result: OK - append completed OPTIONAL date/time string
NO - append error: can't append to that mailbox, error
in flags or date/time or message text message literal
BAD - command unknown or arguments invalid
Responses: OPTIONAL untagged response: LIST
Result: OK - append completed
NO - append error: can't append to that mailbox, error
in flags or date/time or message text
BAD - command unknown or arguments invalid
The APPEND command appends the literal argument as a new message to The APPEND command appends the literal argument as a new message to
the end of the specified destination mailbox. This argument SHOULD the end of the specified destination mailbox. This argument SHOULD
be in the format of an [RFC-5322] or [I18N-HDRS] message. 8-bit be in the format of an [RFC5322] or [I18N-HDRS] message. 8-bit
characters are permitted in the message. A server implementation characters are permitted in the message. A server implementation
that is unable to preserve 8-bit data properly MUST be able to that is unable to preserve 8-bit data properly MUST be able to
reversibly convert 8-bit APPEND data to 7-bit using a [MIME-IMB] reversibly convert 8-bit APPEND data to 7 bits using a [MIME-IMB]
content transfer encoding. content transfer encoding.
Note: There may be exceptions, e.g., draft messages, in which Note: There may be exceptions, such as draft messages, in which
required [RFC-5322] header fields are omitted in the message required [RFC5322] header fields are omitted in the message
literal argument to APPEND. The full implications of doing so literal argument to APPEND. The full implications of doing so
must be understood and carefully weighed. must be understood and carefully weighed.
If a flag parenthesized list is specified, the flags SHOULD be set in If a flag parenthesized list is specified, the flags SHOULD be set in
the resulting message; otherwise, the flag list of the resulting the resulting message; otherwise, the flag list of the resulting
message is set to empty by default. message is set to "empty" by default.
If a date-time is specified, the internal date SHOULD be set in the If a date-time is specified, the internal date SHOULD be set in the
resulting message; otherwise, the internal date of the resulting resulting message; otherwise, the internal date of the resulting
message is set to the current date and time by default. message is set to the current date and time by default.
If the append is unsuccessful for any reason, the mailbox MUST be If the append is unsuccessful for any reason, the mailbox MUST be
restored to its state before the APPEND attempt (other than possibly restored to its state before the APPEND attempt (other than possibly
keeping the changed mailbox's UIDNEXT value); no partial appending is keeping the changed mailbox's UIDNEXT value); no partial appending is
permitted. permitted.
If the destination mailbox does not exist, a server MUST return an If the destination mailbox does not exist, a server MUST return an
error, and MUST NOT automatically create the mailbox. Unless it is error and MUST NOT automatically create the mailbox. Unless it is
certain that the destination mailbox can not be created, the server certain that the destination mailbox cannot be created, the server
MUST send the response code "[TRYCREATE]" as the prefix of the text MUST send the response code "[TRYCREATE]" as the prefix of the text
of the tagged NO response. This gives a hint to the client that it of the tagged NO response. This gives a hint to the client that it
can attempt a CREATE command and retry the APPEND if the CREATE is can attempt a CREATE command and retry the APPEND if the CREATE is
successful. successful.
On successful completion of an APPEND, the server returns an On successful completion of an APPEND, the server returns an
APPENDUID response code (see Section 7.1), unless specified otherwise APPENDUID response code (see Section 7.1), unless otherwise specified
below. below.
In the case of a mailbox that has permissions set so that the client In the case of a mailbox that has permissions set so that the client
can APPEND to the mailbox, but not SELECT or EXAMINE it, the server can APPEND to the mailbox, but not SELECT or EXAMINE it, the server
MUST NOT send an APPENDUID response code as it would disclose MUST NOT send an APPENDUID response code as it would disclose
information about the mailbox. information about the mailbox.
In the case of a mailbox that has UIDNOTSTICKY status (see In the case of a mailbox that has UIDNOTSTICKY status (see
Section 7.1), the server MAY omit the APPENDUID response code as it Section 7.1), the server MAY omit the APPENDUID response code as it
is not meaningful. is not meaningful.
If the mailbox is currently selected, the normal new message actions If the mailbox is currently selected, normal new message actions
SHOULD occur. Specifically, the server SHOULD notify the client SHOULD occur. Specifically, the server SHOULD notify the client
immediately via an untagged EXISTS response. If the server does not immediately via an untagged EXISTS response. If the server does not
do so, the client MAY issue a NOOP command after one or more APPEND do so, the client MAY issue a NOOP command after one or more APPEND
commands. commands.
If the server decides to convert (normalize) the mailbox name, it If the server decides to convert (normalize) the mailbox name, it
SHOULD return an untagged LIST with OLDNAME extended data item, with SHOULD return an untagged LIST with an OLDNAME extended data item,
the OLDNAME value being the supplied mailbox name and the name with the OLDNAME value being the supplied mailbox name and the name
parameter being the normalized mailbox name. (See Section 6.3.9.7 parameter being the normalized mailbox name. (See Section 6.3.9.7
for more details.) for more details.)
Example: C: A003 APPEND saved-messages (\Seen) {326}
S: + Ready for literal data
C: Date: Mon, 7 Feb 1994 21:52:25 -0800 (PST)
C: From: Fred Foobar <foobar@Blurdybloop.example>
C: Subject: afternoon meeting
C: To: mooch@owatagu.siam.edu.example
C: Message-Id: <B27397-0100000@Blurdybloop.example>
C: MIME-Version: 1.0
C: Content-Type: TEXT/PLAIN; CHARSET=US-ASCII
C:
C: Hello Joe, do you think we can meet at 3:30 tomorrow?
C:
S: A003 OK APPEND completed
Example: C: A003 APPEND saved-messages (\Seen) {297+} Example:
C: Date: Mon, 7 Feb 1994 21:52:25 -0800 (PST)
C: From: Fred Foobar <foobar@example.com> C: A003 APPEND saved-messages (\Seen) {326}
C: Subject: afternoon meeting S: + Ready for literal data
C: To: mooch@example.com C: Date: Mon, 7 Feb 1994 21:52:25 -0800 (PST)
C: Message-Id: <B27397-0100000@example.com> C: From: Fred Foobar <foobar@Blurdybloop.example>
C: MIME-Version: 1.0 C: Subject: afternoon meeting
C: Content-Type: TEXT/PLAIN; CHARSET=US-ASCII C: To: mooch@owatagu.siam.edu.example
C: C: Message-Id: <B27397-0100000@Blurdybloop.example>
C: Hello Joe, do you think we can meet at 3:30 tomorrow? C: MIME-Version: 1.0
C: C: Content-Type: TEXT/PLAIN; CHARSET=US-ASCII
S: A003 OK [APPENDUID 38505 3955] APPEND completed C:
C: A004 COPY 2:4 meeting C: Hello Joe, do you think we can meet at 3:30 tomorrow?
S: A004 OK [COPYUID 38505 304,319:320 3956:3958] Done C:
C: A005 UID COPY 305:310 meeting S: A003 OK APPEND completed
S: A005 OK No matching messages, so nothing copied
C: A006 COPY 2 funny Example:
S: A006 OK Done
C: A007 SELECT funny C: A003 APPEND saved-messages (\Seen) {297+}
S: * 1 EXISTS C: Date: Mon, 7 Feb 1994 21:52:25 -0800 (PST)
S: * OK [UIDVALIDITY 3857529045] Validity session-only C: From: Fred Foobar <foobar@example.com>
S: * OK [UIDNEXT 2] Predicted next UID C: Subject: afternoon meeting
S: * NO [UIDNOTSTICKY] Non-persistent UIDs C: To: mooch@example.com
S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft) C: Message-Id: <B27397-0100000@example.com>
S: * OK [PERMANENTFLAGS (\Deleted \Seen)] Limited C: MIME-Version: 1.0
S: * LIST () "." funny C: Content-Type: TEXT/PLAIN; CHARSET=US-ASCII
S: A007 OK [READ-WRITE] SELECT completed C:
C: Hello Joe, do you think we can meet at 3:30 tomorrow?
C:
S: A003 OK [APPENDUID 38505 3955] APPEND completed
C: A004 COPY 2:4 meeting
S: A004 OK [COPYUID 38505 304,319:320 3956:3958] Done
C: A005 UID COPY 305:310 meeting
S: A005 OK No matching messages, so nothing copied
C: A006 COPY 2 funny
S: A006 OK Done
C: A007 SELECT funny
S: * 1 EXISTS
S: * OK [UIDVALIDITY 3857529045] Validity session-only
S: * OK [UIDNEXT 2] Predicted next UID
S: * NO [UIDNOTSTICKY] Non-persistent UIDs
S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
S: * OK [PERMANENTFLAGS (\Deleted \Seen)] Limited
S: * LIST () "." funny
S: A007 OK [READ-WRITE] SELECT completed
In this example, A003 and A004 demonstrate successful appending and In this example, A003 and A004 demonstrate successful appending and
copying to a mailbox that returns the UIDs assigned to the messages. copying to a mailbox that returns the UIDs assigned to the messages.
A005 is an example in which no messages were copied; this is because A005 is an example in which no messages were copied; this is because
in A003, we see that message 2 had UID 304, and message 3 had UID in A003, we see that message 2 had UID 304, and message 3 had UID
319; therefore, UIDs 305 through 310 do not exist (refer to 319; therefore, UIDs 305 through 310 do not exist (refer to
Section 2.3.1.1 for further explanation). A006 is an example of a Section 2.3.1.1 for further explanation). A006 is an example of a
message being copied that did not return a COPYUID; and, as expected, message being copied that did not return a COPYUID; and, as expected,
A007 shows that the mail store containing that mailbox does not A007 shows that the mail store containing that mailbox does not
support persistent UIDs. support persistent UIDs.
Note: The APPEND command is not used for message delivery, because | Note: The APPEND command is not used for message delivery,
it does not provide a mechanism to transfer [SMTP] envelope | because it does not provide a mechanism to transfer [SMTP]
information. | envelope information.
6.3.13. IDLE Command 6.3.13. IDLE Command
Arguments: none Arguments: none
Responses: continuation data will be requested; the client sends the Responses: continuation data will be requested; the client sends
continuation data "DONE" to end the command the continuation data "DONE" to end the command
Result: OK - IDLE completed after client sent "DONE" Result: OK - IDLE completed after client sent "DONE"
NO - failure: the server will not allow the IDLE command NO - failure: the server will not allow the IDLE
at this time command at this time
BAD - command unknown or arguments invalid BAD - command unknown or arguments invalid
Without the IDLE command a client would need to poll the server for Without the IDLE command, a client would need to poll the server for
changes to the selected mailbox (new mail, deletions, flag changes). changes to the selected mailbox (new mail, deletions, and flag
It's often more desirable to have the server transmit updates to the changes). It's often more desirable to have the server transmit
client in real time. This allows a user to see new mail immediately. updates to the client in real time. This allows a user to see new
The IDLE command allows a client to tell the server that it's ready mail immediately. The IDLE command allows a client to tell the
to accept such real-time updates. server that it's ready to accept such real-time updates.
The IDLE command is sent from the client to the server when the The IDLE command is sent from the client to the server when the
client is ready to accept unsolicited update messages. The server client is ready to accept unsolicited update messages. The server
requests a response to the IDLE command using the continuation ("+") requests a response to the IDLE command using the continuation ("+")
response. The IDLE command remains active until the client responds response. The IDLE command remains active until the client responds
to the continuation, and as long as an IDLE command is active, the to the continuation, and as long as an IDLE command is active, the
server is now free to send untagged EXISTS, EXPUNGE, FETCH, and other server is now free to send untagged EXISTS, EXPUNGE, FETCH, and other
responses at any time. If the server chooses to send unsolicited responses at any time. If the server chooses to send unsolicited
FETCH responses, they MUST include UID FETCH item. FETCH responses, they MUST include a UID FETCH item.
The IDLE command is terminated by the receipt of a "DONE" The IDLE command is terminated by the receipt of a "DONE"
continuation from the client; such response satisfies the server's continuation from the client; such response satisfies the server's
continuation request. At that point, the server MAY send any continuation request. At that point, the server MAY send any
remaining queued untagged responses and then MUST immediately send remaining queued untagged responses and then MUST immediately send
the tagged response to the IDLE command and prepare to process other the tagged response to the IDLE command and prepare to process other
commands. As for other commands, the processing of any new command commands. As for other commands, the processing of any new command
may cause the sending of unsolicited untagged responses, subject to may cause the sending of unsolicited untagged responses, subject to
the ambiguity limitations. The client MUST NOT send a command while the ambiguity limitations. The client MUST NOT send a command while
the server is waiting for the DONE, since the server will not be able the server is waiting for the DONE, since the server will not be able
to distinguish a command from a continuation. to distinguish a command from a continuation.
The server MAY consider a client inactive if it has an IDLE command The server MAY consider a client inactive if it has an IDLE command
running, and if such a server has an inactivity timeout it MAY log running, and if such a server has an inactivity timeout, it MAY log
the client off implicitly at the end of its timeout period. Because the client off implicitly at the end of its timeout period. Because
of that, clients using IDLE are advised to terminate the IDLE and re- of that, clients using IDLE are advised to terminate IDLE and reissue
issue it at least every 29 minutes to avoid being logged off. This it at least every 29 minutes to avoid being logged off. This still
still allows a client to receive immediate mailbox updates even allows a client to receive immediate mailbox updates even though it
though it need only "poll" at half hour intervals. need only "poll" at half hour intervals.
Example: C: A001 SELECT INBOX Example:
S: * FLAGS (\Deleted \Seen \Flagged)
S: * OK [PERMANENTFLAGS (\Deleted \Seen \Flagged)] Limited C: A001 SELECT INBOX
S: * 3 EXISTS S: * FLAGS (\Deleted \Seen \Flagged)
S: * OK [UIDVALIDITY 1] S: * OK [PERMANENTFLAGS (\Deleted \Seen \Flagged)] Limited
S: * OK [UIDNEXT 1] S: * 3 EXISTS
S: * LIST () "/" INBOX S: * OK [UIDVALIDITY 1]
S: A001 OK [READ-WRITE] SELECT completed S: * OK [UIDNEXT 1]
C: A002 IDLE S: * LIST () "/" INBOX
S: + idling S: A001 OK [READ-WRITE] SELECT completed
...time passes; new mail arrives... C: A002 IDLE
S: * 4 EXISTS S: + idling
C: DONE ...time passes; new mail arrives...
S: A002 OK IDLE terminated S: * 4 EXISTS
...another client expunges message 2 now... C: DONE
C: A003 FETCH 4 ALL S: A002 OK IDLE terminated
S: * 4 FETCH (...) ...another client expunges message 2 now...
S: A003 OK FETCH completed C: A003 FETCH 4 ALL
C: A004 IDLE S: * 4 FETCH (...)
S: * 2 EXPUNGE S: A003 OK FETCH completed
S: * 3 EXISTS C: A004 IDLE
S: + idling S: * 2 EXPUNGE
...time passes; another client expunges message 3... S: * 3 EXISTS
S: * 3 EXPUNGE S: + idling
S: * 2 EXISTS ...time passes; another client expunges message 3...
...time passes; new mail arrives... S: * 3 EXPUNGE
S: * 3 EXISTS S: * 2 EXISTS
C: DONE ...time passes; new mail arrives...
S: A004 OK IDLE terminated S: * 3 EXISTS
C: A005 FETCH 3 ALL C: DONE
S: * 3 FETCH (...) S: A004 OK IDLE terminated
S: A005 OK FETCH completed C: A005 FETCH 3 ALL
C: A006 IDLE S: * 3 FETCH (...)
S: A005 OK FETCH completed
C: A006 IDLE
6.4. Client Commands - Selected State 6.4. Client Commands - Selected State
In the selected state, commands that manipulate messages in a mailbox In the selected state, commands that manipulate messages in a mailbox
are permitted. are permitted.
In addition to the universal commands (CAPABILITY, NOOP, and LOGOUT), In addition to the universal commands (CAPABILITY, NOOP, and LOGOUT),
and the authenticated state commands (SELECT, EXAMINE, NAMESPACE, and the authenticated state commands (SELECT, EXAMINE, NAMESPACE,
CREATE, DELETE, RENAME, SUBSCRIBE, UNSUBSCRIBE, LIST, STATUS, and CREATE, DELETE, RENAME, SUBSCRIBE, UNSUBSCRIBE, LIST, STATUS, and
APPEND), the following commands are valid in the selected state: APPEND), the following commands are valid in the selected state:
CLOSE, UNSELECT, EXPUNGE, SEARCH, FETCH, STORE, COPY, MOVE, and UID. CLOSE, UNSELECT, EXPUNGE, SEARCH, FETCH, STORE, COPY, MOVE, and UID.
6.4.1. CLOSE Command 6.4.1. CLOSE Command
Arguments: none Arguments: none
Responses: no specific responses for this command Responses: no specific responses for this command
Result: OK - close completed, now in authenticated state Result: OK - close completed, now in authenticated state
BAD - command unknown or arguments invalid BAD - command unknown or arguments invalid
The CLOSE command permanently removes all messages that have the The CLOSE command permanently removes all messages that have the
\Deleted flag set from the currently selected mailbox, and returns to \Deleted flag set from the currently selected mailbox, and it returns
the authenticated state from the selected state. No untagged EXPUNGE to the authenticated state from the selected state. No untagged
responses are sent. EXPUNGE responses are sent.
No messages are removed, and no error is given, if the mailbox is No messages are removed, and no error is given, if the mailbox is
selected by an EXAMINE command or is otherwise selected read-only. selected by an EXAMINE command or is otherwise selected as read-only.
Even if a mailbox is selected, a SELECT, EXAMINE, or LOGOUT command Even if a mailbox is selected, a SELECT, EXAMINE, or LOGOUT command
MAY be issued without previously issuing a CLOSE command. The MAY be issued without previously issuing a CLOSE command. The
SELECT, EXAMINE, and LOGOUT commands implicitly close the currently SELECT, EXAMINE, and LOGOUT commands implicitly close the currently
selected mailbox without doing an expunge. However, when many selected mailbox without doing an expunge. However, when many
messages are deleted, a CLOSE-LOGOUT or CLOSE-SELECT sequence is messages are deleted, a CLOSE-LOGOUT or CLOSE-SELECT sequence is
considerably faster than an EXPUNGE-LOGOUT or EXPUNGE-SELECT because considerably faster than an EXPUNGE-LOGOUT or EXPUNGE-SELECT because
no untagged EXPUNGE responses (which the client would probably no untagged EXPUNGE responses (which the client would probably
ignore) are sent. ignore) are sent.
Example: C: A341 CLOSE Example:
S: A341 OK CLOSE completed
C: A341 CLOSE
S: A341 OK CLOSE completed
6.4.2. UNSELECT Command 6.4.2. UNSELECT Command
Arguments: none Arguments: none
Responses: no specific responses for this command Responses: no specific responses for this command
Result: OK - unselect completed, now in authenticated state Result: OK - unselect completed, now in authenticated state
BAD - no mailbox selected, or argument supplied but none BAD - no mailbox selected, or argument supplied but
permitted none permitted
The UNSELECT command frees session's resources associated with the The UNSELECT command frees a session's resources associated with the
selected mailbox and returns the server to the authenticated state. selected mailbox and returns the server to the authenticated state.
This command performs the same actions as CLOSE, except that no This command performs the same actions as CLOSE, except that no
messages are permanently removed from the currently selected mailbox. messages are permanently removed from the currently selected mailbox.
Example: C: A342 UNSELECT Example:
S: A342 OK Unselect completed
C: A342 UNSELECT
S: A342 OK Unselect completed
6.4.3. EXPUNGE Command 6.4.3. EXPUNGE Command
Arguments: none Arguments: none
Responses: untagged responses: EXPUNGE Responses: untagged responses: EXPUNGE
Result: OK - expunge completed Result: OK - expunge completed
NO - expunge failure: can't expunge (e.g., permission NO - expunge failure: can't expunge (e.g., permission
denied) denied)
BAD - command unknown or arguments invalid BAD - command unknown or arguments invalid
The EXPUNGE command permanently removes all messages that have the The EXPUNGE command permanently removes all messages that have the
\Deleted flag set from the currently selected mailbox. Before \Deleted flag set from the currently selected mailbox. Before
returning an OK to the client, an untagged EXPUNGE response is sent returning an OK to the client, an untagged EXPUNGE response is sent
for each message that is removed. for each message that is removed.
Example: C: A202 EXPUNGE Example:
S: * 3 EXPUNGE
S: * 3 EXPUNGE C: A202 EXPUNGE
S: * 5 EXPUNGE S: * 3 EXPUNGE
S: * 8 EXPUNGE S: * 3 EXPUNGE
S: A202 OK EXPUNGE completed S: * 5 EXPUNGE
S: * 8 EXPUNGE
S: A202 OK EXPUNGE completed
Note: In this example, messages 3, 4, 7, and 11 had the \Deleted flag Note: In this example, messages 3, 4, 7, and 11 had the \Deleted flag
set. See the description of the EXPUNGE response (Section 7.5.1) for set. See the description of the EXPUNGE response (Section 7.5.1) for
further explanation. further explanation.
6.4.4. SEARCH Command 6.4.4. SEARCH Command
Arguments: OPTIONAL result specifier Arguments: OPTIONAL result specifier
OPTIONAL [CHARSET] specification
searching criteria (one or more)
Responses: OPTIONAL untagged response: ESEARCH OPTIONAL [CHARSET] specification
Result: OK - search completed searching criteria (one or more)
NO - search error: can't search that [CHARSET] or
criteria Responses: OPTIONAL untagged response: ESEARCH
BAD - command unknown or arguments invalid
Result: OK - search completed
NO - search error: can't search that [CHARSET] or
criteria
BAD - command unknown or arguments invalid
The SEARCH command searches the mailbox for messages that match the The SEARCH command searches the mailbox for messages that match the
given searching criteria. given searching criteria.
The SEARCH command may contain result options. Result options The SEARCH command may contain result options. Result options
control what kind of information is returned about messages matching control what kind of information is returned about messages matching
the search criteria in an untagged ESEARCH response. If no result the search criteria in an untagged ESEARCH response. If no result
option is specified or empty list of options is specified "()", ALL option is specified or empty list of options is specified as "()",
is assumed (see below). The order of individual options is ALL is assumed (see below). The order of individual options is
arbitrary. Individual options may contain parameters enclosed in arbitrary. Individual options may contain parameters enclosed in
parentheses. (However, if an option has a mandatory parameter, which parentheses. (However, if an option has a mandatory parameter, which
can always be represented as a number or a sequence-set, the option can always be represented as a number or a sequence-set, the option
parameter does not need the enclosing parentheses. See the Formal parameter does not need the enclosing parentheses. See "Formal
Syntax (Section 9) for more details). If an option has parameters, Syntax" (Section 9) for more details.) If an option has parameters,
they consist of atoms and/or strings and/or lists in a specific they consist of atoms and/or strings and/or lists in a specific
order. Any options not defined by extensions that the server order. Any options not defined by extensions that the server
supports MUST be rejected with a BAD response. supports MUST be rejected with a BAD response.
Note that IMAP4rev1 used SEARCH responses [RFC3501] instead of Note that IMAP4rev1 used SEARCH responses [RFC3501] instead of
ESEARCH responses. IMAP4rev2-only clients MUST ignore SEARCH ESEARCH responses. Clients that support only IMAP4rev2 MUST ignore
responses. SEARCH responses.
This document specifies the following result options: This document specifies the following result options:
MIN MIN
Return the lowest message number/UID that satisfies the SEARCH
criteria.
Return the lowest message number/UID that satisfies the SEARCH If the SEARCH results in no matches, the server MUST NOT include
criteria. the MIN result option in the ESEARCH response; however, it still
MUST send the ESEARCH response.
If the SEARCH results in no matches, the server MUST NOT
include the MIN result option in the ESEARCH response; however,
it still MUST send the ESEARCH response.
MAX MAX
Return the highest message number/UID that satisfies the SEARCH
criteria.
Return the highest message number/UID that satisfies the SEARCH If the SEARCH results in no matches, the server MUST NOT include
criteria. the MAX result option in the ESEARCH response; however, it still
MUST send the ESEARCH response.
If the SEARCH results in no matches, the server MUST NOT
include the MAX result option in the ESEARCH response; however,
it still MUST send the ESEARCH response.
ALL ALL
Return all message numbers/UIDs that satisfy the SEARCH criteria
using the sequence-set syntax. Note that the client MUST NOT
assume that messages/UIDs will be listed in any particular order.
Return all message numbers/UIDs that satisfy the SEARCH If the SEARCH results in no matches, the server MUST NOT include
criteria using the sequence-set syntax. Note, the client MUST the ALL result option in the ESEARCH response; however, it still
NOT assume that messages/UIDs will be listed in any particular MUST send the ESEARCH response.
order.
If the SEARCH results in no matches, the server MUST NOT
include the ALL result option in the ESEARCH response; however,
it still MUST send the ESEARCH response.
COUNT Return the number of messages that satisfy the SEARCH COUNT
criteria. This result option MUST always be included in the Return the number of messages that satisfy the SEARCH criteria.
ESEARCH response. This result option MUST always be included in the ESEARCH
response.
SAVE SAVE
This option tells the server to remember the result of the SEARCH
or UID SEARCH command (as well as any command based on SEARCH,
e.g., SORT and THREAD [RFC5256]) and store it in an internal
variable that we will reference as the "search result variable".
The client can use the "$" marker to reference the content of this
internal variable. The "$" marker can be used instead of message
sequence or UID sequence in order to indicate that the server
should substitute it with the list of messages from the search
result variable. Thus, the client can use the result of the
latest remembered SEARCH command as a parameter to another
command. See Section 6.4.4.1 for details on how the value of the
search result variable is determined, how it is affected by other
commands executed, and how the SAVE return option interacts with
other return options.
This option tells the server to remember the result of the In absence of any other SEARCH result option, the SAVE result
SEARCH or UID SEARCH command (as well as any command based on option also suppresses any ESEARCH response that would have been
SEARCH, e.g., SORT and THREAD [RFC5256]>) and store it in an otherwise returned by the SEARCH command.
internal variable that we will reference as the "search result
variable". The client can use the "$" marker to reference the
content of this internal variable. The "$" marker can be used
instead of message sequence or UID sequence in order to
indicate that the server should substitute it with the list of
messages from the search result variable. Thus, the client can
use the result of the latest remembered SEARCH command as a
parameter to another command. See Section 6.4.4.1 for details
on how the value of the search result variable is determined,
how it is affected by other commands executed, and how SAVE
return option interacts with other return options.
In absence of any other SEARCH result option, the SAVE result
option also suppresses any ESEARCH response that would have
been otherwise returned by the SEARCH command.
Note: future extensions to this document can allow servers to return Note: future extensions to this document can allow servers to return
multiple ESEARCH responses for a single extended SEARCH command. multiple ESEARCH responses for a single extended SEARCH command.
However all options specified above MUST result in a single ESEARCH However, all options specified above MUST result in a single ESEARCH
response if used by themselves or in combination. This guarantee response if used by themselves or in combination. This guarantee
simplifies processing in IMAP4rev2 clients. Future SEARCH extensions simplifies processing in IMAP4rev2 clients. Future SEARCH extensions
that relax this restriction will have to describe how results from that relax this restriction will have to describe how results from
multiple ESEARCH responses are to be combined. multiple ESEARCH responses are to be combined.
Searching criteria consist of one or more search keys. Searching criteria consist of one or more search keys.
When multiple keys are specified, the result is the intersection (AND When multiple keys are specified, the result is the intersection (AND
function) of all the messages that match those keys. For example, function) of all the messages that match those keys. For example,
the criteria DELETED FROM "SMITH" SINCE 1-Feb-1994 refers to all the criteria DELETED FROM "SMITH" SINCE 1-Feb-1994 refers to all
deleted messages from Smith with INTERNALDATE greater than February deleted messages from Smith with INTERNALDATE greater than February
1, 1994. A search key can also be a parenthesized list of one or 1, 1994. A search key can also be a parenthesized list of one or
more search keys (e.g., for use with the OR and NOT keys). more search keys (e.g., for use with the OR and NOT keys).
Server implementations MAY exclude [MIME-IMB] body parts with Server implementations MAY exclude [MIME-IMB] body parts with
terminal content media types other than TEXT and MESSAGE from terminal content media types other than TEXT and MESSAGE from
consideration in SEARCH matching. consideration in SEARCH matching.
The OPTIONAL [CHARSET] specification consists of the word "CHARSET" The OPTIONAL [CHARSET] specification consists of the word "CHARSET"
followed by a registered [CHARSET] [CHARSET-REG]. It indicates the followed by the name of a character set from the registry
[CHARSET-REG]. It indicates the [CHARSET] of the strings that appear
[CHARSET] of the strings that appear in the search criteria. in the search criteria. [MIME-IMB] content transfer encodings and
[MIME-IMB] content transfer encodings, and [MIME-HDRS] strings in [MIME-HDRS] strings in [RFC5322]/[MIME-IMB] headers MUST be decoded
[RFC-5322]/[MIME-IMB] headers, MUST be decoded before comparing text. before comparing text. Servers MUST support US-ASCII and UTF-8
Servers MUST support US-ASCII and UTF-8 charsets; other [CHARSET]s charsets; other CHARSETs MAY be supported. Clients SHOULD use UTF-8.
MAY be supported. Clients SHOULD use UTF-8. Note that if "CHARSET" Note that if CHARSET is not provided, IMAP4rev2 servers MUST assume
is not provided IMAP4rev2 servers MUST assume UTF-8, so selecting UTF-8, so selecting CHARSET UTF-8 is redundant. It is permitted for
CHARSET UTF-8 is redundant. It is permitted for improved improved compatibility with existing IMAP4rev1 clients.
compatibility with existing IMAP4rev1 clients.
If the server does not support the specified [CHARSET], it MUST If the server does not support the specified [CHARSET], it MUST
return a tagged NO response (not a BAD). This response SHOULD return a tagged NO response (not a BAD). This response SHOULD
contain the BADCHARSET response code, which MAY list the [CHARSET]s contain the BADCHARSET response code, which MAY list the CHARSETs
supported by the server. supported by the server.
In all search keys that use strings and unless specified otherwise, a In all search keys that use strings, and unless otherwise specified,
message matches the key if the string is a substring of the a message matches the key if the string is a substring of the
associated text. The matching SHOULD be case-insensitive for associated text. The matching SHOULD be case insensitive for
characters within ASCII range. Consider using [IMAP-I18N] for characters within the ASCII range. Consider using [IMAP-I18N] for
language-sensitive case-insensitive searching. Note that the empty language-sensitive, case-insensitive searching. Note that the empty
string is a substring; this is useful when doing a HEADER search in string is a substring; this is useful when performing a HEADER search
order to test for a header field presence in the message. in order to test for a header field presence in the message.
The defined search keys are as follows. Refer to the Formal Syntax The defined search keys are as follows. Refer to "Formal Syntax"
section for the precise syntactic definitions of the arguments. (Section 9) for the precise syntactic definitions of the arguments.
<sequence set> Messages with message sequence numbers corresponding <sequence set>
to the specified message sequence number set. Messages with message sequence numbers corresponding to the
specified message sequence number set.
ALL All messages in the mailbox; the default initial key for ANDing. ALL
All messages in the mailbox; the default initial key for ANDing.
ANSWERED Messages with the \Answered flag set. ANSWERED
Messages with the \Answered flag set.
BCC <string> Messages that contain the specified string in the BCC <string>
envelope structure's BCC field. Messages that contain the specified string in the envelope
structure's Blind Carbon Copy (BCC) field.
BEFORE <date> Messages whose internal date (disregarding time and BEFORE <date>
timezone) is earlier than the specified date. Messages whose internal date (disregarding time and timezone) is
earlier than the specified date.
BODY <string> Messages that contain the specified string in the body BODY <string>
of the message. Unlike TEXT (see below), this doesn't match any Messages that contain the specified string in the body of the
header fields. Servers are allowed to implement flexible matching message. Unlike TEXT (see below), this doesn't match any header
for this search key, for example matching "swim" to both "swam" fields. Servers are allowed to implement flexible matching for
and "swum" in English language text or only doing full word this search key, for example, by matching "swim" to both "swam"
and "swum" in English language text or only performing full word
matching (where "swim" will not match "swimming"). matching (where "swim" will not match "swimming").
CC <string> Messages that contain the specified string in the CC <string>
envelope structure's CC field. Messages that contain the specified string in the envelope
structure's CC field.
DELETED Messages with the \Deleted flag set.
DRAFT Messages with the \Draft flag set. DELETED
Messages with the \Deleted flag set.
FLAGGED Messages with the \Flagged flag set. DRAFT
Messages with the \Draft flag set.
FROM <string> Messages that contain the specified string in the FLAGGED
envelope structure's FROM field. Messages with the \Flagged flag set.
HEADER <field-name> <string> Messages that have a header field with FROM <string>
the specified field-name (as defined in [RFC-5322]) and that Messages that contain the specified string in the envelope
contains the specified string in the text of the header field structure's FROM field.
(what comes after the colon). If the string to search is zero-
length, this matches all messages that have a header field with
the specified field-name regardless of the contents. Servers
should use substring search for this SEARCH item, as clients can
use it for automatic processing not initiated by end users. For
example this can be used for searching for Message-ID or Content-
Type header field values that need to be exact, or for searches in
header fields that the IMAP server might not know anything about.
KEYWORD <flag> Messages with the specified keyword flag set. HEADER <field-name> <string>
Messages that have a header field with the specified field-name
(as defined in [RFC5322]) and that contain the specified string in
the text of the header field (what comes after the colon). If the
string to search is zero-length, this matches all messages that
have a header field with the specified field-name regardless of
the contents. Servers should use a substring search for this
SEARCH item, as clients can use it for automatic processing not
initiated by end users. For example, this can be used when
searching for Message-ID or Content-Type header field values that
need to be exact or for searches in header fields that the IMAP
server might not know anything about.
LARGER <n> Messages with an [RFC-5322] size larger than the KEYWORD <flag>
specified number of octets. Messages with the specified keyword flag set.
NOT <search-key> Messages that do not match the specified search LARGER <n>
key. Messages with an RFC822.SIZE larger than the specified number of
octets.
ON <date> Messages whose internal date (disregarding time and NOT <search-key>
timezone) is within the specified date. Messages that do not match the specified search key.
OR <search-key1> <search-key2> Messages that match either search ON <date>
key. Messages whose internal date (disregarding time and timezone) is
within the specified date.
SEEN Messages that have the \Seen flag set. OR <search-key1> <search-key2>
Messages that match either search key.
SENTBEFORE <date> Messages whose [RFC-5322] Date: header field SEEN
(disregarding time and timezone) is earlier than the specified Messages that have the \Seen flag set.
date.
SENTON <date> Messages whose [RFC-5322] Date: header field SENTBEFORE <date>
(disregarding time and timezone) is within the specified date. Messages whose [RFC5322] Date: header field (disregarding time and
timezone) is earlier than the specified date.
SENTSINCE <date> Messages whose [RFC-5322] Date: header field SENTON <date>
(disregarding time and timezone) is within or later than the Messages whose [RFC5322] Date: header field (disregarding time and
specified date. timezone) is within the specified date.
SINCE <date> Messages whose internal date (disregarding time and SENTSINCE <date>
Messages whose [RFC5322] Date: header field (disregarding time and
timezone) is within or later than the specified date. timezone) is within or later than the specified date.
SMALLER <n> Messages with an [RFC-5322] size smaller than the SINCE <date>
specified number of octets. Messages whose internal date (disregarding time and timezone) is
within or later than the specified date.
SUBJECT <string> Messages that contain the specified string in the SMALLER <n>
envelope structure's SUBJECT field. Messages with an RFC822.SIZE smaller than the specified number of
octets.
TEXT <string> Messages that contain the specified string in the SUBJECT <string>
header (including MIME header fields) or body of the message. Messages that contain the specified string in the envelope
Servers are allowed to implement flexible matching for this search structure's SUBJECT field.
key, for example matching "swim" to both "swam" and "swum" in
English language text or only doing full word matching (where
"swim" will not match "swimming").
TO <string> Messages that contain the specified string in the TEXT <string>
envelope structure's TO field. Messages that contain the specified string in the header
(including MIME header fields) or body of the message. Servers
are allowed to implement flexible matching for this search key,
for example, matching "swim" to both "swam" and "swum" in English
language text or only performing full-word matching (where "swim"
will not match "swimming").
UID <sequence set> Messages with unique identifiers corresponding to TO <string>
the specified unique identifier set. Sequence set ranges are Messages that contain the specified string in the envelope
permitted. structure's TO field.
UNANSWERED Messages that do not have the \Answered flag set. UID <sequence set>
Messages with unique identifiers corresponding to the specified
unique identifier set. Sequence-set ranges are permitted.
UNDELETED Messages that do not have the \Deleted flag set. UNANSWERED
Messages that do not have the \Answered flag set.
UNDRAFT Messages that do not have the \Draft flag set. UNDELETED
Messages that do not have the \Deleted flag set.
UNFLAGGED Messages that do not have the \Flagged flag set. UNDRAFT
Messages that do not have the \Draft flag set.
UNKEYWORD <flag> Messages that do not have the specified keyword UNFLAGGED
flag set. Messages that do not have the \Flagged flag set.
UNSEEN Messages that do not have the \Seen flag set. UNKEYWORD <flag>
Messages that do not have the specified keyword flag set.
Example: C: A282 SEARCH RETURN (MIN COUNT) FLAGGED UNSEEN
SINCE 1-Feb-1994 NOT FROM "Smith" Messages that do not have the \Seen flag set.
S: * ESEARCH (TAG "A282") MIN 2 COUNT 3
S: A282 OK SEARCH completed
Example: C: A283 SEARCH RETURN () FLAGGED Example:
SINCE 1-Feb-1994 NOT FROM "Smith"
S: * ESEARCH (TAG "A283") ALL 2,10:11
S: A283 OK SEARCH completed
Example: C: A284 SEARCH TEXT "string not in mailbox" C: A282 SEARCH RETURN (MIN COUNT) FLAGGED
S: * ESEARCH (TAG "A284") SINCE 1-Feb-1994 NOT FROM "Smith"
S: A284 OK SEARCH completed S: * ESEARCH (TAG "A282") MIN 2 COUNT 3
C: A285 SEARCH CHARSET UTF-8 TEXT {6} S: A282 OK SEARCH completed
S: + Ready for literal text
C: XXXXXX
S: * ESEARCH (TAG "A285") ALL 43
S: A285 OK SEARCH completed
Note: Since this document is restricted to 7-bit ASCII text, it is Example:
not possible to show actual UTF-8 data. The "XXXXXX" is a
placeholder for what would be 6 octets of 8-bit data in an actual C: A283 SEARCH RETURN () FLAGGED
transaction. SINCE 1-Feb-1994 NOT FROM "Smith"
S: * ESEARCH (TAG "A283") ALL 2,10:11
S: A283 OK SEARCH completed
Example:
C: A284 SEARCH TEXT "string not in mailbox"
S: * ESEARCH (TAG "A284")
S: A284 OK SEARCH completed
C: A285 SEARCH CHARSET UTF-8 TEXT {12}
S: + Ready for literal text
C: отпуск
S: * ESEARCH (TAG "A285") ALL 43
S: A285 OK SEARCH completed
The following example demonstrates finding the first unseen message The following example demonstrates finding the first unseen message
in the mailbox: in the mailbox:
Example: C: A284 SEARCH RETURN (MIN) UNSEEN Example:
S: * ESEARCH (TAG "A284") MIN 4
S: A284 OK SEARCH completed C: A284 SEARCH RETURN (MIN) UNSEEN
S: * ESEARCH (TAG "A284") MIN 4
S: A284 OK SEARCH completed
The following example demonstrates that if the ESEARCH UID indicator The following example demonstrates that if the ESEARCH UID indicator
is present, all data in the ESEARCH response is referring to UIDs; is present, all data in the ESEARCH response is referring to UIDs;
for example, the MIN result specifier will be followed by a UID. for example, the MIN result specifier will be followed by a UID.
Example: C: A285 UID SEARCH RETURN (MIN MAX) 1:5000 Example:
S: * ESEARCH (TAG "A285") UID MIN 7 MAX 3800
S: A285 OK SEARCH completed C: A285 UID SEARCH RETURN (MIN MAX) 1:5000
S: * ESEARCH (TAG "A285") UID MIN 7 MAX 3800
S: A285 OK SEARCH completed
The following example demonstrates returning the number of deleted The following example demonstrates returning the number of deleted
messages: messages:
Example: C: A286 SEARCH RETURN (COUNT) DELETED Example:
S: * ESEARCH (TAG "A286") COUNT 15
S: A286 OK SEARCH completed
6.4.4.1. SAVE result option and SEARCH result variable C: A286 SEARCH RETURN (COUNT) DELETED
S: * ESEARCH (TAG "A286") COUNT 15
S: A286 OK SEARCH completed
6.4.4.1. SAVE Result Option and SEARCH Result Variable
Upon successful completion of a SELECT or an EXAMINE command (after Upon successful completion of a SELECT or an EXAMINE command (after
the tagged OK response), the current search result variable is reset the tagged OK response), the current search result variable is reset
to the empty sequence. to the empty sequence.
A successful SEARCH command with the SAVE result option sets the A successful SEARCH command with the SAVE result option sets the
value of the search result variable to the list of messages found in value of the search result variable to the list of messages found in
the SEARCH command. For example, if no messages were found, the the SEARCH command. For example, if no messages were found, the
search result variable will contain the empty sequence. search result variable will contain the empty sequence.
Any of the following SEARCH commands MUST NOT change the search Any of the following SEARCH commands MUST NOT change the search
result variable: result variable:
a SEARCH command that caused the server to return the BAD tagged a SEARCH command that caused the server to return the BAD tagged
response, response,
a SEARCH command with no SAVE result option that caused the server a SEARCH command with no SAVE result option that caused the server
to return NO tagged response, to return NO tagged response, and
a successful SEARCH command with no SAVE result option. a successful SEARCH command with no SAVE result option.
A SEARCH command with the SAVE result option that caused the server A SEARCH command with the SAVE result option that caused the server
to return the NO tagged response sets the value of the search result to return the NO tagged response sets the value of the search result
variable to the empty sequence. variable to the empty sequence.
When a message listed in the search result variable is EXPUNGEd, it When a message listed in the search result variable is EXPUNGEd, it
is automatically removed from the list. Implementors are reminded is automatically removed from the list. Implementors are reminded
that if the server stores the list as a list of message numbers, it that if the server stores the list as a list of message numbers, it
MUST automatically adjust them when notifying the client about MUST automatically adjust them when notifying the client about
expunged messages, as described in Section 7.5.1. expunged messages, as described in Section 7.5.1.
If the server decides to send a new UIDVALIDITY value while the If the server decides to send a new UIDVALIDITY value while the
mailbox is opened, this causes resetting of the search variable to mailbox is opened, it causes the resetting of the search variable to
the empty sequence. the empty sequence.
Note that even if the "$" marker contains the empty sequence of Note that even if the "$" marker contains the empty sequence of
messages, it must be treated by all commands accepting message sets messages, it must be treated by all commands accepting message sets
as parameters as a valid, but non-matching list of messages. For as parameters as a valid, but non-matching, list of messages. For
example, the "FETCH $" command would return a tagged OK response and example, the "FETCH $" command would return a tagged OK response and
no FETCH responses. See also the Example 5 in Section 6.4.4.4. no FETCH responses. See also Example 5 in Section 6.4.4.4.
The SAVE result option doesn't change whether the server would return The SAVE result option doesn't change whether the server would return
items corresponding to MIN, MAX, ALL, or COUNT result options. items corresponding to MIN, MAX, ALL, or COUNT result options.
When the SAVE result option is combined with the MIN or MAX result When the SAVE result option is combined with the MIN or MAX result
option, and both ALL and COUNT result options are absent, the option, and both ALL and COUNT result options are absent, the
corresponding MIN/MAX is returned (if the search result is not corresponding MIN/MAX is returned (if the search result is not
empty), but the "$" marker would contain a single message as returned empty), but the "$" marker would contain a single message as returned
in the MIN/MAX return item. in the MIN/MAX return item.
If the SAVE result option is combined with both MIN and MAX result If the SAVE result option is combined with both MIN and MAX result
options, and both ALL and COUNT result options are absent, the "$" options, and both ALL and COUNT result options are absent, the "$"
marker would contain zero, one or two messages as returned in the marker would contain zero messages, one message, or two messages as
MIN/MAX return items. returned in the MIN/MAX return items.
If the SAVE result option is combined with the ALL and/or COUNT If the SAVE result option is combined with the ALL and/or COUNT
result option(s), the "$" marker would always contain all messages result option(s), the "$" marker would always contain all messages
found by the SEARCH or UID SEARCH command. found by the SEARCH or UID SEARCH command.
The following table summarizes the additional requirement on ESEARCH The following table summarizes the additional requirement on ESEARCH
server implementations described in this section. server implementations described in this section.
+------------------------------+--------------------+ +==============================+====================+
| Combination of Result option | "$" marker value | | Combination of Result Option | "$" Marker Value |
+------------------------------+--------------------+ +==============================+====================+
| SAVE MIN | MIN | | SAVE MIN | MIN |
+------------------------------+--------------------+
| SAVE MAX | MAX | | SAVE MAX | MAX |
+------------------------------+--------------------+
| SAVE MIN MAX | MIN & MAX | | SAVE MIN MAX | MIN & MAX |
+------------------------------+--------------------+
| SAVE * [m] | all found messages | | SAVE * [m] | all found messages |
+------------------------------+--------------------+ +------------------------------+--------------------+
Table 4
where '*' means "ALL" and/or "COUNT", and '[m]' means optional "MIN" where '*' means "ALL" and/or "COUNT", and '[m]' means optional "MIN"
and/or "MAX" and/or "MAX"
Implementation note: server implementors should note that "$" can Implementation note: server implementors should note that "$" can
reference IMAP message sequences or UID sequences, depending on the reference IMAP message sequences or UID sequences, depending on the
context where it is used. For example, the "$" marker can be set as context where it is used. For example, the "$" marker can be set as
a result of a SEARCH (SAVE) command and used as a parameter to a UID a result of a SEARCH (SAVE) command and used as a parameter to a UID
FETCH command (which accepts a UID sequence, not a message sequence), FETCH command (which accepts a UID sequence, not a message sequence),
or the "$" marker can be set as a result of a UID SEARCH (SAVE) or the "$" marker can be set as a result of a UID SEARCH (SAVE)
command and used as a parameter to a FETCH command (which accepts a command and used as a parameter to a FETCH command (which accepts a
message sequence, not a UID sequence). Server implementations need message sequence, not a UID sequence). Server implementations need
to automatically map the "$" marker value to message numbers or UIDs, to automatically map the "$" marker value to message numbers or UIDs,
depending on context where the "$" marker is used. depending on the context where the "$" marker is used.
6.4.4.2. Multiple Commands in Progress 6.4.4.2. Multiple Commands in Progress
Use of a SEARCH RETURN (SAVE) command followed by a command using the Use of a SEARCH RETURN (SAVE) command followed by a command using the
"$" marker creates direct dependency between the two commands. As "$" marker creates direct dependency between the two commands. As
directed by Section 5.5, a server MUST execute the two commands in directed by Section 5.5, a server MUST execute the two commands in
the order they were received. the order they were received.
A client MAY pipeline a SEARCH RETURN (SAVE) command with one or more A client MAY pipeline a SEARCH RETURN (SAVE) command with one or more
command using the "$" marker, as long as this doesn't create an commands using the "$" marker, as long as this doesn't create an
ambiguity, as described in Section 5.5. Examples 7-9 in ambiguity, as described in Section 5.5. Examples 7-9 in
Section 6.4.4.4 explain this in more details. Section 6.4.4.4 explain this in more details.
6.4.4.3. Refusing to Save Search Results 6.4.4.3. Refusing to Save Search Results
In some cases, the server MAY refuse to save a SEARCH (SAVE) result, In some cases, the server MAY refuse to save a SEARCH (SAVE) result,
for example, if an internal limit on the number of saved results is for example, if an internal limit on the number of saved results is
reached. In this case, the server MUST return a tagged NO response reached. In this case, the server MUST return a tagged NO response
containing the NOTSAVED response code and set the search result containing the NOTSAVED response code and set the search result
variable to the empty sequence, as described in Section 6.4.4.1. variable to the empty sequence, as described in Section 6.4.4.1.
6.4.4.4. Examples showing use of SAVE result option 6.4.4.4. Examples Showing Use of the SAVE Result Option
Only in this section: explanatory comments in examples that start Only in this section: explanatory comments in examples that start
with // are not part of the protocol. with // are not part of the protocol.
1) The following example demonstrates how the client can use the 1. The following example demonstrates how the client can use the
result of a SEARCH command to FETCH headers of interesting messages: result of a SEARCH command to FETCH headers of interesting
messages:
Example 1: Example 1:
C: A282 SEARCH RETURN (SAVE) FLAGGED SINCE 1-Feb-1994
NOT FROM "Smith"
S: A282 OK SEARCH completed, result saved
C: A283 FETCH $ (UID INTERNALDATE FLAGS BODY.PEEK[HEADER])
S: * 2 FETCH (UID 14 ...
S: * 84 FETCH (UID 100 ...
S: * 882 FETCH (UID 1115 ...
S: A283 OK completed
The client can also pipeline the two commands: C: A282 SEARCH RETURN (SAVE) FLAGGED SINCE 1-Feb-1994
NOT FROM "Smith"
S: A282 OK SEARCH completed, result saved
C: A283 FETCH $ (UID INTERNALDATE FLAGS BODY.PEEK[HEADER])
S: * 2 FETCH (UID 14 ...
S: * 84 FETCH (UID 100 ...
S: * 882 FETCH (UID 1115 ...
S: A283 OK completed
Example 2: The client can also pipeline the two commands:
C: A282 SEARCH RETURN (SAVE) FLAGGED SINCE 1-Feb-1994
NOT FROM "Smith"
C: A283 FETCH $ (UID INTERNALDATE FLAGS BODY.PEEK[HEADER])
S: A282 OK SEARCH completed
S: * 2 FETCH (UID 14 ...
S: * 84 FETCH (UID 100 ...
S: * 882 FETCH (UID 1115 ...
S: A283 OK completed
2) The following example demonstrates that the result of one SEARCH Example 2:
command can be used as input to another SEARCH command:
Example 3: C: A282 SEARCH RETURN (SAVE) FLAGGED SINCE 1-Feb-1994
C: A300 SEARCH RETURN (SAVE) SINCE 1-Jan-2004 NOT FROM "Smith"
NOT FROM "Smith" C: A283 FETCH $ (UID INTERNALDATE FLAGS BODY.PEEK[HEADER])
S: A300 OK SEARCH completed S: A282 OK SEARCH completed
C: A301 UID SEARCH UID $ SMALLER 4096 S: * 2 FETCH (UID 14 ...
S: * ESEARCH (TAG "A301") UID ALL 17,900,901 S: * 84 FETCH (UID 100 ...
S: A301 OK completed S: * 882 FETCH (UID 1115 ...
S: A283 OK completed
Note that the second command in Example 3 can be replaced with: 2. The following example demonstrates that the result of one SEARCH
C: A301 UID SEARCH $ SMALLER 4096 command can be used as input to another SEARCH command:
and the result of the command would be the same.
3) The following example shows that the "$" marker can be combined Example 3:
with other message numbers using the OR SEARCH criterion.
Example 4: C: A300 SEARCH RETURN (SAVE) SINCE 1-Jan-2004
C: P282 SEARCH RETURN (SAVE) SINCE 1-Feb-1994 NOT FROM "Smith"
NOT FROM "Smith" S: A300 OK SEARCH completed
S: P282 OK SEARCH completed C: A301 UID SEARCH UID $ SMALLER 4096
C: P283 SEARCH CHARSET UTF-8 (OR $ 1,3000:3021) TEXT {8+} S: * ESEARCH (TAG "A301") UID ALL 17,900,901
C: YYYYYYYY S: A301 OK completed
S: * ESEARCH (TAG "P283") ALL 882,1102,3003,3005:3006
S: P283 OK completed
Note: Since this document format is restricted to 7-bit ASCII text, Note that the second command in Example 3 can be replaced with:
it is not possible to show actual UTF-8 data. The "YYYYYYYY" is a
placeholder for what would be 8 octets of 8-bit data in an actual
transaction.
4) The following example demonstrates that a failed SEARCH sets the C: A301 UID SEARCH $ SMALLER 4096
search result variable to the empty list. The server doesn't
implement the KOI8-R charset.
Example 5: and the result of the command would be the same.
C: B282 SEARCH RETURN (SAVE) SINCE 1-Feb-1994
NOT FROM "Smith"
S: B282 OK SEARCH completed
C: B283 SEARCH RETURN (SAVE) CHARSET KOI8-R
(OR $ 1,3000:3021) TEXT {4}
C: XXXX
S: B283 NO [BADCHARSET UTF-8] KOI8-R is not supported
//After this command the saved result variable contains
//no messages. A client that wants to reissue the B283
//SEARCH command with another CHARSET would have to reissue
//the B282 command as well. One possible workaround for
//this is to include the desired CHARSET parameter
//in the earliest SEARCH RETURN (SAVE) command in a
//sequence of related SEARCH commands, to cause
//the earliest SEARCH in the sequence to fail.
//A better approach might be to always use CHARSET UTF-8
//instead.
Note: Since this document format is restricted to 7-bit ASCII text, 3. The following example shows that the "$" marker can be combined
it is not possible to show actual KOI8-R data. The "XXXX" is a with other message numbers using the OR SEARCH criterion.
placeholder for what would be 4 octets of 8-bit data in an actual
transaction.
5) The following example demonstrates that it is not an error to use Example 4:
the "$" marker when it contains no messages.
Example 6: C: P282 SEARCH RETURN (SAVE) SINCE 1-Feb-1994
C: E282 SEARCH RETURN (SAVE) SINCE 28-Oct-2006 NOT FROM "Smith"
NOT FROM "Eric" S: P282 OK SEARCH completed
C: E283 COPY $ "Other Messages" C: P283 SEARCH CHARSET UTF-8 (OR $ 1,3000:3021) TEXT {8+}
//The "$" contains no messages C: мать
S: E282 OK SEARCH completed S: * ESEARCH (TAG "P283") ALL 882,1102,3003,3005:3006
S: E283 OK COPY completed, nothing copied S: P283 OK completed
Example 7: 4. The following example demonstrates that a failed SEARCH sets the
C: F282 SEARCH RETURN (SAVE) KEYWORD $Junk search result variable to the empty list. The server doesn't
C: F283 COPY $ "Junk" implement the KOI8-R charset.
C: F284 STORE $ +FLAGS.Silent (\Deleted)
S: F282 OK SEARCH completed
S: F283 OK COPY completed
S: F284 OK STORE completed
Example 8: Example 5:
C: G282 SEARCH RETURN (SAVE) KEYWORD $Junk
C: G283 SEARCH RETURN (ALL) SINCE 28-Oct-2006
FROM "Eric"
// The server can execute the two SEARCH commands
// in any order, as they don't have any dependency.
// For example, it may return:
S: * ESEARCH (TAG "G283") ALL 3:15,27,29:103
S: G283 OK SEARCH completed
S: G282 OK SEARCH completed
The following example demonstrates that the result of the second C: B282 SEARCH RETURN (SAVE) SINCE 1-Feb-1994
SEARCH RETURN (SAVE) always overrides the result of the first. NOT FROM "Smith"
S: B282 OK SEARCH completed
C: B283 SEARCH RETURN (SAVE) CHARSET KOI8-R
(OR $ 1,3000:3021) TEXT {4}
C: XXXX
S: B283 NO [BADCHARSET UTF-8] KOI8-R is not supported
//After this command, the saved result variable contains
//no messages. A client that wants to reissue the B283
//SEARCH command with another CHARSET would have to reissue
//the B282 command as well. One possible workaround for
//this is to include the desired CHARSET parameter
//in the earliest SEARCH RETURN (SAVE) command in a
//sequence of related SEARCH commands, to cause
//the earliest SEARCH in the sequence to fail.
//A better approach might be to always use CHARSET UTF-8
//instead.
Example 9: Note: Since this document format is restricted to 7-bit ASCII
C: H282 SEARCH RETURN (SAVE) KEYWORD $Junk text, it is not possible to show actual KOI8-R data. The "XXXX"
C: H283 SEARCH RETURN (SAVE) SINCE 28-Oct-2006 is a placeholder for what would be 4 octets of 8-bit data in an
FROM "Eric" actual transaction.
S: H282 OK SEARCH completed
S: H283 OK SEARCH completed
// At this point "$" would contain results of H283
The following example demonstrates behavioral difference for 5. The following example demonstrates that it is not an error to use
different combinations of ESEARCH result options. the "$" marker when it contains no messages.
Example 10: Example 6:
C: C282 SEARCH RETURN (ALL) SINCE 12-Feb-2006
NOT FROM "Smith"
S: * ESEARCH (TAG "C283") ALL 2,10:15,21
//$ value hasn't changed
S: C282 OK SEARCH completed
C: C283 SEARCH RETURN (ALL SAVE) SINCE 12-Feb-2006 C: E282 SEARCH RETURN (SAVE) SINCE 28-Oct-2006
NOT FROM "Smith" NOT FROM "Eric"
S: * ESEARCH (TAG "C283") ALL 2,10:15,21 C: E283 COPY $ "Other Messages"
//$ value is 2,10:15,21 //The "$" contains no messages
S: C283 OK SEARCH completed S: E282 OK SEARCH completed
S: E283 OK COPY completed, nothing copied
C: C284 SEARCH RETURN (SAVE MIN) SINCE 12-Feb-2006 Example 7:
NOT FROM "Smith"
S: * ESEARCH (TAG "C284") MIN 2
//$ value is 2
S: C284 OK SEARCH completed
C: C285 SEARCH RETURN (MAX SAVE MIN) SINCE C: F282 SEARCH RETURN (SAVE) KEYWORD $Junk
12-Feb-2006 NOT FROM "Smith" C: F283 COPY $ "Junk"
S: * ESEARCH (TAG "C285") MIN 2 MAX 21 C: F284 STORE $ +FLAGS.Silent (\Deleted)
//$ value is 2,21 S: F282 OK SEARCH completed
S: C285 OK SEARCH completed S: F283 OK COPY completed
S: F284 OK STORE completed
C: C286 SEARCH RETURN (MAX SAVE MIN COUNT) Example 8:
SINCE 12-Feb-2006 NOT FROM "Smith"
S: * ESEARCH (TAG "C286") MIN 2 MAX 21 COUNT 8
//$ value is 2,10:15,21
S: C286 OK SEARCH completed
C: C286 SEARCH RETURN (ALL SAVE MIN) SINCE C: G282 SEARCH RETURN (SAVE) KEYWORD $Junk
12-Feb-2006 NOT FROM "Smith" C: G283 SEARCH RETURN (ALL) SINCE 28-Oct-2006
S: * ESEARCH (TAG "C286") MIN 2 ALL 2,10:15,21 FROM "Eric"
//$ value is 2,10:15,21 // The server can execute the two SEARCH commands
S: C286 OK SEARCH completed // in any order, as they don't have any dependency.
// For example, it may return:
S: * ESEARCH (TAG "G283") ALL 3:15,27,29:103
S: G283 OK SEARCH completed
S: G282 OK SEARCH completed
The following example demonstrates that the result of the second
SEARCH RETURN (SAVE) always overrides the result of the first.
Example 9:
C: H282 SEARCH RETURN (SAVE) KEYWORD $Junk
C: H283 SEARCH RETURN (SAVE) SINCE 28-Oct-2006
FROM "Eric"
S: H282 OK SEARCH completed
S: H283 OK SEARCH completed
// At this point "$" would contain results of H283
The following example demonstrates behavioral difference for
different combinations of ESEARCH result options.
Example 10:
C: C282 SEARCH RETURN (ALL) SINCE 12-Feb-2006
NOT FROM "Smith"
S: * ESEARCH (TAG "C283") ALL 2,10:15,21
//$ value hasn't changed
S: C282 OK SEARCH completed
C: C283 SEARCH RETURN (ALL SAVE) SINCE 12-Feb-2006
NOT FROM "Smith"
S: * ESEARCH (TAG "C283") ALL 2,10:15,21
//$ value is 2,10:15,21
S: C283 OK SEARCH completed
C: C284 SEARCH RETURN (SAVE MIN) SINCE 12-Feb-2006
NOT FROM "Smith"
S: * ESEARCH (TAG "C284") MIN 2
//$ value is 2
S: C284 OK SEARCH completed
C: C285 SEARCH RETURN (MAX SAVE MIN) SINCE
12-Feb-2006 NOT FROM "Smith"
S: * ESEARCH (TAG "C285") MIN 2 MAX 21
//$ value is 2,21
S: C285 OK SEARCH completed
C: C286 SEARCH RETURN (MAX SAVE MIN COUNT)
SINCE 12-Feb-2006 NOT FROM "Smith"
S: * ESEARCH (TAG "C286") MIN 2 MAX 21 COUNT 8
//$ value is 2,10:15,21
S: C286 OK SEARCH completed
C: C286 SEARCH RETURN (ALL SAVE MIN) SINCE
12-Feb-2006 NOT FROM "Smith"
S: * ESEARCH (TAG "C286") MIN 2 ALL 2,10:15,21
//$ value is 2,10:15,21
S: C286 OK SEARCH completed
6.4.5. FETCH Command 6.4.5. FETCH Command
Arguments: sequence set Arguments: sequence set
message data item names or macro
Responses: untagged responses: FETCH message data item names or macro
Result: OK - fetch completed Responses: untagged responses: FETCH
NO - fetch error: can't fetch that data
BAD - command unknown or arguments invalid Result: OK - fetch completed
NO - fetch error: can't fetch that data
BAD - command unknown or arguments invalid
The FETCH command retrieves data associated with a message in the The FETCH command retrieves data associated with a message in the
mailbox. The data items to be fetched can be either a single atom or mailbox. The data items to be fetched can be either a single atom or
a parenthesized list. a parenthesized list.
Most data items, identified in the formal syntax (Section 9) under Most data items, identified in the formal syntax (Section 9) under
the msg-att-static rule, are static and MUST NOT change for any the msg-att-static rule, are static and MUST NOT change for any
particular message. Other data items, identified in the formal particular message. Other data items, identified in the formal
syntax under the msg-att-dynamic rule, MAY change, either as a result syntax under the msg-att-dynamic rule, MAY change either as a result
of a STORE command or due to external events. of a STORE command or due to external events.
For example, if a client receives an ENVELOPE for a message when For example, if a client receives an ENVELOPE for a message when
it already knows the envelope, it can safely ignore the newly it already knows the envelope, it can safely ignore the newly
transmitted envelope. transmitted envelope.
There are three macros which specify commonly-used sets of data There are three macros that specify commonly used sets of data items
items, and can be used instead of data items. A macro must be used and can be used instead of data items. A macro must be used by
by itself, and not in conjunction with other macros or data items. itself and not in conjunction with other macros or data items.
ALL Macro equivalent to: (FLAGS INTERNALDATE RFC822.SIZE ENVELOPE) ALL
Macro equivalent to: (FLAGS INTERNALDATE RFC822.SIZE ENVELOPE)
FAST Macro equivalent to: (FLAGS INTERNALDATE RFC822.SIZE) FAST
Macro equivalent to: (FLAGS INTERNALDATE RFC822.SIZE)
FULL Macro equivalent to: (FLAGS INTERNALDATE RFC822.SIZE ENVELOPE FULL
Macro equivalent to: (FLAGS INTERNALDATE RFC822.SIZE ENVELOPE
BODY) BODY)
Several data items reference "section" or "section-binary". See Several data items reference "section" or "section-binary". See
Section 6.4.5.1 for their detailed definition. Section 6.4.5.1 for their detailed definition.
The currently defined data items that can be fetched are: The currently defined data items that can be fetched are:
BINARY[<section-binary>]<<partial>> BINARY[<section-binary>]<<partial>>
Requests that the specified section be transmitted after
performing decoding of the section's Content-Transfer-Encoding.
Requests that the specified section be transmitted after The <partial> argument, if present, requests that a subset of the
performing Content-Transfer-Encoding-related decoding. data be returned. The semantics of a partial FETCH BINARY command
are the same as for a partial FETCH BODY command, with the
The <partial> argument, if present, requests that a subset of exception that the <partial> arguments refer to the DECODED
the data be returned. The semantics of a partial FETCH BINARY section data.
command are the same as for a partial FETCH BODY command, with
the exception that the <partial> arguments refer to the DECODED
section data.
Note that this data item can only be requested for leaf (i.e. Note that this data item can only be requested for leaf body
non multipart/*, non message/rfc822 and non message/global) parts: those that have media types other than multipart/*,
body parts. message/rfc822, or message/global.
BINARY.PEEK[<section-binary>]<<partial>> An alternate form of BINARY.PEEK[<section-binary>]<<partial>>
BINARY[<section-binary>] that does not implicitly set the \Seen An alternate form of BINARY[<section-binary>] that does not
flag. implicitly set the \Seen flag.
BINARY.SIZE[<section-binary>] BINARY.SIZE[<section-binary>]
Requests the decoded size of the section (i.e., the size to expect
in response to the corresponding FETCH BINARY request).
Requests the decoded size of the section (i.e., the size to Note: client authors are cautioned that this might be an expensive
expect in response to the corresponding FETCH BINARY request). operation for some server implementations. Needlessly issuing
this request could result in degraded performance due to servers
Note: client authors are cautioned that this might be an having to calculate the value every time the request is issued.
expensive operation for some server implementations.
Needlessly issuing this request could result in degraded
performance due to servers having to calculate the value every
time the request is issued.
Note that this data item can only be requested for leaf (i.e. Note that this data item can only be requested for leaf body
non multipart/*, non message/rfc822 and non message/global) parts: those that have media types other than multipart/*,
body parts. message/rfc822, or message/global.
BODY Non-extensible form of BODYSTRUCTURE. BODY
Non-extensible form of BODYSTRUCTURE.
BODY[<section>]<<partial>> BODY[<section>]<<partial>>
The text of a particular body section. If BODY[] is specified
(the section specification is omitted), the FETCH is requesting
the [RFC5322] expression of the entire message.
The text of a particular body section. It is possible to fetch a substring of the designated text. This
is done by appending an open angle bracket ("<"), the octet
position of the first desired octet, a period, the maximum number
of octets desired, and a close angle bracket (">") to the part
specifier. If the starting octet is beyond the end of the text,
an empty string is returned.
It is possible to fetch a substring of the designated text. Any partial fetch that attempts to read beyond the end of the text
This is done by appending an open angle bracket ("<"), the is truncated as appropriate. A partial fetch that starts at octet
octet position of the first desired octet, a period, the 0 is returned as a partial fetch, even if this truncation
maximum number of octets desired, and a close angle bracket happened.
(">") to the part specifier. If the starting octet is beyond
the end of the text, an empty string is returned.
Any partial fetch that attempts to read beyond the end of the Note: This means that BODY[]<0.2048> of a 1500-octet message
text is truncated as appropriate. A partial fetch that starts will return BODY[]<0> with a literal of size 1500, not BODY[].
at octet 0 is returned as a partial fetch, even if this
truncation happened.
Note: This means that BODY[]<0.2048> of a 1500-octet message Note: A substring fetch of a HEADER.FIELDS or HEADER.FIELDS.NOT
will return BODY[]<0> with a literal of size 1500, not part specifier is calculated after subsetting the header.
BODY[].
Note: A substring fetch of a HEADER.FIELDS or The \Seen flag is implicitly set; if this causes the flags to
HEADER.FIELDS.NOT part specifier is calculated after change, they SHOULD be included as part of the FETCH responses.
subsetting the header.
The \Seen flag is implicitly set; if this causes the flags to BODY.PEEK[<section>]<<partial>>
change, they SHOULD be included as part of the FETCH responses. An alternate form of BODY[<section>] that does not implicitly set
the \Seen flag.
BODY.PEEK[<section>]<<partial>> An alternate form of BODY[<section>] BODYSTRUCTURE
that does not implicitly set the \Seen flag. The [MIME-IMB] body structure of the message. This is computed by
the server by parsing the [MIME-IMB] header fields in the
[RFC5322] header and [MIME-IMB] headers. See Section 7.5.2 for
more details.
BODYSTRUCTURE The [MIME-IMB] body structure of the message. This is ENVELOPE
computed by the server by parsing the [MIME-IMB] header fields in The envelope structure of the message. This is computed by the
the [RFC-5322] header and [MIME-IMB] headers. See Section 7.5.2 server by parsing the [RFC5322] header into the component parts,
for more details. defaulting various fields as necessary. See Section 7.5.2 for
more details.
ENVELOPE The envelope structure of the message. This is computed by FLAGS
the server by parsing the [RFC-5322] header into the component The flags that are set for this message.
parts, defaulting various fields as necessary. See Section 7.5.2
for more details.
FLAGS The flags that are set for this message. INTERNALDATE
The internal date of the message.
INTERNALDATE The internal date of the message. RFC822.SIZE
The size of the message, as defined in Section 2.3.4.
RFC822.SIZE The [RFC-5322] size of the message. UID
The unique identifier for the message.
UID The unique identifier for the message. Example:
Example: C: A654 FETCH 2:4 (FLAGS BODY[HEADER.FIELDS (DATE FROM)]) C: A654 FETCH 2:4 (FLAGS BODY[HEADER.FIELDS (DATE FROM)])
S: * 2 FETCH .... S: * 2 FETCH ....
S: * 3 FETCH .... S: * 3 FETCH ....
S: * 4 FETCH .... S: * 4 FETCH ....
S: A654 OK FETCH completed S: A654 OK FETCH completed
6.4.5.1. FETCH section specification 6.4.5.1. FETCH Section Specification
Several FETCH data items reference "section" or "section-binary". Several FETCH data items reference "section" or "section-binary".
The section specification is a set of zero or more part specifiers The section specification is a set of zero or more part specifiers
delimited by periods. A part specifier is either a part number or delimited by periods. A part specifier is either a part number or
one of the following: HEADER, HEADER.FIELDS, HEADER.FIELDS.NOT, MIME, one of the following: HEADER, HEADER.FIELDS, HEADER.FIELDS.NOT, MIME,
and TEXT. (Non numeric part specifiers have to be the last specifier and TEXT. (Non-numeric part specifiers have to be the last specifier
in a section specification.) An empty section specification refers in a section specification.) An empty section specification refers
to the entire message, including the header. to the entire message, including the header.
Every message has at least one part number. Non-[MIME-IMB] messages, Every message has at least one part number. Messages that do not use
and non-multipart [MIME-IMB] messages with no encapsulated message, MIME, and MIME messages that are not multipart and have no
only have a part 1. encapsulated message within them, only have a part 1.
Multipart messages are assigned consecutive part numbers, as they Multipart messages are assigned consecutive part numbers, as they
occur in the message. If a particular part is of type message or occur in the message. If a particular part is of type message or
multipart, its parts MUST be indicated by a period followed by the multipart, its parts MUST be indicated by a period followed by the
part number within that nested multipart part. part number within that nested multipart part.
A part of type MESSAGE/RFC822 or MESSAGE/GLOBAL also has nested part A part of type MESSAGE/RFC822 or MESSAGE/GLOBAL also has nested part
numbers, referring to parts of the MESSAGE part's body. numbers, referring to parts of the MESSAGE part's body.
The HEADER, HEADER.FIELDS, HEADER.FIELDS.NOT, and TEXT part The HEADER, HEADER.FIELDS, HEADER.FIELDS.NOT, and TEXT part
specifiers can be the sole part specifier or can be prefixed by one specifiers can be the sole part specifier or can be prefixed by one
or more numeric part specifiers, provided that the numeric part or more numeric part specifiers, provided that the numeric part
specifier refers to a part of type MESSAGE/RFC822 or MESSAGE/GLOBAL. specifier refers to a part of type MESSAGE/RFC822 or MESSAGE/GLOBAL.
The MIME part specifier MUST be prefixed by one or more numeric part The MIME part specifier MUST be prefixed by one or more numeric part
specifiers. specifiers.
The HEADER, HEADER.FIELDS, and HEADER.FIELDS.NOT part specifiers The HEADER, HEADER.FIELDS, and HEADER.FIELDS.NOT part specifiers
refer to the [RFC-5322] header of the message or of an encapsulated refer to the [RFC5322] header of the message or of an encapsulated
[MIME-IMT] MESSAGE/RFC822 or MESSAGE/GLOBAL message. HEADER.FIELDS [MIME-IMT] MESSAGE/RFC822 or MESSAGE/GLOBAL message. HEADER.FIELDS
and HEADER.FIELDS.NOT are followed by a list of field-name (as and HEADER.FIELDS.NOT are followed by a list of field-names (as
defined in [RFC-5322]) names, and return a subset of the header. The defined in [RFC5322]) and return a subset of the header. The subset
subset returned by HEADER.FIELDS contains only those header fields returned by HEADER.FIELDS contains only those header fields with a
with a field-name that matches one of the names in the list; field-name that matches one of the names in the list; similarly, the
similarly, the subset returned by HEADER.FIELDS.NOT contains only the subset returned by HEADER.FIELDS.NOT contains only the header fields
header fields with a non-matching field-name. The field-matching is with a non-matching field-name. The field-matching is ASCII-range
ASCII range case-insensitive but otherwise exact. Subsetting does case insensitive but is otherwise exact. Subsetting does not exclude
not exclude the [RFC-5322] delimiting blank line between the header the [RFC5322] delimiting blank line between the header and the body;
and the body; the blank line is included in all header fetches, the blank line is included in all header fetches, except in the case
except in the case of a message which has no body and no blank line. of a message that has no body and no blank line.
The MIME part specifier refers to the [MIME-IMB] header for this The MIME part specifier refers to the [MIME-IMB] header for this
part. part.
The TEXT part specifier refers to the text body of the message, The TEXT part specifier refers to the text body of the message,
omitting the [RFC-5322] header. omitting the [RFC5322] header.
Here is an example of a complex message with some of its part Here is an example of a complex message with some of its part
specifiers: specifiers:
HEADER ([RFC-5322] header of the message) HEADER ([RFC5322] header of the message)
TEXT ([RFC-5322] text body of the message) MULTIPART/MIXED TEXT ([RFC5322] text body of the message) MULTIPART/MIXED
1 TEXT/PLAIN 1 TEXT/PLAIN
2 APPLICATION/OCTET-STREAM 2 APPLICATION/OCTET-STREAM
3 MESSAGE/RFC822 3 MESSAGE/RFC822
3.HEADER ([RFC-5322] header of the message) 3.HEADER ([RFC5322] header of the message)
3.TEXT ([RFC-5322] text body of the message) MULTIPART/MIXED 3.TEXT ([RFC5322] text body of the message) MULTIPART/MIXED
3.1 TEXT/PLAIN 3.1 TEXT/PLAIN
3.2 APPLICATION/OCTET-STREAM 3.2 APPLICATION/OCTET-STREAM
4 MULTIPART/MIXED 4 MULTIPART/MIXED
4.1 IMAGE/GIF 4.1 IMAGE/GIF
4.1.MIME ([MIME-IMB] header for the IMAGE/GIF) 4.1.MIME ([MIME-IMB] header for the IMAGE/GIF)
4.2 MESSAGE/RFC822 4.2 MESSAGE/RFC822
4.2.HEADER ([RFC-5322] header of the message) 4.2.HEADER ([RFC5322] header of the message)
4.2.TEXT ([RFC-5322] text body of the message) MULTIPART/MIXED 4.2.TEXT ([RFC5322] text body of the message) MULTIPART/MIXED
4.2.1 TEXT/PLAIN 4.2.1 TEXT/PLAIN
4.2.2 MULTIPART/ALTERNATIVE 4.2.2 MULTIPART/ALTERNATIVE
4.2.2.1 TEXT/PLAIN 4.2.2.1 TEXT/PLAIN
4.2.2.2 TEXT/RICHTEXT 4.2.2.2 TEXT/RICHTEXT
6.4.6. STORE Command 6.4.6. STORE Command
Arguments: sequence set Arguments: sequence set
message data item name
value for message data item
Responses: untagged responses: FETCH message data item name
Result: OK - store completed value for message data item
NO - store error: can't store that data
BAD - command unknown or arguments invalid Responses: untagged responses: FETCH
Result: OK - store completed
NO - store error: can't store that data
BAD - command unknown or arguments invalid
The STORE command alters data associated with a message in the The STORE command alters data associated with a message in the
mailbox. Normally, STORE will return the updated value of the data mailbox. Normally, STORE will return the updated value of the data
with an untagged FETCH response. A suffix of ".SILENT" in the data with an untagged FETCH response. A suffix of ".SILENT" in the data
item name prevents the untagged FETCH, and the server SHOULD assume item name prevents the untagged FETCH, and the server SHOULD assume
that the client has determined the updated value itself or does not that the client has determined the updated value itself or does not
care about the updated value. care about the updated value.
Note: Regardless of whether or not the ".SILENT" suffix was used, Note: Regardless of whether or not the ".SILENT" suffix was used,
the server SHOULD send an untagged FETCH response if a change to a the server SHOULD send an untagged FETCH response if a change to a
message's flags from an external source is observed. The intent message's flags from an external source is observed. The intent
is that the status of the flags is determinate without a race is that the status of the flags is determinate without a race
condition. condition.
The currently defined data items that can be stored are: The currently defined data items that can be stored are:
FLAGS <flag list> Replace the flags for the message with the FLAGS <flag list>
argument. The new value of the flags is returned as if a FETCH of Replace the flags for the message with the argument. The new
those flags was done. value of the flags is returned as if a FETCH of those flags was
done.
FLAGS.SILENT <flag list> Equivalent to FLAGS, but without returning FLAGS.SILENT <flag list>
a new value. Equivalent to FLAGS, but without returning a new value.
+FLAGS <flag list> Add the argument to the flags for the message. +FLAGS <flag list>
The new value of the flags is returned as if a FETCH of those Add the argument to the flags for the message. The new value of
flags was done. the flags is returned as if a FETCH of those flags was done.
+FLAGS.SILENT <flag list> Equivalent to +FLAGS, but without +FLAGS.SILENT <flag list>
returning a new value. Equivalent to +FLAGS, but without returning a new value.
-FLAGS <flag list> Remove the argument from the flags for the -FLAGS <flag list>
message. The new value of the flags is returned as if a FETCH of Remove the argument from the flags for the message. The new value
those flags was done. of the flags is returned as if a FETCH of those flags was done.
-FLAGS.SILENT <flag list> Equivalent to -FLAGS, but without -FLAGS.SILENT <flag list>
returning a new value. Equivalent to -FLAGS, but without returning a new value.
Example: C: A003 STORE 2:4 +FLAGS (\Deleted) Example:
S: * 2 FETCH (FLAGS (\Deleted \Seen))
S: * 3 FETCH (FLAGS (\Deleted)) C: A003 STORE 2:4 +FLAGS (\Deleted)
S: * 4 FETCH (FLAGS (\Deleted \Flagged \Seen)) S: * 2 FETCH (FLAGS (\Deleted \Seen))
S: A003 OK STORE completed S: * 3 FETCH (FLAGS (\Deleted))
S: * 4 FETCH (FLAGS (\Deleted \Flagged \Seen))
S: A003 OK STORE completed
6.4.7. COPY Command 6.4.7. COPY Command
Arguments: sequence set Arguments: sequence set
mailbox name
Responses: no specific responses for this command mailbox name
Result: OK - copy completed Responses: no specific responses for this command
NO - copy error: can't copy those messages or to that
name Result: OK - copy completed
BAD - command unknown or arguments invalid NO - copy error: can't copy those messages or to that
name
BAD - command unknown or arguments invalid
The COPY command copies the specified message(s) to the end of the The COPY command copies the specified message(s) to the end of the
specified destination mailbox. The flags and internal date of the specified destination mailbox. The flags and internal date of the
message(s) SHOULD be preserved in the copy. message(s) SHOULD be preserved in the copy.
If the destination mailbox does not exist, a server MUST return an If the destination mailbox does not exist, a server MUST return an
error. It MUST NOT automatically create the mailbox. Unless it is error. It MUST NOT automatically create the mailbox. Unless it is
certain that the destination mailbox can not be created, the server certain that the destination mailbox can not be created, the server
MUST send the response code "[TRYCREATE]" as the prefix of the text MUST send the response code "[TRYCREATE]" as the prefix of the text
of the tagged NO response. This gives a hint to the client that it of the tagged NO response. This gives a hint to the client that it
can attempt a CREATE command and retry the COPY if the CREATE is can attempt a CREATE command and retry the COPY if the CREATE is
successful. successful.
If the COPY command is unsuccessful for any reason, server If the COPY command is unsuccessful for any reason, server
implementations MUST restore the destination mailbox to its state implementations MUST restore the destination mailbox to its state
before the COPY attempt (other than possibly incrementing UIDNEXT), before the COPY attempt (other than possibly incrementing UIDNEXT),
i.e. partial copy MUST NOT be done. i.e., partial copy MUST NOT be done.
On successful completion of a COPY, the server returns a COPYUID On successful completion of a COPY, the server returns a COPYUID
response code (see Section 7.1). Two exception to this requirement response code (see Section 7.1). Two exceptions to this requirement
are listed below. are listed below.
In the case of a mailbox that has permissions set so that the client In the case of a mailbox that has permissions set so that the client
can COPY to the mailbox, but not SELECT or EXAMINE it, the server can COPY to the mailbox, but not SELECT or EXAMINE it, the server
MUST NOT send an COPYUID response code as it would disclose MUST NOT send a COPYUID response code as it would disclose
information about the mailbox. information about the mailbox.
In the case of a mailbox that has UIDNOTSTICKY status (see In the case of a mailbox that has UIDNOTSTICKY status (see
Section 7.1), the server MAY omit the COPYUID response code as it is Section 7.1), the server MAY omit the COPYUID response code as it is
not meaningful. not meaningful.
Example: C: A003 COPY 2:4 MEETING Example:
S: A003 OK [COPYUID 38505 304,319:320 3956:3958] COPY completed
C: A003 COPY 2:4 MEETING
S: A003 OK [COPYUID 38505 304,319:320 3956:3958] COPY completed
6.4.8. MOVE Command 6.4.8. MOVE Command
Arguments: sequence set Arguments: sequence set
mailbox name
Responses: no specific responses for this command mailbox name
Result: OK - move completed Responses: no specific responses for this command
NO - move error: can't move those messages or to that
name Result: OK - move completed
BAD - command unknown or arguments invalid NO - move error: can't move those messages or to that
name
BAD - command unknown or arguments invalid
The MOVE command moves the specified message(s) to the end of the The MOVE command moves the specified message(s) to the end of the
specified destination mailbox. The flags and internal date of the specified destination mailbox. The flags and internal date of the
message(s) SHOULD be preserved. message(s) SHOULD be preserved.
This means that a new message is created in the target mailbox with a This means that a new message is created in the target mailbox with a
new UID, the original message is removed from the source mailbox, and new UID, the original message is removed from the source mailbox, and
it appears to the client as a single action. This has the same it appears to the client as a single action. This has the same
effect for each message as this sequence: effect for each message as this sequence:
1. [UID] COPY 1. [UID] COPY
2. [UID] STORE +FLAGS.SILENT \DELETED 2. [UID] STORE +FLAGS.SILENT \DELETED
3. UID EXPUNGE 3. UID EXPUNGE
Although the effect of the MOVE is the same as the preceding steps, Although the effect of the MOVE is the same as the preceding steps,
the semantics are not identical: The intermediate states produced by the semantics are not identical: the intermediate states produced by
those steps do not occur, and the response codes are different. In those steps do not occur, and the response codes are different. In
particular, though the COPY and EXPUNGE response codes will be particular, though the COPY and EXPUNGE response codes will be
returned, response codes for a STORE MUST NOT be generated and the returned, response codes for a STORE MUST NOT be generated, and the
\Deleted flag MUST NOT be set for any message. \Deleted flag MUST NOT be set for any message.
Unlike the COPY command, MOVE of a set of messages might fail partway Unlike the COPY command, MOVE of a set of messages might fail partway
through the set. Regardless of whether the command is successful in through the set. Regardless of whether the command is successful in
moving the entire set, each individual message MUST either be moved moving the entire set, each individual message MUST be either moved
or unaffected. The server MUST leave each message in a state where or unaffected. The server MUST leave each message in a state where
it is in at least one of the source or target mailboxes (no message it is in at least one of the source or target mailboxes (no message
can be lost or orphaned). The server SHOULD NOT leave any message in can be lost or orphaned). The server SHOULD NOT leave any message in
both mailboxes (it would be bad for a partial failure to result in a both mailboxes (it would be bad for a partial failure to result in a
bunch of duplicate messages). This is true even if the server bunch of duplicate messages). This is true even if the server
returns a tagged NO response to the command. returns a tagged NO response to the command.
If the destination mailbox does not exist, a server MUST return an If the destination mailbox does not exist, a server MUST return an
error. It MUST NOT automatically create the mailbox. Unless it is error. It MUST NOT automatically create the mailbox. Unless it is
certain that the destination mailbox can not be created, the server certain that the destination mailbox cannot be created, the server
MUST send the response code "[TRYCREATE]" as the prefix of the text MUST send the response code "[TRYCREATE]" as the prefix of the text
of the tagged NO response. This gives a hint to the client that it of the tagged NO response. This gives a hint to the client that it
can attempt a CREATE command and retry the MOVE if the CREATE is can attempt a CREATE command and retry the MOVE if the CREATE is
successful. successful.
Because of the similarity of MOVE to COPY, extensions that affect Because of the similarity of MOVE to COPY, extensions that affect
COPY affect MOVE in the same way. Response codes listed in COPY affect MOVE in the same way. Response codes listed in
Section 7.1, as well as those defined by extensions, are sent as Section 7.1, as well as those defined by extensions, are sent as
indicated for COPY. indicated for COPY.
Servers send COPYUID in response to a MOVE or a UID MOVE (see Servers send COPYUID in response to a MOVE or a UID MOVE (see
Section 6.4.9) command. For additional information about COPYUID see Section 6.4.9) command. For additional information about COPYUID,
Section 7.1. Note that there are several exceptions listed in see Section 7.1. Note that there are several exceptions listed in
Section 6.4.7 that allow servers not to return COPYUID. Section 6.4.7 that allow servers not to return COPYUID.
Servers are also REQUIRED to send the COPYUID response code in an Servers are also REQUIRED to send the COPYUID response code in an
untagged OK before sending EXPUNGE or similar responses. (Sending untagged OK before sending EXPUNGE or similar responses. (Sending
COPYUID in the tagged OK, as described in the UIDPLUS specification, COPYUID in the tagged OK, as described in Section 6.4.7, means that
means that clients first receive an EXPUNGE for a message and clients first receive an EXPUNGE for a message and afterwards COPYUID
afterwards COPYUID for the same message. It can be unnecessarily for the same message. It can be unnecessarily difficult to process
difficult to process that sequence usefully.) that sequence usefully.)
An example: An example:
C: a UID MOVE 42:69 foo
S: * OK [COPYUID 432432 42:69 1202:1229] C: a UID MOVE 42:69 foo
S: * 22 EXPUNGE S: * OK [COPYUID 432432 42:69 1202:1229]
...More EXPUNGE responses from the server... S: * 22 EXPUNGE
S: a OK Done ...More EXPUNGE responses from the server...
S: a OK Done
Note that the server may send unrelated EXPUNGE responses as well, if Note that the server may send unrelated EXPUNGE responses as well, if
any happen to have been expunged at the same time; this is normal any happen to have been expunged at the same time; this is normal
IMAP operation. IMAP operation.
Note that moving a message to the currently selected mailbox (that Note that moving a message to the currently selected mailbox (that
is, where the source and target mailboxes are the same) is allowed is, where the source and target mailboxes are the same) is allowed
when copying the message to the currently selected mailbox is when copying the message to the currently selected mailbox is
allowed. allowed.
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the client cannot safely send more commands with message sequence the client cannot safely send more commands with message sequence
number arguments while the server is processing MOVE. number arguments while the server is processing MOVE.
MOVE and UID MOVE can be pipelined with other commands, but care has MOVE and UID MOVE can be pipelined with other commands, but care has
to be taken. Both commands modify sequence numbers and also allow to be taken. Both commands modify sequence numbers and also allow
unrelated EXPUNGE responses. The renumbering of other messages in unrelated EXPUNGE responses. The renumbering of other messages in
the source mailbox following any EXPUNGE response can be surprising the source mailbox following any EXPUNGE response can be surprising
and makes it unsafe to pipeline any command that relies on message and makes it unsafe to pipeline any command that relies on message
sequence numbers after a MOVE or UID MOVE. Similarly, MOVE cannot be sequence numbers after a MOVE or UID MOVE. Similarly, MOVE cannot be
pipelined with a command that might cause message renumbering. See pipelined with a command that might cause message renumbering. See
Section 5.5, for more information about ambiguities as well as Section 5.5 for more information about ambiguities as well as
handling requirements for both clients and servers. handling requirements for both clients and servers.
6.4.9. UID Command 6.4.9. UID Command
Arguments: command name Arguments: command name
command arguments
Responses: untagged responses: FETCH, ESEARCH, EXPUNGE command arguments
Result: OK - UID command completed Responses: untagged responses: FETCH, ESEARCH, EXPUNGE
NO - UID command error
BAD - command unknown or arguments invalid Result: OK - UID command completed
NO - UID command error
BAD - command unknown or arguments invalid
The UID command has three forms. In the first form, it takes as its The UID command has three forms. In the first form, it takes as its
arguments a COPY, MOVE, FETCH, or STORE command with arguments arguments a COPY, MOVE, FETCH, or STORE command with arguments
appropriate for the associated command. However, the numbers in the appropriate for the associated command. However, the numbers in the
sequence set argument are unique identifiers instead of message sequence-set argument are unique identifiers instead of message
sequence numbers. Sequence set ranges are permitted, but there is no sequence numbers. Sequence-set ranges are permitted, but there is no
guarantee that unique identifiers will be contiguous. guarantee that unique identifiers will be contiguous.
A non-existent unique identifier is ignored without any error message A non-existent unique identifier is ignored without any error message
generated. Thus, it is possible for a UID FETCH command to return an generated. Thus, it is possible for a UID FETCH command to return an
OK without any data or a UID COPY, UID MOVE or UID STORE to return an OK without any data or a UID COPY, UID MOVE, or UID STORE to return
OK without performing any operations. an OK without performing any operations.
In the second form, the UID command takes an EXPUNGE command with an In the second form, the UID command takes an EXPUNGE command with an
extra parameter the specified a sequence set of UIDs to operate on. extra parameter that specifies a sequence set of UIDs to operate on.
The UID EXPUNGE command permanently removes all messages that both The UID EXPUNGE command permanently removes all messages that have
have the \Deleted flag set and have a UID that is included in the both the \Deleted flag set and a UID that is included in the
specified sequence set from the currently selected mailbox. If a specified sequence set from the currently selected mailbox. If a
message either does not have the \Deleted flag set or has a UID that message either does not have the \Deleted flag set or has a UID that
is not included in the specified sequence set, it is not affected. is not included in the specified sequence set, it is not affected.
UID EXPUNGE is particularly useful for disconnected use clients. UID EXPUNGE is particularly useful for disconnected use clients. By
By using UID EXPUNGE instead of EXPUNGE when resynchronizing with using UID EXPUNGE instead of EXPUNGE when resynchronizing with the
the server, the client can ensure that it does not inadvertantly server, the client can ensure that it does not inadvertently remove
remove any messages that have been marked as \Deleted by other any messages that have been marked as \Deleted by other clients
clients between the time that the client was last connected and between the time that the client was last connected and the time the
the time the client resynchronizes. client resynchronizes.
Example: C: A003 UID EXPUNGE 3000:3002 Example:
S: * 3 EXPUNGE
S: * 3 EXPUNGE C: A003 UID EXPUNGE 3000:3002
S: * 3 EXPUNGE S: * 3 EXPUNGE
S: A003 OK UID EXPUNGE completed S: * 3 EXPUNGE
S: * 3 EXPUNGE
S: A003 OK UID EXPUNGE completed
In the third form, the UID command takes a SEARCH command with SEARCH In the third form, the UID command takes a SEARCH command with SEARCH
command arguments. The interpretation of the arguments is the same command arguments. The interpretation of the arguments is the same
as with SEARCH; however, the numbers returned in a ESEARCH response as with SEARCH; however, the numbers returned in an ESEARCH response
for a UID SEARCH command are unique identifiers instead of message for a UID SEARCH command are unique identifiers instead of message
sequence numbers. Also, the corresponding ESEARCH response MUST sequence numbers. Also, the corresponding ESEARCH response MUST
include the UID indicator. For example, the command UID SEARCH 1:100 include the UID indicator. For example, the command UID SEARCH 1:100
UID 443:557 returns the unique identifiers corresponding to the UID 443:557 returns the unique identifiers corresponding to the
intersection of two sequence sets, the message sequence number range intersection of two sequence sets, the message sequence number range
1:100 and the UID range 443:557. 1:100, and the UID range 443:557.
Note: in the above example, the UID range 443:557 appears. The Note: in the above example, the UID range 443:557 appears. The
same comment about a non-existent unique identifier being ignored same comment about a non-existent unique identifier being ignored
without any error message also applies here. Hence, even if without any error message also applies here. Hence, even if
neither UID 443 or 557 exist, this range is valid and would neither UID 443 or 557 exist, this range is valid and would
include an existing UID 495. include an existing UID 495.
Also note that a UID range of 559:* always includes the UID of the Also note that a UID range of 559:* always includes the UID of the
last message in the mailbox, even if 559 is higher than any last message in the mailbox, even if 559 is higher than any
assigned UID value. This is because the contents of a range are assigned UID value. This is because the contents of a range are
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response caused by a UID command, regardless of whether a UID was response caused by a UID command, regardless of whether a UID was
specified as a message data item to the FETCH. specified as a message data item to the FETCH.
Note: The rule about including the UID message data item as part of a Note: The rule about including the UID message data item as part of a
FETCH response primarily applies to the UID FETCH and UID STORE FETCH response primarily applies to the UID FETCH and UID STORE
commands, including a UID FETCH command that does not include UID as commands, including a UID FETCH command that does not include UID as
a message data item. Although it is unlikely that the other UID a message data item. Although it is unlikely that the other UID
commands will cause an untagged FETCH, this rule applies to these commands will cause an untagged FETCH, this rule applies to these
commands as well. commands as well.
Example: C: A999 UID FETCH 4827313:4828442 FLAGS Example:
S: * 23 FETCH (FLAGS (\Seen) UID 4827313)
S: * 24 FETCH (FLAGS (\Seen) UID 4827943) C: A999 UID FETCH 4827313:4828442 FLAGS
S: * 25 FETCH (FLAGS (\Seen) UID 4828442) S: * 23 FETCH (FLAGS (\Seen) UID 4827313)
S: A999 OK UID FETCH completed S: * 24 FETCH (FLAGS (\Seen) UID 4827943)
S: * 25 FETCH (FLAGS (\Seen) UID 4828442)
S: A999 OK UID FETCH completed
6.5. Client Commands - Experimental/Expansion 6.5. Client Commands - Experimental/Expansion
Each command which is not part of this specification MUST have at Each command that is not part of this specification MUST have at
least one capability name (see Section 6.1.1) associated with it. least one capability name (see Section 6.1.1) associated with it.
(Multiple commands can be associated with the same capability name.) (Multiple commands can be associated with the same capability name.)
Server implementations MUST NOT send any added (not specified in this Server implementations MUST NOT send any added untagged responses
specification) untagged responses, unless the client requested it by (not specified in this specification), unless the client requested it
issuing the associated experimental command (specified in an by issuing the associated experimental command (specified in an
extension document) or the ENABLE command (Section 6.3.1). extension document) or the ENABLE command (Section 6.3.1).
The following example demonstrates how a client can check for The following example demonstrates how a client can check for the
presence of a fictitious XPIG-LATIN capability that adds the XPIG- presence of a fictitious XPIG-LATIN capability that adds the XPIG-
LATIN command and the the XPIG-LATIN untagged response. (Note that LATIN command and the XPIG-LATIN untagged response. (Note that for
for an extension the command name and the capability name don't have an extension, the command name and the capability name don't have to
to be the same.) be the same.)
Example: C: a441 CAPABILITY Example:
S: * CAPABILITY IMAP4rev2 XPIG-LATIN
S: a441 OK CAPABILITY completed C: a441 CAPABILITY
C: A442 XPIG-LATIN S: * CAPABILITY IMAP4rev2 XPIG-LATIN
S: * XPIG-LATIN ow-nay eaking-spay ig-pay atin-lay S: a441 OK CAPABILITY completed
S: A442 OK XPIG-LATIN ompleted-cay C: A442 XPIG-LATIN
S: * XPIG-LATIN ow-nay eaking-spay ig-pay atin-lay
S: A442 OK XPIG-LATIN ompleted-cay
7. Server Responses 7. Server Responses
Server responses are in three forms: status responses, server data, Server responses are in three forms: status responses, server data,
and command continuation request. The information contained in a and command continuation requests. The information contained in a
server response, identified by "Contents:" in the response server response, identified by "Contents:" in the response
descriptions below, is described by function, not by syntax. The descriptions below, is described by function, not by syntax. The
precise syntax of server responses is described in the Formal Syntax precise syntax of server responses is described in "Formal Syntax"
(Section 9). (Section 9).
The client MUST be prepared to accept any response at all times. The client MUST be prepared to accept any response at all times.
Status responses can be tagged or untagged. Tagged status responses Status responses can be tagged or untagged. Tagged status responses
indicate the completion result (OK, NO, or BAD status) of a client indicate the completion result (OK, NO, or BAD status) of a client
command, and have a tag matching the command. command and have a tag matching the command.
Some status responses, and all server data, are untagged. An Some status responses, and all server data, are untagged. An
untagged response is indicated by the token "*" instead of a tag. untagged response is indicated by the token "*" instead of a tag.
Untagged status responses indicate server greeting, or server status Untagged status responses indicate server greeting or server status
that does not indicate the completion of a command (for example, an that does not indicate the completion of a command (for example, an
impending system shutdown alert). For historical reasons, untagged impending system shutdown alert). For historical reasons, untagged
server data responses are also called "unsolicited data", although server data responses are also called "unsolicited data", although
strictly speaking, only unilateral server data is truly strictly speaking, only unilateral server data is truly
"unsolicited". "unsolicited".
Certain server data MUST be remembered by the client when it is Certain server data MUST be remembered by the client when it is
received; this is noted in the description of that data. Such data received; this is noted in the description of that data. Such data
conveys critical information which affects the interpretation of all conveys critical information that affects the interpretation of all
subsequent commands and responses (e.g., updates reflecting the subsequent commands and responses (e.g., updates reflecting the
creation or destruction of messages). creation or destruction of messages).
Other server data SHOULD be remembered for later reference; if the Other server data SHOULD be remembered for later reference; if the
client does not need to remember the data, or if remembering the data client does not need to remember the data, or if remembering the data
has no obvious purpose (e.g., a SEARCH response when no SEARCH has no obvious purpose (e.g., a SEARCH response when no SEARCH
command is in progress), the data can be ignored. command is in progress), the data can be ignored.
An example of unilateral untagged server data occurs when the IMAP An example of unilateral untagged server data occurs when the IMAP
connection is in the selected state. In the selected state, the connection is in the selected state. In the selected state, the
server checks the mailbox for new messages as part of command server checks the mailbox for new messages as part of command
execution. Normally, this is part of the execution of every command; execution. Normally, this is part of the execution of every command;
hence, a NOOP command suffices to check for new messages. If new hence, a NOOP command suffices to check for new messages. If new
messages are found, the server sends untagged EXISTS response messages are found, the server sends an untagged EXISTS response
reflecting the new size of the mailbox. Server implementations that reflecting the new size of the mailbox. Server implementations that
offer multiple simultaneous access to the same mailbox SHOULD also offer multiple simultaneous access to the same mailbox SHOULD also
send appropriate unilateral untagged FETCH and EXPUNGE responses if send appropriate unilateral untagged FETCH and EXPUNGE responses if
another agent changes the state of any message flags or expunges any another agent changes the state of any message flags or expunges any
messages. messages.
Command continuation request responses use the token "+" instead of a Command continuation request responses use the token "+" instead of a
tag. These responses are sent by the server to indicate acceptance tag. These responses are sent by the server to indicate acceptance
of an incomplete client command and readiness for the remainder of of an incomplete client command and readiness for the remainder of
the command. the command.
7.1. Server Responses - Generic Status Responses 7.1. Server Responses - Generic Status Responses
Status responses are OK, NO, BAD, PREAUTH and BYE. OK, NO, and BAD Status responses are OK, NO, BAD, PREAUTH, and BYE. OK, NO, and BAD
can be tagged or untagged. PREAUTH and BYE are always untagged. can be tagged or untagged. PREAUTH and BYE are always untagged.
Status responses MAY include an OPTIONAL "response code". A response Status responses MAY include an OPTIONAL "response code". A response
code consists of data inside square brackets in the form of an atom, code consists of data inside square brackets in the form of an atom,
possibly followed by a space and arguments. The response code possibly followed by a space and arguments. The response code
contains additional information or status codes for client software contains additional information or status codes for client software
beyond the OK/NO/BAD condition, and are defined when there is a beyond the OK/NO/BAD condition and are defined when there is a
specific action that a client can take based upon the additional specific action that a client can take based upon the additional
information. information.
The currently defined response codes are: The currently defined response codes are:
ALERT ALERT
The human-readable text contains a special alert that is presented
The human-readable text contains a special alert that are to the user in a fashion that calls the user's attention to the
presented to the user in a fashion that calls the user's message. Content of ALERT response codes received on a connection
attention to the message. Content of ALERT response codes without TLS or SASL security-layer confidentiality SHOULD be
received on a connection without TLS or SASL security layer ignored by clients. If displayed, such alerts MUST be clearly
confidentiality SHOULD be ignored by clients. If displayed, marked as potentially suspicious. (Note that some existing
such alerts MUST be clearly marked as potentially suspicious. clients are known to hyperlink returned text, which make them very
(Note that some existing clients are known to hyperlink dangerous.) Alerts received after successful establishment of a
returned text which make them very dangerous.) Alerts received TLS/SASL confidentiality layer MUST be presented to the user.
after successful establishment of a TLS/SASL confidentiality
layer MUST be presented to the user.
ALREADYEXISTS ALREADYEXISTS
The operation attempts to create something that already exists,
such as when a CREATE or RENAME command attempts to create a
mailbox and there is already one of that name.
The operation attempts to create something that already exists, C: o356 RENAME this that
such as when the CREATE or RENAME directories attempt to create S: o356 NO [ALREADYEXISTS] Mailbox "that" already exists
a mailbox and there is already one of that name.
C: o356 RENAME this that
S: o356 NO [ALREADYEXISTS] Mailbox "that" already exists
APPENDUID APPENDUID
Followed by the UIDVALIDITY of the destination mailbox and the UID
assigned to the appended message in the destination mailbox, it
indicates that the message has been appended to the destination
mailbox with that UID.
Followed by the UIDVALIDITY of the destination mailbox and the If the server also supports the [MULTIAPPEND] extension, and if
UID assigned to the appended message in the destination multiple messages were appended in the APPEND command, then the
mailbox, indicates that the message has been appended to the second value is a UID set containing the UIDs assigned to the
destination mailbox with that UID. appended messages, in the order they were transmitted in the
APPEND command. This UID set may not contain extraneous UIDs or
If the server also supports the [MULTIAPPEND] extension, and if the symbol "*".
multiple messages were appended in the APPEND command, then the
second value is a UID set containing the UIDs assigned to the
appended messages, in the order they were transmitted in the
APPEND command. This UID set may not contain extraneous UIDs
or the symbol "*".
Note: the UID set form of the APPENDUID response code MUST Note: the UID set form of the APPENDUID response code MUST NOT
NOT be used if only a single message was appended. In be used if only a single message was appended. In particular,
particular, a server MUST NOT send a range such as 123:123. a server MUST NOT send a range such as 123:123. This is
This is because a client that does not support [MULTIAPPEND] because a client that does not support [MULTIAPPEND] expects
expects only a single UID and not a UID set. only a single UID and not a UID set.
UIDs are assigned in strictly ascending order in the mailbox UIDs are assigned in strictly ascending order in the mailbox
(refer to Section 2.3.1.1); note that a range of 12:10 is (refer to Section 2.3.1.1); note that a range of 12:10 is exactly
exactly equivalent to 10:12 and refers to the sequence equivalent to 10:12 and refers to the sequence 10,11,12.
10,11,12.
This response code is returned in a tagged OK response to the This response code is returned in a tagged OK response to the
APPEND command. APPEND command.
AUTHENTICATIONFAILED AUTHENTICATIONFAILED
Authentication failed for some reason on which the server is
unwilling to elaborate. Typically, this includes "unknown user"
and "bad password".
Authentication failed for some reason on which the server is This is the same as not sending any response code, except that
unwilling to elaborate. Typically, this includes "unknown when a client sees AUTHENTICATIONFAILED, it knows that the problem
user" and "bad password". wasn't, e.g., UNAVAILABLE, so there's no point in trying the same
login/password again later.
This is the same as not sending any response code, except that
when a client sees AUTHENTICATIONFAILED, it knows that the
problem wasn't, e.g., UNAVAILABLE, so there's no point in
trying the same login/password again later.
C: b LOGIN "fred" "foo" C: b LOGIN "fred" "foo"
S: b NO [AUTHENTICATIONFAILED] Authentication failed S: b NO [AUTHENTICATIONFAILED] Authentication failed
AUTHORIZATIONFAILED AUTHORIZATIONFAILED
Authentication succeeded in using the authentication identity, but
the server cannot or will not allow the authentication identity to
act as the requested authorization identity. This is only
applicable when the authentication and authorization identities
are different.
Authentication succeeded in using the authentication identity, C: c1 AUTHENTICATE PLAIN
but the server cannot or will not allow the authentication [...]
identity to act as the requested authorization identity. This S: c1 NO [AUTHORIZATIONFAILED] No such authorization-ID
is only applicable when the authentication and authorization
identities are different.
C: c1 AUTHENTICATE PLAIN
[...]
S: c1 NO [AUTHORIZATIONFAILED] No such authorization-ID
C: c2 AUTHENTICATE PLAIN C: c2 AUTHENTICATE PLAIN
[...] [...]
S: c2 NO [AUTHORIZATIONFAILED] Authenticator is not an admin S: c2 NO [AUTHORIZATIONFAILED] Authenticator is not an admin
BADCHARSET BADCHARSET
Optionally followed by a parenthesized list of charsets. A SEARCH
Optionally followed by a parenthesized list of charsets. A failed because the given charset is not supported by this
SEARCH failed because the given charset is not supported by implementation. If the optional list of charsets is given, this
this implementation. If the optional list of charsets is lists the charsets that are supported by this implementation.
given, this lists the charsets that are supported by this
implementation.
CANNOT CANNOT
This operation violates some invariant of the server and can never
succeed.
The operation violates some invariant of the server and can C: l create "///////"
never succeed. S: l NO [CANNOT] Adjacent slashes are not supported
C: l create "///////"
S: l NO [CANNOT] Adjacent slashes are not supported
CAPABILITY CAPABILITY
Followed by a list of capabilities. This can appear in the
Followed by a list of capabilities. This can appear in the initial OK or PREAUTH response to transmit an initial capabilities
initial OK or PREAUTH response to transmit an initial list. It can also appear in tagged responses to LOGIN or
capabilities list. It can also appear in tagged responses to AUTHENTICATE commands. This makes it unnecessary for a client to
LOGIN or AUTHENTICATE commands. This makes it unnecessary for send a separate CAPABILITY command if it recognizes this response
a client to send a separate CAPABILITY command if it recognizes code and there was no change to the TLS and/or authentication
this response code and there was no change to the TLS and/or state since it was received.
authentication state since it was received.
CLIENTBUG CLIENTBUG
The server has detected a client bug. This can accompany any of
OK, NO, and BAD, depending on what the client bug is.
The server has detected a client bug. This can accompany all C: k1 select "/archive/projects/experiment-iv"
of OK, NO, and BAD, depending on what the client bug is. [...]
S: k1 OK [READ-ONLY] Done
C: k1 select "/archive/projects/experiment-iv" C: k2 status "/archive/projects/experiment-iv" (messages)
[...] [...]
S: k1 OK [READ-ONLY] Done S: k2 OK [CLIENTBUG] Done
C: k2 status "/archive/projects/experiment-iv" (messages)
[...]
S: k2 OK [CLIENTBUG] Done
CLOSED CLOSED
The CLOSED response code has no parameters. A server returns the
CLOSED response code when the currently selected mailbox is closed
implicitly using the SELECT or EXAMINE command on another mailbox.
The CLOSED response code serves as a boundary between responses
for the previously opened mailbox (which was closed) and the newly
selected mailbox; all responses before the CLOSED response code
relate to the mailbox that was closed, and all subsequent
responses relate to the newly opened mailbox.
The CLOSED response code has no parameters. A server return There is no need to return the CLOSED response code on completion
the CLOSED response code when the currently selected mailbox is of the CLOSE or the UNSELECT command (or similar), whose purpose
closed implicitly using the SELECT/EXAMINE command on another is to close the currently selected mailbox without opening a new
mailbox. The CLOSED response code serves as a boundary between one.
responses for the previously opened mailbox (which was closed)
and the newly selected mailbox; all responses before the CLOSED
response code relate to the mailbox that was closed, and all
subsequent responses relate to the newly opened mailbox.
There is no need to return the CLOSED response code on
completion of the CLOSE or the UNSELECT command (or similar),
whose purpose is to close the currently selected mailbox
without opening a new one.
CONTACTADMIN CONTACTADMIN
The user should contact the system administrator or support desk.
The user should contact the system administrator or support C: e login "fred" "foo"
desk. S: e NO [CONTACTADMIN]
C: e login "fred" "foo"
S: e NO [CONTACTADMIN]
COPYUID COPYUID
Followed by the UIDVALIDITY of the destination mailbox, a UID set
containing the UIDs of the message(s) in the source mailbox that
were copied to the destination mailbox, followed by another UID
set containing the UIDs assigned to the copied message(s) in the
destination mailbox, indicates that the message(s) has been copied
to the destination mailbox with the stated UID(s).
Followed by the UIDVALIDITY of the destination mailbox, a UID The source UID set is in the order the message(s) was copied; the
set containing the UIDs of the message(s) in the source mailbox destination UID set corresponds to the source UID set and is in
that were copied to the destination mailbox, followed by the same order. Neither of the UID sets may contain extraneous
another UID set containing the UIDs assigned to the copied UIDs or the symbol "*".
message(s) in the destination mailbox, indicates that the
message(s) have been copied to the destination mailbox with the
stated UID(s).
The source UID set is in the order the message(s) were copied;
the destination UID set corresponds to the source UID set and
is in the same order. Neither of the UID sets may contain
extraneous UIDs or the symbol "*".
UIDs are assigned in strictly ascending order in the mailbox UIDs are assigned in strictly ascending order in the mailbox
(refer to Section 2.3.1.1); note that a range of 12:10 is (refer to Section 2.3.1.1); note that a range of 12:10 is exactly
exactly equivalent to 10:12 and refers to the sequence equivalent to 10:12 and refers to the sequence 10,11,12.
10,11,12.
This response code is returned in a tagged OK response to the This response code is returned in a tagged OK response to the COPY
COPY/UID COPY command or in the untagged OK response to the or UID COPY command or in the untagged OK response to the MOVE or
MOVE/UID MOVE command. UID MOVE command.
CORRUPTION CORRUPTION
The server discovered that some relevant data (e.g., the mailbox)
are corrupt. This response code does not include any information
about what's corrupt, but the server can write that to its
logfiles.
The server discovered that some relevant data (e.g., the C: i select "/archive/projects/experiment-iv"
mailbox) are corrupt. This response code does not include any S: i NO [CORRUPTION] Cannot open mailbox
information about what's corrupt, but the server can write that
to its logfiles.
C: i select "/archive/projects/experiment-iv"
S: i NO [CORRUPTION] Cannot open mailbox
EXPIRED EXPIRED
Either authentication succeeded or the server no longer had the
necessary data; either way, access is no longer permitted using
that passphrase. The client or user should get a new passphrase.
Either authentication succeeded or the server no longer had the C: d login "fred" "foo"
necessary data; either way, access is no longer permitted using S: d NO [EXPIRED] That password isn't valid any more
that passphrase. The client or user should get a new
passphrase.
C: d login "fred" "foo"
S: d NO [EXPIRED] That password isn't valid any more
EXPUNGEISSUED EXPUNGEISSUED
Someone else has issued an EXPUNGE for the same mailbox. The Someone else has issued an EXPUNGE for the same mailbox. The
client may want to issue NOOP soon. [IMAP-MULTIACCESS] client may want to issue NOOP soon. [IMAP-MULTIACCESS] discusses
discusses this subject in depth. this subject in depth.
C: h search from maria@example.com C: h search from maria@example.com
S: * ESEARCH (TAG "h") ALL 1:3,5,8,13,21,42 S: * ESEARCH (TAG "h") ALL 1:3,5,8,13,21,42
S: h OK [EXPUNGEISSUED] Search completed S: h OK [EXPUNGEISSUED] Search completed
HASCHILDREN HASCHILDREN
The mailbox delete operation failed because the mailbox has one or
more children, and the server doesn't allow deletion of mailboxes
with children.
The mailbox delete operation failed because the mailbox has one C: m356 DELETE Notes
or more children and the server doesn't allow deletion of S: o356 NO [HASCHILDREN] Mailbox "Notes" has children
mailboxes with children. that need to be deleted first
C: m356 DELETE Notes
S: o356 NO [HASCHILDREN] Mailbox "Notes" has children that need
to be deleted first
INUSE INUSE
An operation has not been carried out because it involves sawing
off a branch someone else is sitting on. Someone else may be
holding an exclusive lock needed for this operation, or the
operation may involve deleting a resource someone else is using,
typically a mailbox.
An operation has not been carried out because it involves The operation may succeed if the client tries again later.
sawing off a branch someone else is sitting on. Someone else
may be holding an exclusive lock needed for this operation, or
the operation may involve deleting a resource someone else is
using, typically a mailbox.
The operation may succeed if the client tries again later.
C: g delete "/archive/projects/experiment-iv" C: g delete "/archive/projects/experiment-iv"
S: g NO [INUSE] Mailbox in use S: g NO [INUSE] Mailbox in use
LIMIT LIMIT
The operation ran up against an implementation limit of some kind,
such as the number of flags on a single message or the number of
flags used in a mailbox.
The operation ran up against an implementation limit of some C: m STORE 42 FLAGS f1 f2 f3 f4 f5 ... f250
kind, such as the number of flags on a single message or the S: m NO [LIMIT] At most 32 flags in one mailbox supported
number of flags used in a mailbox.
C: m STORE 42 FLAGS f1 f2 f3 f4 f5 ... f250
S: m NO [LIMIT] At most 32 flags in one mailbox supported
NONEXISTENT NONEXISTENT
The operation attempts to delete something that does not exist.
Similar to ALREADYEXISTS.
The operation attempts to delete something that does not exist. C: p RENAME this that
Similar to ALREADYEXISTS. S: p NO [NONEXISTENT] No such mailbox
C: p RENAME this that
S: p NO [NONEXISTENT] No such mailbox
NOPERM NOPERM
The access control system (e.g., ACL; see [RFC4314]) does not
permit this user to carry out an operation, such as selecting or
creating a mailbox.
The access control system (e.g., Access Control List (ACL), see C: f select "/archive/projects/experiment-iv"
[RFC4314]) does not permit this user to carry out an operation, S: f NO [NOPERM] Access denied
such as selecting or creating a mailbox.
C: f select "/archive/projects/experiment-iv"
S: f NO [NOPERM] Access denied
OVERQUOTA OVERQUOTA
The user would be over quota after the operation. (The user may
or may not be over quota already.)
The user would be over quota after the operation. (The user Note that if the server sends OVERQUOTA but doesn't support the
may or may not be over quota already.) IMAP QUOTA extension defined by [RFC2087], then there is a quota,
but the client cannot find out what the quota is.
Note that if the server sends OVERQUOTA but doesn't support the
IMAP QUOTA extension defined by [RFC2087], then there is a
quota, but the client cannot find out what the quota is.
C: n1 uid copy 1:* oldmail C: n1 uid copy 1:* oldmail
S: n1 NO [OVERQUOTA] Sorry S: n1 NO [OVERQUOTA] Sorry
C: n2 uid copy 1:* oldmail C: n2 uid copy 1:* oldmail
S: n2 OK [OVERQUOTA] You are now over your soft quota S: n2 OK [OVERQUOTA] You are now over your soft quota
PARSE PARSE
The human-readable text represents an error in parsing the
The human-readable text represents an error in parsing the [RFC5322] header or [MIME-IMB] headers of a message in the
[RFC-5322] header or [MIME-IMB] headers of a message in the mailbox.
mailbox.
PERMANENTFLAGS PERMANENTFLAGS
Followed by a parenthesized list of flags and indicates which of
the known flags the client can change permanently. Any flags that
are in the FLAGS untagged response, but not in the PERMANENTFLAGS
list, cannot be set permanently. The PERMANENTFLAGS list can also
include the special flag \*, which indicates that it is possible
to create new keywords by attempting to store those keywords in
the mailbox. If the client attempts to STORE a flag that is not
in the PERMANENTFLAGS list, the server will either ignore the
change or store the state change for the remainder of the current
session only.
Followed by a parenthesized list of flags, indicates which of There is no need for a server that included the special flag \* to
the known flags the client can change permanently. Any flags return a new PERMANENTFLAGS response code when a new keyword was
that are in the FLAGS untagged response, but not the successfully set on a message upon client request. However, if
PERMANENTFLAGS list, can not be set permanently. The the server has a limit on the number of different keywords that
PERMANENTFLAGS list can also include the special flag \*, which can be stored in a mailbox and that limit is reached, the server
indicates that it is possible to create new keywords by MUST send a new PERMANENTFLAGS response code without the special
attempting to store those keywords in the mailbox. If the flag \*.
client attempts to STORE a flag that is not in the
PERMANENTFLAGS list, the server will either ignore the change
or store the state change for the remainder of the current
session only.
There is no need for a server that included the special flag \*
to return a new PERMANENTFLAGS response code when a new keyword
was successfully set on a message upon client request. However
if the server has a limit on the number of different keywords
that can be stored in a mailbox and that limit is reached, the
server MUST send a new PERMANENTFLAGS response code without the
special flag \*.
PRIVACYREQUIRED PRIVACYREQUIRED
The operation is not permitted due to a lack of data
confidentiality. If TLS is not in use, the client could try
STARTTLS (see Section 6.2.1) or alternatively reconnect on an
Implicit TLS port, and then repeat the operation.
The operation is not permitted due to a lack of data C: d login "fred" "foo"
confidentiality. If Transport Layer Security (TLS) is not in S: d NO [PRIVACYREQUIRED] Connection offers no privacy
use, the client could try STARTTLS (see Section 6.2.1) or
alternatively reconnect on Implicit TLS port, and then repeat
the operation.
C: d login "fred" "foo"
S: d NO [PRIVACYREQUIRED] Connection offers no privacy
C: d select inbox C: d select inbox
S: d NO [PRIVACYREQUIRED] Connection offers no privacy S: d NO [PRIVACYREQUIRED] Connection offers no privacy
READ-ONLY READ-ONLY
The mailbox is selected as read-only, or its access while selected
The mailbox is selected read-only, or its access while selected has changed from read-write to read-only.
has changed from read-write to read-only.
READ-WRITE READ-WRITE
The mailbox is selected as read-write, or its access while
The mailbox is selected read-write, or its access while selected has changed from read-only to read-write.
selected has changed from read-only to read-write.
SERVERBUG SERVERBUG
The server encountered a bug in itself or violated one of its own
invariants.
The server encountered a bug in itself or violated one of its C: j select "/archive/projects/experiment-iv"
own invariants. S: j NO [SERVERBUG] This should not happen
C: j select "/archive/projects/experiment-iv"
S: j NO [SERVERBUG] This should not happen
TRYCREATE TRYCREATE
An APPEND, COPY, or MOVE attempt is failing because the target
An APPEND, COPY or MOVE attempt is failing because the target mailbox does not exist (as opposed to some other reason). This is
mailbox does not exist (as opposed to some other reason). This a hint to the client that the operation can succeed if the mailbox
is a hint to the client that the operation can succeed if the is first created by the CREATE command.
mailbox is first created by the CREATE command.
UIDNEXT UIDNEXT
Followed by a decimal number, indicates the next unique Followed by a decimal number and indicates the next unique
identifier value. Refer to Section 2.3.1.1 for more identifier value. Refer to Section 2.3.1.1 for more information.
information.
UIDNOTSTICKY UIDNOTSTICKY
The selected mailbox is supported by a mail store that does not
support persistent UIDs; that is, UIDVALIDITY will be different
each time the mailbox is selected. Consequently, APPEND or COPY
to this mailbox will not return an APPENDUID or COPYUID response
code.
The selected mailbox is supported by a mail store that does not This response code is returned in an untagged NO response to the
support persistent UIDs; that is, UIDVALIDITY will be different SELECT command.
each time the mailbox is selected. Consequently, APPEND or
COPY to this mailbox will not return an APPENDUID or COPYUID
response code.
This response code is returned in an untagged NO response to
the SELECT command.
Note: servers SHOULD NOT have any UIDNOTSTICKY mail stores. Note: servers SHOULD NOT have any UIDNOTSTICKY mail stores.
This facility exists to support legacy mail stores in which This facility exists to support legacy mail stores in which it
it is technically infeasible to support persistent UIDs. is technically infeasible to support persistent UIDs. This
This should be avoided when designing new mail stores. should be avoided when designing new mail stores.
UIDVALIDITY UIDVALIDITY
Followed by a decimal number and indicates the unique identifier
Followed by a decimal number, indicates the unique identifier validity value. Refer to Section 2.3.1.1 for more information.
validity value. Refer to Section 2.3.1.1 for more information.
UNAVAILABLE UNAVAILABLE
Temporary failure because a subsystem is down. For example, an
IMAP server that uses a Lightweight Directory Access Protocol
(LDAP) or Radius server for authentication might use this response
code when the LDAP/Radius server is down.
Temporary failure because a subsystem is down. For example, an C: a LOGIN "fred" "foo"
IMAP server that uses a Lightweight Directory Access Protocol S: a NO [UNAVAILABLE] User's backend down for maintenance
(LDAP) or Radius server for authentication might use this
response code when the LDAP/Radius server is down.
C: a LOGIN "fred" "foo"
S: a NO [UNAVAILABLE] User's backend down for maintenance
UNKNOWN-CTE UNKNOWN-CTE
The server does not know how to decode the section's Content-
The server does not know how to decode the section's Content- Transfer-Encoding.
Transfer-Encoding.
Client implementations MUST ignore response codes that they do not Client implementations MUST ignore response codes that they do not
recognize. recognize.
7.1.1. OK Response 7.1.1. OK Response
Contents: OPTIONAL response code Contents:
OPTIONAL response code
human-readable text human-readable text
The OK response indicates an information message from the server. The OK response indicates an information message from the server.
When tagged, it indicates successful completion of the associated When tagged, it indicates successful completion of the associated
command. The human-readable text MAY be presented to the user as an command. The human-readable text MAY be presented to the user as an
information message. The untagged form indicates an information-only information message. The untagged form indicates an information-only
message; the nature of the information MAY be indicated by a response message; the nature of the information MAY be indicated by a response
code. code.
The untagged form is also used as one of three possible greetings at The untagged form is also used as one of three possible greetings at
connection startup. It indicates that the connection is not yet connection startup. It indicates that the connection is not yet
authenticated and that a LOGIN or an AUTHENTICATE command is needed. authenticated and that a LOGIN or an AUTHENTICATE command is needed.
Example: S: * OK IMAP4rev2 server ready Example:
C: A001 LOGIN fred blurdybloop
S: * OK [ALERT] System shutdown in 10 minutes S: * OK IMAP4rev2 server ready
S: A001 OK LOGIN Completed C: A001 LOGIN fred blurdybloop
S: * OK [ALERT] System shutdown in 10 minutes
S: A001 OK LOGIN Completed
7.1.2. NO Response 7.1.2. NO Response
Contents: OPTIONAL response code Contents:
OPTIONAL response code
human-readable text human-readable text
The NO response indicates an operational error message from the The NO response indicates an operational error message from the
server. When tagged, it indicates unsuccessful completion of the server. When tagged, it indicates unsuccessful completion of the
associated command. The untagged form indicates a warning; the associated command. The untagged form indicates a warning; the
command can still complete successfully. The human-readable text command can still complete successfully. The human-readable text
describes the condition. describes the condition.
Example: C: A222 COPY 1:2 owatagusiam Example:
S: * NO Disk is 98% full, please delete unnecessary data
S: A222 OK COPY completed C: A222 COPY 1:2 owatagusiam
C: A223 COPY 3:200 blurdybloop S: * NO Disk is 98% full, please delete unnecessary data
S: * NO Disk is 98% full, please delete unnecessary data S: A222 OK COPY completed
S: * NO Disk is 99% full, please delete unnecessary data C: A223 COPY 3:200 blurdybloop
S: A223 NO COPY failed: disk is full S: * NO Disk is 98% full, please delete unnecessary data
S: * NO Disk is 99% full, please delete unnecessary data
S: A223 NO COPY failed: disk is full
7.1.3. BAD Response 7.1.3. BAD Response
Contents: OPTIONAL response code Contents:
OPTIONAL response code
human-readable text human-readable text
The BAD response indicates an error message from the server. When The BAD response indicates an error message from the server. When
tagged, it reports a protocol-level error in the client's command; tagged, it reports a protocol-level error in the client's command;
the tag indicates the command that caused the error. The untagged the tag indicates the command that caused the error. The untagged
form indicates a protocol-level error for which the associated form indicates a protocol-level error for which the associated
command can not be determined; it can also indicate an internal command can not be determined; it can also indicate an internal
server failure. The human-readable text describes the condition. server failure. The human-readable text describes the condition.
Example: C: ...very long command line... Example:
S: * BAD Command line too long
C: ...empty line... C: ...very long command line...
S: * BAD Empty command line S: * BAD Command line too long
C: A443 EXPUNGE C: ...empty line...
S: * BAD Disk crash, attempting salvage to a new disk! S: * BAD Empty command line
S: * OK Salvage successful, no data lost C: A443 EXPUNGE
S: A443 OK Expunge completed S: * BAD Disk crash, attempting salvage to a new disk!
S: * OK Salvage successful, no data lost
S: A443 OK Expunge completed
7.1.4. PREAUTH Response 7.1.4. PREAUTH Response
Contents: OPTIONAL response code Contents:
OPTIONAL response code
human-readable text human-readable text
The PREAUTH response is always untagged, and is one of three possible The PREAUTH response is always untagged and is one of three possible
greetings at connection startup. It indicates that the connection greetings at connection startup. It indicates that the connection
has already been authenticated by external means; thus no LOGIN/ has already been authenticated by external means; thus, no LOGIN/
AUTHENTICATE command is needed. AUTHENTICATE command is needed.
Because PREAUTH moves the connection directly to the authenticated Because PREAUTH moves the connection directly to the authenticated
state, it effectively prevents the client from using the STARTTLS state, it effectively prevents the client from using the STARTTLS
command Section 6.2.1. For this reason PREAUTH response SHOULD only command (Section 6.2.1). For this reason, the PREAUTH response
be returned by servers on connections that are protected by TLS (such SHOULD only be returned by servers on connections that are protected
as on implicit TLS port [RFC8314]) or protected through other means by TLS (such as on an Implicit TLS port [RFC8314]) or protected
such as IPSec. Clients that require mandatory TLS MUST close the through other means such as IPsec. Clients that require mandatory
connection after receiving PREAUTH response on a non protected port. TLS MUST close the connection after receiving the PREAUTH response on
a non-protected port.
Example: S: * PREAUTH IMAP4rev2 server logged in as Smith Example:
S: * PREAUTH IMAP4rev2 server logged in as Smith
7.1.5. BYE Response 7.1.5. BYE Response
Contents: OPTIONAL response code Contents:
OPTIONAL response code
human-readable text human-readable text
The BYE response is always untagged, and indicates that the server is The BYE response is always untagged and indicates that the server is
about to close the connection. The human-readable text MAY be about to close the connection. The human-readable text MAY be
displayed to the user in a status report by the client. The BYE displayed to the user in a status report by the client. The BYE
response is sent under one of four conditions: response is sent under one of four conditions:
1. as part of a normal logout sequence. The server will close the 1. as part of a normal logout sequence. The server will close the
connection after sending the tagged OK response to the LOGOUT connection after sending the tagged OK response to the LOGOUT
command. command.
2. as a panic shutdown announcement. The server closes the 2. as a panic shutdown announcement. The server closes the
connection immediately. connection immediately.
skipping to change at page 115, line 18 skipping to change at line 5383
3. as an announcement of an inactivity autologout. The server 3. as an announcement of an inactivity autologout. The server
closes the connection immediately. closes the connection immediately.
4. as one of three possible greetings at connection startup, 4. as one of three possible greetings at connection startup,
indicating that the server is not willing to accept a connection indicating that the server is not willing to accept a connection
from this client. The server closes the connection immediately. from this client. The server closes the connection immediately.
The difference between a BYE that occurs as part of a normal LOGOUT The difference between a BYE that occurs as part of a normal LOGOUT
sequence (the first case) and a BYE that occurs because of a failure sequence (the first case) and a BYE that occurs because of a failure
(the other three cases) is that the connection closes immediately in (the other three cases) is that the connection closes immediately in
the failure case. In all cases the client SHOULD continue to read the failure case. In all cases, the client SHOULD continue to read
response data from the server until the connection is closed; this response data from the server until the connection is closed; this
will ensure that any pending untagged or completion responses are will ensure that any pending untagged or completion responses are
read and processed. read and processed.
Example: S: * BYE Autologout; idle for too long Example:
S: * BYE Autologout; idle for too long
7.2. Server Responses - Server Status 7.2. Server Responses - Server Status
These responses are always untagged. This is how server status data These responses are always untagged. This is how server status data
are transmitted from the server to the client. are transmitted from the server to the client.
7.2.1. ENABLED Response 7.2.1. ENABLED Response
Contents: capability listing Contents: capability listing
The ENABLED response occurs as a result of an ENABLE command. The The ENABLED response occurs as a result of an ENABLE command. The
capability listing contains a space-separated listing of capability capability listing contains a space-separated listing of capability
names that the server supports and that were successfully enabled. names that the server supports and that were successfully enabled.
The ENABLED response may contain no capabilities, which means that no The ENABLED response may contain no capabilities, which means that no
extensions listed by the client were successfully enabled. extensions listed by the client were successfully enabled.
Example: S: * ENABLED CONDSTORE QRESYNC Example:
S: * ENABLED CONDSTORE QRESYNC
7.2.2. CAPABILITY Response 7.2.2. CAPABILITY Response
Contents: capability listing Contents: capability listing
The CAPABILITY response occurs as a result of a CAPABILITY command. The CAPABILITY response occurs as a result of a CAPABILITY command.
The capability listing contains a space-separated listing of The capability listing contains a space-separated listing of
capability names that the server supports. The capability listing capability names that the server supports. The capability listing
MUST include the atom "IMAP4rev2", but note that it doesn't have to MUST include the atom "IMAP4rev2", but note that it doesn't have to
be the first capability listed. The order of capability names has no be the first capability listed. The order of capability names has no
significance. significance.
In addition, client and server implementations MUST implement the Client and server implementations MUST implement the capabilities
"STARTTLS" and "LOGINDISABLED" (only on the cleartext port), and "AUTH=PLAIN" (described in [PLAIN]), and MUST implement "STARTTLS"
"AUTH=PLAIN" (described in [PLAIN]) capabilities. See the Security and "LOGINDISABLED" on the cleartext port. See the Security
Considerations (Section 11) for important information related to Considerations (Section 11) for important information related to
these capabilities. these capabilities.
A capability name which begins with "AUTH=" indicates that the server A capability name that begins with "AUTH=" indicates that the server
supports that particular authentication mechanism [SASL]. supports that particular authentication mechanism [SASL].
The LOGINDISABLED capability indicates that the LOGIN command is The LOGINDISABLED capability indicates that the LOGIN command is
disabled, and that the server will respond with a tagged NO response disabled, and that the server will respond with a tagged NO response
to any attempt to use the LOGIN command even if the user name and to any attempt to use the LOGIN command even if the user name and
password are valid. An IMAP client MUST NOT issue the LOGIN command password are valid (their validity will not be checked). An IMAP
if the server advertises the LOGINDISABLED capability. client MUST NOT issue the LOGIN command if the server advertises the
LOGINDISABLED capability.
Other capability names indicate that the server supports an Other capability names indicate that the server supports an
extension, revision, or amendment to the IMAP4rev2 protocol. If extension, revision, or amendment to the IMAP4rev2 protocol. If
IMAP4rev1 capability is not advertised, server responses MUST conform IMAP4rev1 capability is not advertised, server responses MUST conform
to this document until the client issues a command that uses the to this document until the client issues a command that uses an
associated capability. If both IMAP4rev1 and IMAP4rev2 capabilities additional capability. If both IMAP4rev1 and IMAP4rev2 capabilities
are advertised, server responses MUST conform to RFC 3501 until the are advertised, server responses MUST conform to [RFC3501] until the
client issues a command that uses the associated capability. (For client issues a command that uses an additional capability. (For
example, the client can issue ENABLE IMAP4rev2 to enable IMAP4rev2 example, the client can issue ENABLE IMAP4rev2 to enable
specific behaviour). IMAP4rev2-specific behavior.)
Capability names SHOULD be registered with IANA using RFC Required Capability names SHOULD be registered with IANA using the RFC
policy. A server SHOULD NOT offer unregistered capability names. Required policy [RFC8126]. A server SHOULD NOT offer unregistered
capability names.
Client implementations SHOULD NOT require any capability name other Client implementations SHOULD NOT require any capability name other
than "IMAP4rev2", and possibly "STARTTLS" and "LOGINDISABLED" (on a than "IMAP4rev2", and possibly "STARTTLS" and "LOGINDISABLED" (on a
cleartext port). Client implementations MUST ignore any unknown cleartext port). Client implementations MUST ignore any unknown
capability names. capability names.
A server MAY send capabilities automatically, by using the CAPABILITY A server MAY send capabilities automatically, by using the CAPABILITY
response code in the initial PREAUTH or OK responses, and by sending response code in the initial PREAUTH or OK responses and by sending
an updated CAPABILITY response code in the tagged OK response as part an updated CAPABILITY response code in the tagged OK response as part
of a successful authentication. It is unnecessary for a client to of a successful authentication. It is unnecessary for a client to
send a separate CAPABILITY command if it recognizes these automatic send a separate CAPABILITY command if it recognizes these automatic
capabilities and there was no change to the TLS and/or authentication capabilities and there was no change to the TLS and/or authentication
state since they were received. state since they were received.
The list of capabilities returned by a server MAY change during the The list of capabilities returned by a server MAY change during the
connection. In particular, it is quite common for the server to connection. In particular, it is quite common for the server to
change list of capabilities after successful TLS negotiation change the list of capabilities after successful TLS negotiation
(STARTTLS command) and/or after successful authentication (STARTTLS command) and/or after successful authentication
(AUTHENTICATE or LOGIN commands). (AUTHENTICATE or LOGIN commands).
Example: S: * CAPABILITY STARTTLS AUTH=GSSAPI IMAP4rev2 LOGINDISABLED Example:
XPIG-LATIN
Note that in the above example XPIG-LATIN is a fictitious capability S: * CAPABILITY STARTTLS AUTH=GSSAPI IMAP4rev2 LOGINDISABLED
XPIG-LATIN
Note that in the above example, XPIG-LATIN is a fictitious capability
name. name.
7.3. Server Responses - Mailbox Status 7.3. Server Responses - Mailbox Status
These responses are always untagged. This is how mailbox status data These responses are always untagged. This is how mailbox status data
are transmitted from the server to the client. Many of these are transmitted from the server to the client. Many of these
responses typically result from a command with the same name. responses typically result from a command with the same name.
7.3.1. LIST Response 7.3.1. LIST Response
Contents: name attributes Contents:
name attributes
hierarchy delimiter hierarchy delimiter
name name
OPTIONAL extension data OPTIONAL extension data
The LIST response occurs as a result of a LIST command. It returns a The LIST response occurs as a result of a LIST command. It returns a
single name that matches the LIST specification. There can be single name that matches the LIST specification. There can be
multiple LIST responses for a single LIST command. multiple LIST responses for a single LIST command.
The following base mailbox name attributes are defined: The following base mailbox name attributes are defined:
\NonExistent The "\NonExistent" attribute indicates that a mailbox \NonExistent
name does not refer to an existing mailbox. Note that this The "\NonExistent" attribute indicates that a mailbox name does
attribute is not meaningful by itself, as mailbox names that match not refer to an existing mailbox. Note that this attribute is not
the canonical LIST pattern but don't exist must not be returned meaningful by itself, as mailbox names that match the canonical
unless one of the two conditions listed below is also satisfied: LIST pattern but don't exist must not be returned unless one of
the two conditions listed below is also satisfied:
1. The mailbox name also satisfies the selection criteria (for 1. The mailbox name also satisfies the selection criteria (for
example, it is subscribed and the "SUBSCRIBED" selection example, it is subscribed and the "SUBSCRIBED" selection
option has been specified). option has been specified).
2. "RECURSIVEMATCH" has been specified, and the mailbox name has 2. "RECURSIVEMATCH" has been specified, and the mailbox name has
at least one descendant mailbox name that does not match the at least one descendant mailbox name that does not match the
LIST pattern and does match the selection criteria. LIST pattern and does match the selection criteria.
In practice, this means that the "\NonExistent" attribute is In practice, this means that the "\NonExistent" attribute is
usually returned with one or more of "\Subscribed", "\Remote", usually returned with one or more of "\Subscribed", "\Remote",
"\HasChildren", or the CHILDINFO extended data item. "\HasChildren", or the CHILDINFO extended data item.
The "\NonExistent" attribute implies "\NoSelect". The "\NonExistent" attribute implies "\NoSelect".
\Noinferiors It is not possible for any child levels of hierarchy to \Noinferiors
exist under this name; no child levels exist now and none can be It is not possible for any child levels of hierarchy to exist
created in the future. under this name; no child levels exist now and none can be created
in the future.
\Noselect It is not possible to use this name as a selectable \Noselect
mailbox. It is not possible to use this name as a selectable mailbox.
\HasChildren The presence of this attribute indicates that the \HasChildren
mailbox has child mailboxes. A server SHOULD NOT set this The presence of this attribute indicates that the mailbox has
attribute if there are child mailboxes and the user does not have child mailboxes. A server SHOULD NOT set this attribute if there
permission to access any of them. In this case, \HasNoChildren are child mailboxes and the user does not have permission to
SHOULD be used. In many cases, however, a server may not be able access any of them. In this case, \HasNoChildren SHOULD be used.
to efficiently compute whether a user has access to any child In many cases, however, a server may not be able to efficiently
mailbox. Note that even though the \HasChildren attribute for a compute whether a user has access to any child mailboxes. Note
mailbox must be correct at the time of processing of the mailbox, that even though the \HasChildren attribute for a mailbox must be
a client must be prepared to deal with a situation when a mailbox correct at the time of processing the mailbox, a client must be
is marked with the \HasChildren attribute, but no child mailbox prepared to deal with a situation when a mailbox is marked with
appears in the response to the LIST command. This might happen, the \HasChildren attribute, but no child mailbox appears in the
for example, due to children mailboxes being deleted or made response to the LIST command. This might happen, for example, due
inaccessible to the user (using access control) by another client to child mailboxes being deleted or made inaccessible to the user
before the server is able to list them. (using access control) by another client before the server is able
to list them.
\HasNoChildren The presence of this attribute indicates that the \HasNoChildren
mailbox has NO child mailboxes that are accessible to the The presence of this attribute indicates that the mailbox has NO
currently authenticated user. child mailboxes that are accessible to the currently authenticated
user.
\Marked The mailbox has been marked "interesting" by the server; the \Marked
The mailbox has been marked "interesting" by the server; the
mailbox probably contains messages that have been added since the mailbox probably contains messages that have been added since the
last time the mailbox was selected. last time the mailbox was selected.
\Unmarked The mailbox does not contain any additional messages since \Unmarked
the last time the mailbox was selected. The mailbox does not contain any additional messages since the
last time the mailbox was selected.
\Subscribed The mailbox name was subscribed to using the SUBSCRIBE \Subscribed
command. The mailbox name was subscribed to using the SUBSCRIBE command.
\Remote The mailbox is a remote mailbox. \Remote
The mailbox is a remote mailbox.
It is an error for the server to return both a \HasChildren and a It is an error for the server to return both a \HasChildren and a
\HasNoChildren attribute in the same LIST response. A client that \HasNoChildren attribute in the same LIST response. A client that
encounters a LIST response with both \HasChildren and \HasNoChildren encounters a LIST response with both \HasChildren and \HasNoChildren
attributes present should act as if both are absent in the LIST attributes present should act as if both are absent in the LIST
response. response.
Note: the \HasNoChildren attribute should not be confused with the Note: the \HasNoChildren attribute should not be confused with the
\NoInferiors attribute, which indicates that no child mailboxes \NoInferiors attribute, which indicates that no child mailboxes
exist now and none can be created in the future. exist now and none can be created in the future.
If it is not feasible for the server to determine whether or not the If it is not feasible for the server to determine whether or not the
mailbox is "interesting", the server SHOULD NOT send either \Marked mailbox is "interesting", the server SHOULD NOT send either \Marked
or \Unmarked. The server MUST NOT send more than one of \Marked, or \Unmarked. The server MUST NOT send more than one of \Marked,
\Unmarked, and \Noselect for a single mailbox, and MAY send none of \Unmarked, and \Noselect for a single mailbox, and it MAY send none
these. of these.
In addition to the base mailbox name attributes defined above, an In addition to the base mailbox name attributes defined above, an
IMAP server MAY also include any or all of the following attributes IMAP server MAY also include any or all of the following attributes
that denote "role" (or "special-use") of a mailbox. These attributes that denote "role" (or "special-use") of a mailbox. These attributes
are included along with base attributes defined above. A given are included along with base attributes defined above. A given
mailbox may have none, one, or more than one of these attributes. In mailbox may have none, one, or more than one of these attributes. In
some cases, a special use is advice to a client about what to put in some cases, a special use is advice to a client about what to put in
that mailbox. In other cases, it's advice to a client about what to that mailbox. In other cases, it's advice to a client about what to
expect to find there. expect to find there.
\All This mailbox presents all messages in the user's message store. \All
This mailbox presents all messages in the user's message store.
Implementations MAY omit some messages, such as, perhaps, those in Implementations MAY omit some messages, such as, perhaps, those in
\Trash and \Junk. When this special use is supported, it is \Trash and \Junk. When this special use is supported, it is
almost certain to represent a virtual mailbox. almost certain to represent a virtual mailbox.
\Archive This mailbox is used to archive messages. The meaning of \Archive
an "archival" mailbox is server-dependent; typically, it will be This mailbox is used to archive messages. The meaning of an
used to get messages out of the inbox, or otherwise keep them out "archival" mailbox is server dependent; typically, it will be used
of the user's way, while still making them accessible. to get messages out of the inbox, or otherwise keep them out of
the user's way, while still making them accessible.
\Drafts This mailbox is used to hold draft messages -- typically, \Drafts
messages that are being composed but have not yet been sent. In This mailbox is used to hold draft messages -- typically, messages
some server implementations, this might be a virtual mailbox, that are being composed but have not yet been sent. In some
server implementations, this might be a virtual mailbox,
containing messages from other mailboxes that are marked with the containing messages from other mailboxes that are marked with the
"\Draft" message flag. Alternatively, this might just be advice "\Draft" message flag. Alternatively, this might just be advice
that a client put drafts here. that a client put drafts here.
\Flagged This mailbox presents all messages marked in some way as \Flagged
This mailbox presents all messages marked in some way as
"important". When this special use is supported, it is likely to "important". When this special use is supported, it is likely to
represent a virtual mailbox collecting messages (from other represent a virtual mailbox collecting messages (from other
mailboxes) that are marked with the "\Flagged" message flag. mailboxes) that are marked with the "\Flagged" message flag.
\Junk This mailbox is where messages deemed to be junk mail are \Junk
held. Some server implementations might put messages here This mailbox is where messages deemed to be junk mail are held.
automatically. Alternatively, this might just be advice to a Some server implementations might put messages here automatically.
client-side spam filter. Alternatively, this might just be advice to a client-side spam
filter.
\Sent This mailbox is used to hold copies of messages that have been \Sent
This mailbox is used to hold copies of messages that have been
sent. Some server implementations might put messages here sent. Some server implementations might put messages here
automatically. Alternatively, this might just be advice that a automatically. Alternatively, this might just be advice that a
client save sent messages here. client save sent messages here.
\Trash This mailbox is used to hold messages that have been deleted \Trash
or marked for deletion. In some server implementations, this This mailbox is used to hold messages that have been deleted or
might be a virtual mailbox, containing messages from other marked for deletion. In some server implementations, this might
mailboxes that are marked with the "\Deleted" message flag. be a virtual mailbox, containing messages from other mailboxes
that are marked with the "\Deleted" message flag. Alternatively,
Alternatively, this might just be advice that a client that this might just be advice that a client that chooses not to use
chooses not to use the IMAP "\Deleted" model should use this as the IMAP "\Deleted" model should use as its trash location. In
its trash location. In server implementations that strictly server implementations that strictly expect the IMAP "\Deleted"
expect the IMAP "\Deleted" model, this special use is likely not model, this special use is likely not to be supported.
to be supported.
All of special-use attributes are OPTIONAL, and any given server or All special-use attributes are OPTIONAL, and any given server or
message store may support any combination of the attributes, or none message store may support any combination of the attributes, or none
at all. In most cases, there will likely be at most one mailbox with at all. In most cases, there will likely be at most one mailbox with
a given attribute for a given user, but in some server or message a given attribute for a given user, but in some server or message
store implementations it might be possible for multiple mailboxes to store implementations, it might be possible for multiple mailboxes to
have the same special-use attribute. have the same special-use attribute.
Special-use attributes are likely to be user-specific. User Adam Special-use attributes are likely to be user specific. User Adam
might share his \Sent mailbox with user Barb, but that mailbox is might share his \Sent mailbox with user Barb, but that mailbox is
unlikely to also serve as Barb's \Sent mailbox. unlikely to also serve as Barb's \Sent mailbox.
Other mailbox name attributes can be found in the "IMAP Mailbox Name Other mailbox name attributes can be found in the "IMAP Mailbox Name
Attributes" registry [IMAP-MAILBOX-NAME-ATTRS-REG]. Attributes" registry [IMAP-MAILBOX-NAME-ATTRS-REG].
The hierarchy delimiter is a character used to delimit levels of The hierarchy delimiter is a character used to delimit levels of
hierarchy in a mailbox name. A client can use it to create child hierarchy in a mailbox name. A client can use it to create child
mailboxes, and to search higher or lower levels of naming hierarchy. mailboxes and to search higher or lower levels of naming hierarchy.
All children of a top-level hierarchy node MUST use the same All children of a top-level hierarchy node MUST use the same
separator character. A NIL hierarchy delimiter means that no separator character. A NIL hierarchy delimiter means that no
hierarchy exists; the name is a "flat" name. hierarchy exists; the name is a "flat" name.
The name represents an unambiguous left-to-right hierarchy, and MUST The name represents an unambiguous left-to-right hierarchy and MUST
be valid for use as a reference in LIST command. Unless \Noselect or be valid for use as a reference in LIST command. Unless \Noselect or
\NonExistent is indicated, the name MUST also be valid as an argument \NonExistent is indicated, the name MUST also be valid as an argument
for commands, such as SELECT, that accept mailbox names. for commands, such as SELECT, that accept mailbox names.
The name might be followed by an OPTIONAL series of extended fields, The name might be followed by an OPTIONAL series of extended fields,
a parenthesized list of tagged data (also referred to as "extended a parenthesized list of tagged data (also referred to as an "extended
data item"). The first element of an extended field is a string, data item"). The first element of an extended field is a string,
which identifies the type of data. [RFC5258] specified requirements which identifies the type of data. [RFC5258] specifies requirements
on string registration (which are called "tags" there; such tags are on string registration (which are called "tags"; such tags are not to
not to be confused with IMAP command tags), in particular it said be confused with IMAP command tags); in particular, it states that
that "Tags MUST be registered with IANA". This document doesn't "Tags MUST be registered with IANA". This document doesn't change
change that. See Section 9.5 of [RFC5258] for the registration that. See Section 9.5 of [RFC5258] for the registration template.
template. The server MAY return data in the extended fields that was The server MAY return data in the extended fields that was not
not directly solicited by the client in the corresponding LIST directly solicited by the client in the corresponding LIST command.
command. For example, the client can enable extra extended fields by For example, the client can enable extra extended fields by using
using another IMAP extension that make use of the extended LIST another IMAP extension that makes use of the extended LIST responses.
responses. The client MUST ignore all extended fields it doesn't The client MUST ignore all extended fields it doesn't recognize.
recognize.
Example: S: * LIST (\Noselect) "/" ~/Mail/foo Example:
Example: S: * LIST (\Marked) ":" Tables (tablecloth (("edge" "lacy") S: * LIST (\Noselect) "/" ~/Mail/foo
("color" "red")) Sample "text")
S: * LIST () ":" Tables:new (tablecloth ("edge" "lacy") Example:
Sample ("text" "more text"))
S: * LIST (\Marked) ":" Tables (tablecloth (("edge" "lacy")
("color" "red")) Sample "text")
S: * LIST () ":" Tables:new (tablecloth ("edge" "lacy")
Sample ("text" "more text"))
7.3.2. NAMESPACE Response 7.3.2. NAMESPACE Response
Contents: the prefix and hierarchy delimiter to the server's Contents: the prefix and hierarchy delimiter to the server's
Personal Namespace(s), Other Users' Namespace(s), and Personal Namespace(s), Other Users' Namespace(s), and
Shared Namespace(s) Shared Namespace(s)
The NAMESPACE response occurs as a result of a NAMESPACE command. It The NAMESPACE response occurs as a result of a NAMESPACE command. It
contains the prefix and hierarchy delimiter to the server's Personal contains the prefix and hierarchy delimiter to the server's Personal
Namespace(s), Other Users' Namespace(s), and Shared Namespace(s) that Namespace(s), Other Users' Namespace(s), and Shared Namespace(s) that
the server wishes to expose. The response will contain a NIL for any the server wishes to expose. The response will contain a NIL for any
namespace class that is not available. Namespace-Response-Extensions namespace class that is not available. The Namespace-Response-
ABNF non terminal is defined for extensibility and MAY be included in Extensions ABNF non-terminal is defined for extensibility and MAY be
the response. included in the response.
Example: S: * NAMESPACE (("" "/")) (("~" "/")) NIL Example:
S: * NAMESPACE (("" "/")) (("~" "/")) NIL
7.3.3. STATUS Response 7.3.3. STATUS Response
Contents: name Contents:
name
status parenthesized list status parenthesized list
The STATUS response occurs as a result of an STATUS command. It The STATUS response occurs as a result of a STATUS command. It
returns the mailbox name that matches the STATUS specification and returns the mailbox name that matches the STATUS specification and
the requested mailbox status information. the requested mailbox status information.
Example: S: * STATUS blurdybloop (MESSAGES 231 UIDNEXT 44292) Example:
S: * STATUS blurdybloop (MESSAGES 231 UIDNEXT 44292)
7.3.4. ESEARCH Response 7.3.4. ESEARCH Response
Contents: one or more search-return-data pairs Contents: one or more search-return-data pairs
The ESEARCH response occurs as a result of a SEARCH or UID SEARCH The ESEARCH response occurs as a result of a SEARCH or UID SEARCH
command. command.
The ESEARCH response starts with an optional search correlator. If The ESEARCH response starts with an optional search correlator. If
it is missing, then the response was not caused by a particular IMAP it is missing, then the response was not caused by a particular IMAP
command, whereas if it is present, it contains the tag of the command command, whereas if it is present, it contains the tag of the command
that caused the response to be returned. that caused the response to be returned.
The search correlator is followed by an optional UID indicator. If The search correlator is followed by an optional UID indicator. If
this indicator is present, all data in the ESEARCH response refers to this indicator is present, all data in the ESEARCH response refers to
UIDs, otherwise all returned data refers to message numbers. UIDs; otherwise, all returned data refers to message numbers.
The rest of the ESEARCH response contains one or more search data The rest of the ESEARCH response contains one or more search data
pairs. Each pair starts with unique return item name, followed by a pairs. Each pair starts with a unique return item name, followed by
space and the corresponding data. Search data pairs may be returned a space and the corresponding data. Search data pairs may be
in any order. Unless specified otherwise by an extension, any return returned in any order. Unless otherwise specified by an extension,
item name SHOULD appear only once in an ESEARCH response. any return item name SHOULD appear only once in an ESEARCH response.
This document specifies the following return item names: This document specifies the following return item names:
MIN MIN
Returns the lowest message number/UID that satisfies the SEARCH
criteria.
Returns the lowest message number/UID that satisfies the SEARCH If the SEARCH results in no matches, the server MUST NOT include
criteria. the MIN return item in the ESEARCH response; however, it still
MUST send the ESEARCH response.
If the SEARCH results in no matches, the server MUST NOT
include the MIN return item in the ESEARCH response; however,
it still MUST send the ESEARCH response.
MAX MAX
Returns the highest message number/UID that satisfies the SEARCH
criteria.
Returns the highest message number/UID that satisfies the If the SEARCH results in no matches, the server MUST NOT include
SEARCH criteria. the MAX return item in the ESEARCH response; however, it still
MUST send the ESEARCH response.
If the SEARCH results in no matches, the server MUST NOT
include the MAX return item in the ESEARCH response; however,
it still MUST send the ESEARCH response.
ALL ALL
Returns all message numbers/UIDs that satisfy the SEARCH criteria
using the sequence-set syntax. Each set MUST be complete; in
particular, a UID set is returned in an ESEARCH response only when
each number in the range corresponds to an existing (matching)
message. The client MUST NOT assume that messages/UIDs will be
listed in any particular order.
Returns all message numbers/UIDs that satisfy the SEARCH If the SEARCH results in no matches, the server MUST NOT include
criteria using the sequence-set syntax. Note, the client MUST the ALL return item in the ESEARCH response; however, it still
NOT assume that messages/UIDs will be listed in any particular MUST send the ESEARCH response.
order.
If the SEARCH results in no matches, the server MUST NOT COUNT
include the ALL return item in the ESEARCH response; however, Returns the number of messages that satisfy the SEARCH criteria.
it still MUST send the ESEARCH response. This return item MUST always be included in the ESEARCH response.
COUNT Returns the number of messages that satisfy the SEARCH Example:
criteria. This return item MUST always be included in the ESEARCH
response.
Example: S: * ESEARCH UID COUNT 5 ALL 4:19,21,28 S: * ESEARCH UID COUNT 17 ALL 4:18,21,28
Example: S: * ESEARCH (TAG "a567") UID COUNT 5 ALL 4:19,21,28 Example:
Example: S: * ESEARCH COUNT 5 ALL 1:17,21 S: * ESEARCH (TAG "a567") UID COUNT 17 ALL 4:18,21,28
Example:
S: * ESEARCH COUNT 18 ALL 1:17,21
7.3.5. FLAGS Response 7.3.5. FLAGS Response
Contents: flag parenthesized list Contents: flag parenthesized list
The FLAGS response occurs as a result of a SELECT or EXAMINE command. The FLAGS response occurs as a result of a SELECT or EXAMINE command.
The flag parenthesized list identifies the flags (at a minimum, the The flag parenthesized list identifies the flags (at a minimum, the
system-defined flags) that are applicable for this mailbox. Flags system-defined flags) that are applicable for this mailbox. Flags
other than the system flags can also exist, depending on server other than the system flags can also exist, depending on server
implementation. implementation.
The update from the FLAGS response MUST be remembered by the client. The update from the FLAGS response MUST be remembered by the client.
Example: S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft) Example:
S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
7.4. Server Responses - Mailbox Size 7.4. Server Responses - Mailbox Size
These responses are always untagged. This is how changes in the size These responses are always untagged. This is how changes in the size
of the mailbox are transmitted from the server to the client. of the mailbox are transmitted from the server to the client.
Immediately following the "*" token is a number that represents a Immediately following the "*" token is a number that represents a
message count. message count.
7.4.1. EXISTS Response 7.4.1. EXISTS Response
Contents: none Contents: none
The EXISTS response reports the number of messages in the mailbox. The EXISTS response reports the number of messages in the mailbox.
This response occurs as a result of a SELECT or EXAMINE command, and This response occurs as a result of a SELECT or EXAMINE command and
if the size of the mailbox changes (e.g., new messages). if the size of the mailbox changes (e.g., new messages).
The update from the EXISTS response MUST be remembered by the client. The update from the EXISTS response MUST be remembered by the client.
Example: S: * 23 EXISTS Example:
S: * 23 EXISTS
7.5. Server Responses - Message Status 7.5. Server Responses - Message Status
These responses are always untagged. This is how message data are These responses are always untagged. This is how message data are
transmitted from the server to the client, often as a result of a transmitted from the server to the client, often as a result of a
command with the same name. Immediately following the "*" token is a command with the same name. Immediately following the "*" token is a
number that represents a message sequence number. number that represents a message sequence number.
7.5.1. EXPUNGE Response 7.5.1. EXPUNGE Response
skipping to change at page 124, line 17 skipping to change at line 5853
The EXPUNGE response also decrements the number of messages in the The EXPUNGE response also decrements the number of messages in the
mailbox; it is not necessary to send an EXISTS response with the new mailbox; it is not necessary to send an EXISTS response with the new
value. value.
As a result of the immediate decrement rule, message sequence numbers As a result of the immediate decrement rule, message sequence numbers
that appear in a set of successive EXPUNGE responses depend upon that appear in a set of successive EXPUNGE responses depend upon
whether the messages are removed starting from lower numbers to whether the messages are removed starting from lower numbers to
higher numbers, or from higher numbers to lower numbers. For higher numbers, or from higher numbers to lower numbers. For
example, if the last 5 messages in a 9-message mailbox are expunged, example, if the last 5 messages in a 9-message mailbox are expunged,
a "lower to higher" server will send five untagged EXPUNGE responses a "lower to higher" server will send five untagged EXPUNGE responses
for message sequence number 5, whereas a "higher to lower server" for message sequence number 5, whereas a "higher to lower" server
will send successive untagged EXPUNGE responses for message sequence will send successive untagged EXPUNGE responses for message sequence
numbers 9, 8, 7, 6, and 5. numbers 9, 8, 7, 6, and 5.
An EXPUNGE response MUST NOT be sent when no command is in progress, An EXPUNGE response MUST NOT be sent when no command is in progress,
nor while responding to a FETCH, STORE, or SEARCH command. This rule nor while responding to a FETCH, STORE, or SEARCH command. This rule
is necessary to prevent a loss of synchronization of message sequence is necessary to prevent a loss of synchronization of message sequence
numbers between client and server. A command is not "in progress" numbers between client and server. A command is not "in progress"
until the complete command has been received; in particular, a until the complete command has been received; in particular, a
command is not "in progress" during the negotiation of command command is not "in progress" during the negotiation of command
continuation. continuation.
Note: UID FETCH, UID STORE, and UID SEARCH are different commands Note: UID FETCH, UID STORE, and UID SEARCH are different commands
from FETCH, STORE, and SEARCH. An EXPUNGE response MAY be sent from FETCH, STORE, and SEARCH. An EXPUNGE response MAY be sent
during a UID command. during a UID command.
The update from the EXPUNGE response MUST be remembered by the The update from the EXPUNGE response MUST be remembered by the
client. client.
Example: S: * 44 EXPUNGE Example:
S: * 44 EXPUNGE
7.5.2. FETCH Response 7.5.2. FETCH Response
Contents: message data Contents: message data
The FETCH response returns data about a message to the client. The The FETCH response returns data about a message to the client. The
data are pairs of data item names and their values in parentheses. data are pairs of data item names, and their values are in
This response occurs as the result of a FETCH or STORE command, as parentheses. This response occurs as the result of a FETCH or STORE
well as by unilateral server decision (e.g., flag updates). command, as well as by a unilateral server decision (e.g., flag
updates).
The current data items are: The current data items are:
BINARY[<section-binary>]<<number>> BINARY[<section-binary>]<<number>>
An <nstring> or <literal8> expressing the content of the An <nstring> or <literal8> expressing the content of the specified
specified section after removing any Content-Transfer-Encoding- section after removing any encoding specified in the corresponding
related encoding. If <number> is present it refers to the Content-Transfer-Encoding header field. If <number> is present,
offset within the DECODED section data. it refers to the offset within the DECODED section data.
If the domain of the decoded data is "8bit" and the data does If the domain of the decoded data is "8bit" and the data does not
not contain the NUL octet, the server SHOULD return the data in contain the NUL octet, the server SHOULD return the data in a
a <string> instead of a <literal8>; this allows the client to <string> instead of a <literal8>; this allows the client to
determine if the "8bit" data contains the NUL octet without determine if the "8bit" data contains the NUL octet without having
having to explicitly scan the data stream for for NULs. to explicitly scan the data stream for NULs.
Messaging clients and servers have been notoriously lax in Messaging clients and servers have been notoriously lax in their
their adherence to the Internet CRLF convention for terminating adherence to the Internet CRLF convention for terminating lines of
lines of textual data (text/* media types) in Internet textual data (text/* media types) in Internet protocols. When
protocols. When sending data in BINARY[...] FETCH data item, sending data in a BINARY[...] FETCH data item, servers MUST ensure
servers MUST ensure that textual line-oriented sections are that textual line-oriented sections are always transmitted using
always transmitted using the IMAP4 CRLF line termination the IMAP CRLF line termination syntax, regardless of the
syntax, regardless of the underlying storage representation of underlying storage representation of the data on the server.
the data on the server.
If the server does not know how to decode the section's If the server does not know how to decode the section's Content-
Content-Transfer-Encoding, it MUST fail the request and issue a Transfer-Encoding, it MUST fail the request and issue a "NO"
"NO" response that contains the "UNKNOWN-CTE" response code. response that contains the "UNKNOWN-CTE" response code.
BINARY.SIZE[<section-binary>] BINARY.SIZE[<section-binary>]
The size of the section after removing any encoding specified in
the corresponding Content-Transfer-Encoding header field. The
value returned MUST match the size of the <nstring> or <literal8>
that will be returned by the corresponding FETCH BINARY request.
The size of the section after removing any Content-Transfer- If the server does not know how to decode the section's Content-
Encoding-related encoding. The value returned MUST match the Transfer-Encoding, it MUST fail the request and issue a "NO"
size of the <nstring> or <literal8> that will be returned by response that contains the "UNKNOWN-CTE" response code.
the corresponding FETCH BINARY request.
If the server does not know how to decode the section's
Content-Transfer-Encoding, it MUST fail the request and issue a
"NO" response that contains the "UNKNOWN-CTE" response code.
BODY A form of BODYSTRUCTURE without extension data. BODY
A form of BODYSTRUCTURE without extension data.
BODY[<section>]<<origin octet>> BODY[<section>]<<origin octet>>
A string expressing the body contents of the specified section.
The string SHOULD be interpreted by the client according to the
content transfer encoding, body type, and subtype.
A string expressing the body contents of the specified section. If the origin octet is specified, this string is a substring of
The string SHOULD be interpreted by the client according to the the entire body contents, starting at that origin octet. This
content transfer encoding, body type, and subtype. means that BODY[]<0> MAY be truncated, but BODY[] is NEVER
truncated.
If the origin octet is specified, this string is a substring of
the entire body contents, starting at that origin octet. This
means that BODY[]<0> MAY be truncated, but BODY[] is NEVER
truncated.
Note: The origin octet facility MUST NOT be used by a server Note: The origin octet facility MUST NOT be used by a server in
in a FETCH response unless the client specifically requested a FETCH response unless the client specifically requested it by
it by means of a FETCH of a BODY[<section>]<<partial>> data means of a FETCH of a BODY[<section>]<<partial>> data item.
item.
8-bit textual data is permitted if a [CHARSET] identifier is 8-bit textual data is permitted if a [CHARSET] identifier is part
part of the body parameter parenthesized list for this section. of the body parameter parenthesized list for this section. Note
Note that headers (part specifiers HEADER or MIME, or the that headers (part specifiers HEADER or MIME, or the header
header portion of a MESSAGE/RFC822 or MESSAGE/GLOBAL part), MAY portion of a MESSAGE/RFC822 or MESSAGE/GLOBAL part) MAY be in UTF-
be in UTF-8. Note also that the [RFC-5322] delimiting blank 8. Note also that the [RFC5322] delimiting blank line between the
line between the header and the body is not affected by header header and the body is not affected by header-line subsetting; the
line subsetting; the blank line is always included as part of blank line is always included as part of the header data, except
header data, except in the case of a message which has no body in the case of a message that has no body and no blank line.
and no blank line.
Non-textual data such as binary data MUST be transfer encoded Non-textual data such as binary data MUST be transfer encoded into
into a textual form, such as BASE64, prior to being sent to the a textual form, such as base64, prior to being sent to the client.
client. To derive the original binary data, the client MUST To derive the original binary data, the client MUST decode the
decode the transfer encoded string. transfer-encoded string.
BODYSTRUCTURE BODYSTRUCTURE
A parenthesized list that describes the [MIME-IMB] body structure
of a message. This is computed by the server by parsing the
[MIME-IMB] header fields, defaulting various fields as necessary.
A parenthesized list that describes the [MIME-IMB] body For example, a simple text message of 48 lines and 2279 octets can
structure of a message. This is computed by the server by have a body structure of:
parsing the [MIME-IMB] header fields, defaulting various fields
as necessary.
For example, a simple text message of 48 lines and 2279 octets ("TEXT" "PLAIN" ("CHARSET" "US-ASCII") NIL NIL "7BIT" 2279 48)
can have a body structure of: ("TEXT" "PLAIN" ("CHARSET" "US-
ASCII") NIL NIL "7BIT" 2279 48)
Multiple parts are indicated by parenthesis nesting. Instead Multiple parts are indicated by parenthesis nesting. Instead of a
of a body type as the first element of the parenthesized list, body type as the first element of the parenthesized list, there is
there is a sequence of one or more nested body structures. The a sequence of one or more nested body structures. The second
second element of the parenthesized list is the multipart element of the parenthesized list is the multipart subtype (mixed,
subtype (mixed, digest, parallel, alternative, etc.). digest, parallel, alternative, etc.).
For example, a two part message consisting of a text and a For example, a two-part message consisting of a text and a
BASE64-encoded text attachment can have a body structure of: base64-encoded text attachment can have a body structure of:
(("TEXT" "PLAIN" ("CHARSET" "US-ASCII") NIL NIL "7BIT" 1152
23)("TEXT" "PLAIN" ("CHARSET" "US-ASCII" "NAME" "cc.diff")
"<960723163407.20117h@cac.washington.edu>" "Compiler diff"
"BASE64" 4554 73) "MIXED")
Extension data follows the multipart subtype. Extension data (("TEXT" "PLAIN" ("CHARSET" "US-ASCII") NIL NIL "7BIT" 1152 23)
is never returned with the BODY fetch, but can be returned with ("TEXT" "PLAIN" ("CHARSET" "US-ASCII" "NAME" "cc.diff")
a BODYSTRUCTURE fetch. Extension data, if present, MUST be in "<960723163407.20117h@cac.washington.edu>" "Compiler diff"
the defined order. The extension data of a multipart body part "BASE64" 4554 73) "MIXED")
are in the following order:
body parameter parenthesized list A parenthesized list of Extension data follows the multipart subtype. Extension data is
attribute/value pairs [e.g., ("foo" "bar" "baz" "rag") where never returned with the BODY fetch but can be returned with a
"bar" is the value of "foo", and "rag" is the value of BODYSTRUCTURE fetch. Extension data, if present, MUST be in the
"baz"] as defined in [MIME-IMB]. Servers SHOULD decode defined order. The extension data of a multipart body part are in
parameter value continuations and parameter value character the following order:
sets as described in [RFC2231], for example, if the message
contains parameters "baz*0", "baz*1" and "baz*2", the server
should RFC2231-decode them, concatenate and return the
resulting value as a parameter "baz". Similarly, if the
message contains parameters "foo*0*" and "foo*1*", the
server should RFC2231-decode them, convert to UTF-8,
concatenate and return the resulting value as a parameter
"foo*".
body disposition A parenthesized list, consisting of a body parameter parenthesized list
disposition type string, followed by a parenthesized list of A parenthesized list of attribute/value pairs (e.g., ("foo" "bar"
disposition attribute/value pairs as defined in "baz" "rag") where "bar" is the value of "foo", and "rag" is the
[DISPOSITION]. Servers SHOULD decode parameter value value of "baz") as defined in [MIME-IMB]. Servers SHOULD decode
continuations as described in [RFC2231]. parameter-value continuations and parameter-value character sets
as described in [RFC2231], for example, if the message contains
parameters "baz*0", "baz*1", and "baz*2", the server should decode
them per [RFC2231], concatenate, and return the resulting value as
a parameter "baz". Similarly, if the message contains parameters
"foo*0*" and "foo*1*", the server should decode them per
[RFC2231], convert to UTF-8, concatenate, and return the resulting
value as a parameter "foo*".
body language A string or parenthesized list giving the body body disposition
language value as defined in [LANGUAGE-TAGS]. A parenthesized list, consisting of a disposition type string,
followed by a parenthesized list of disposition attribute/value
pairs as defined in [DISPOSITION]. Servers SHOULD decode
parameter-value continuations as described in [RFC2231].
body location A string giving the body content URI as defined body language
in [LOCATION]. A string or parenthesized list giving the body language value as
defined in [LANGUAGE-TAGS].
Any following extension data are not yet defined in this body location
version of the protocol. Such extension data can consist of A string giving the body content URI as defined in [LOCATION].
zero or more NILs, strings, numbers, or potentially nested
parenthesized lists of such data. Client implementations that
do a BODYSTRUCTURE fetch MUST be prepared to accept such
extension data. Server implementations MUST NOT send such
extension data until it has been defined by a revision of this
protocol.
The basic fields of a non-multipart body part are in the Any following extension data are not yet defined in this version
following order: of the protocol. Such extension data can consist of zero or more
NILs, strings, numbers, or potentially nested parenthesized lists
of such data. Client implementations that do a BODYSTRUCTURE
fetch MUST be prepared to accept such extension data. Server
implementations MUST NOT send such extension data until it has
been defined by a revision of this protocol.
body type A string giving the content media type name as The basic fields of a non-multipart body part are in the following
defined in [MIME-IMB]. order:
body subtype A string giving the content subtype name as body type
defined in [MIME-IMB]. A string giving the content media-type name as defined in
[MIME-IMB].
body parameter parenthesized list A parenthesized list of body subtype
attribute/value pairs [e.g., ("foo" "bar" "baz" "rag") where A string giving the content subtype name as defined in [MIME-IMB].
"bar" is the value of "foo" and "rag" is the value of "baz"]
as defined in [MIME-IMB].
body id A string giving the Content-ID header field value as body parameter parenthesized list
defined in Section 7 of [MIME-IMB]. A parenthesized list of attribute/value pairs (e.g., ("foo" "bar"
"baz" "rag") where "bar" is the value of "foo", and "rag" is the
value of "baz") as defined in [MIME-IMB].
body description A string giving the Content-Description body id
header field value as defined in Section 8 of [MIME-IMB]. A string giving the Content-ID header field value as defined in
Section 7 of [MIME-IMB].
body encoding A string giving the content transfer encoding as body description
defined in Section 6 of [MIME-IMB]. A string giving the Content-Description header field value as
defined in Section 8 of [MIME-IMB].
body size A number giving the size of the body in octets. body encoding
Note that this size is the size in its transfer encoding and A string giving the content transfer encoding as defined in
not the resulting size after any decoding. Section 6 of [MIME-IMB].
A body type of type MESSAGE and subtype RFC822 contains, body size
immediately after the basic fields, the envelope structure, A number giving the size of the body in octets. Note that this
body structure, and size in text lines of the encapsulated size is the size in its transfer encoding and not the resulting
message. size after any decoding.
A body type of type TEXT contains, immediately after the basic A body type of type MESSAGE and subtype RFC822 contains,
fields, the size of the body in text lines. Note that this immediately after the basic fields, the envelope structure, body
size is the size in its content transfer encoding and not the structure, and size in text lines of the encapsulated message.
resulting size after any decoding.
Extension data follows the basic fields and the type-specific A body type of type TEXT contains, immediately after the basic
fields listed above. Extension data is never returned with the fields, the size of the body in text lines. Note that this size
BODY fetch, but can be returned with a BODYSTRUCTURE fetch. is the size in its content transfer encoding and not the resulting
Extension data, if present, MUST be in the defined order. size after any decoding.
The extension data of a non-multipart body part are in the Extension data follows the basic fields and the type-specific
following order: fields listed above. Extension data is never returned with the
BODY fetch but can be returned with a BODYSTRUCTURE fetch.
Extension data, if present, MUST be in the defined order.
body MD5 A string giving the body MD5 value as defined in The extension data of a non-multipart body part are in the
[MD5]. following order:
body disposition A parenthesized list with the same content body MD5
and function as the body disposition for a multipart body A string giving the body MD5 value as defined in [MD5].
part.
body language A string or parenthesized list giving the body body disposition
language value as defined in [LANGUAGE-TAGS]. A parenthesized list with the same content and function as the
body disposition for a multipart body part.
body location A string giving the body content URI as defined body language
in [LOCATION]. A string or parenthesized list giving the body language value as
defined in [LANGUAGE-TAGS].
Any following extension data are not yet defined in this body location
version of the protocol, and would be as described above under A string giving the body content URI as defined in [LOCATION].
multipart extension data.
ENVELOPE Any following extension data are not yet defined in this version
of the protocol and would be as described above under multipart
extension data.
A parenthesized list that describes the envelope structure of a ENVELOPE
message. This is computed by the server by parsing the A parenthesized list that describes the envelope structure of a
[RFC-5322] header into the component parts, defaulting various message. This is computed by the server by parsing the [RFC5322]
fields as necessary. header into the component parts, defaulting various fields as
necessary.
The fields of the envelope structure are in the following The fields of the envelope structure are in the following order:
order: date, subject, from, sender, reply-to, to, cc, bcc, in- date, subject, from, sender, reply-to, to, cc, bcc, in-reply-to,
reply-to, and message-id. The date, subject, in-reply-to, and and message-id. The date, subject, in-reply-to, and message-id
message-id fields are strings. The from, sender, reply-to, to, fields are strings. The from, sender, reply-to, to, cc, and bcc
cc, and bcc fields are parenthesized lists of address fields are parenthesized lists of address structures.
structures.
An address structure is a parenthesized list that describes an An address structure is a parenthesized list that describes an
electronic mail address. The fields of an address structure electronic mail address. The fields of an address structure are
are in the following order: display name, [SMTP] at-domain-list in the following order: display name, [SMTP] at-domain-list
(source route, obs-route ABNF production from [RFC-5322]), (source route and obs-route ABNF production from [RFC5322]),
mailbox name (local-part ABNF production from [RFC-5322]), and mailbox name (local-part ABNF production from [RFC5322]), and
host name. hostname.
[RFC-5322] group syntax is indicated by a special form of [RFC5322] group syntax is indicated by a special form of address
address structure in which the host name field is NIL. If the structure in which the hostname field is NIL. If the mailbox name
mailbox name field is also NIL, this is an end of group marker field is also NIL, this is an end-of-group marker (semicolon in
(semi-colon in RFC 822 syntax). If the mailbox name field is RFC 822 syntax). If the mailbox name field is non-NIL, this is
non-NIL, this is a start of group marker, and the mailbox name the start of a group marker, and the mailbox name field holds the
field holds the group name phrase. group name phrase.
If the Date, Subject, In-Reply-To, and Message-ID header fields If the Date, Subject, In-Reply-To, and Message-ID header fields
are absent in the [RFC-5322] header, the corresponding member are absent in the [RFC5322] header, the corresponding member of
of the envelope is NIL; if these header fields are present but the envelope is NIL; if these header fields are present but empty,
empty the corresponding member of the envelope is the empty the corresponding member of the envelope is the empty string.
string.
Note: some servers may return a NIL envelope member in the Note: some servers may return a NIL envelope member in the
"present but empty" case. Clients SHOULD treat NIL and "present but empty" case. Clients SHOULD treat NIL and the
empty string as identical. empty string as identical.
Note: [RFC-5322] requires that all messages have a valid Note: [RFC5322] requires that all messages have a valid Date
Date header field. Therefore, for a well-formed message the header field. Therefore, for a well-formed message, the date
date member in the envelope can not be NIL or the empty member in the envelope cannot be NIL or the empty string.
string. However it can be NIL for a malformed or a draft However, it can be NIL for a malformed or draft message.
message.
Note: [RFC-5322] requires that the In-Reply-To and Message- Note: [RFC5322] requires that the In-Reply-To and Message-ID
ID header fields, if present, have non-empty content. header fields, if present, have non-empty content. Therefore,
Therefore, for a well-formed message the in-reply-to and for a well-formed message, the in-reply-to and message-id
message-id members in the envelope can not be the empty members in the envelope cannot be the empty string. However,
string. However they can still be the empty string for a they can still be the empty string for a malformed message.
malformed message.
If the From, To, Cc, and Bcc header fields are absent in the If the From, To, Cc, and Bcc header fields are absent in the
[RFC-5322] header, or are present but empty, the corresponding [RFC5322] header, or are present but empty, the corresponding
member of the envelope is NIL. member of the envelope is NIL.
If the Sender or Reply-To header fields are absent in the If the Sender or Reply-To header fields are absent in the
[RFC-5322] header, or are present but empty, the server sets [RFC5322] header, or are present but empty, the server sets the
the corresponding member of the envelope to be the same value corresponding member of the envelope to be the same value as the
as the from member (the client is not expected to know to do from member (the client is not expected to know how to do this).
this).
Note: [RFC-5322] requires that all messages have a valid Note: [RFC5322] requires that all messages have a valid From
From header field. Therefore, for a well-formed message the header field. Therefore, for a well-formed message, the from,
from, sender, and reply-to members in the envelope can not sender, and reply-to members in the envelope cannot be NIL.
be NIL. However they can be NIL for a malformed or a draft However, they can be NIL for a malformed or draft message.
message.
FLAGS A parenthesized list of flags that are set for this message. FLAGS
A parenthesized list of flags that are set for this message.
INTERNALDATE A string representing the internal date of the message. INTERNALDATE
A string representing the internal date of the message.
RFC822.SIZE A number expressing the [RFC-5322] size of the message. RFC822.SIZE
A number expressing the size of a message, as described in
Section 2.3.4.
UID A number expressing the unique identifier of the message. UID
A number expressing the unique identifier of the message.
If the server chooses to send unsolicited FETCH responses, they MUST If the server chooses to send unsolicited FETCH responses, they MUST
include UID FETCH item. Note that this is a new requirement when include UID FETCH item. Note that this is a new requirement when
compared to RFC 3501. compared to [RFC3501].
Example: S: * 23 FETCH (FLAGS (\Seen) RFC822.SIZE 44827 UID 447) Example:
S: * 23 FETCH (FLAGS (\Seen) RFC822.SIZE 44827 UID 447)
7.6. Server Responses - Command Continuation Request 7.6. Server Responses - Command Continuation Request
The command continuation request response is indicated by a "+" token The command continuation request response is indicated by a "+" token
instead of a tag. This form of response indicates that the server is instead of a tag. This form of response indicates that the server is
ready to accept the continuation of a command from the client. The ready to accept the continuation of a command from the client. The
remainder of this response is a line of text. remainder of this response is a line of text.
This response is used in the AUTHENTICATE command to transmit server This response is used in the AUTHENTICATE command to transmit server
data to the client, and request additional client data. This data to the client and request additional client data. This response
response is also used if an argument to any command is a is also used if an argument to any command is a synchronizing
synchronizing literal. literal.
The client is not permitted to send the octets of the synchronizing The client is not permitted to send the octets of the synchronizing
literal unless the server indicates that it is expected. This literal unless the server indicates that it is expected. This
permits the server to process commands and reject errors on a line- permits the server to process commands and reject errors on a line-
by-line basis. The remainder of the command, including the CRLF that by-line basis. The remainder of the command, including the CRLF that
terminates a command, follows the octets of the literal. If there terminates a command, follows the octets of the literal. If there
are any additional command arguments, the literal octets are followed are any additional command arguments, the literal octets are followed
by a space and those arguments. by a space and those arguments.
Example: C: A001 LOGIN {11} Example:
S: + Ready for additional command text
C: FRED FOOBAR {7}
S: + Ready for additional command text
C: fat man
S: A001 OK LOGIN completed
C: A044 BLURDYBLOOP {102856}
S: A044 BAD No such command as "BLURDYBLOOP"
8. Sample IMAP4rev2 connection C: A001 LOGIN {11}
S: + Ready for additional command text
C: FRED FOOBAR {7}
S: + Ready for additional command text
C: fat man
S: A001 OK LOGIN completed
C: A044 BLURDYBLOOP {102856}
S: A044 BAD No such command as "BLURDYBLOOP"
The following is a transcript of an IMAP4rev2 connection on a non TLS 8. Sample IMAP4rev2 Connection
The following is a transcript of an IMAP4rev2 connection on a non-TLS
port. A long line in this sample is broken for editorial clarity. port. A long line in this sample is broken for editorial clarity.
S: * OK [CAPABILITY STARTTLS AUTH=SCRAM-SHA-256 LOGINDISABLED S: * OK [CAPABILITY STARTTLS AUTH=SCRAM-SHA-256 LOGINDISABLED
IMAP4rev2] IMAP4rev2 Service Ready IMAP4rev2] IMAP4rev2 Service Ready
C: a000 starttls C: a000 starttls
S: a000 OK Proceed with TLS negotiation S: a000 OK Proceed with TLS negotiation
<TLS negotiation> <TLS negotiation>
C: A001 AUTHENTICATE SCRAM-SHA-256 C: A001 AUTHENTICATE SCRAM-SHA-256
biwsbj11c2VyLHI9ck9wck5HZndFYmVSV2diTkVrcU8= biwsbj11c2VyLHI9ck9wck5HZndFYmVSV2diTkVrcU8=
S: + cj1yT3ByTkdmd0ViZVJXZ2JORWtxTyVodllEcFdVYTJSYVRDQWZ1eEZJbGopaE5s S: + cj1yT3ByTkdmd0ViZVJXZ2JORWtxTyVodllEcFdVYTJSYVRDQWZ1eEZJbGopaE
RiRrMCxzPVcyMlphSjBTTlk3c29Fc1VFamI2Z1E9PSxpPTQwOTY= 5sRiRrMCxzPVcyMlphSjBTTlk3c29Fc1VFamI2Z1E9PSxpPTQwOTY=
C: Yz1iaXdzLHI9ck9wck5HZndFYmVSV2diTkVrcU8laHZZRHBXVWEyUmFUQ0FmdXhG C: Yz1iaXdzLHI9ck9wck5HZndFYmVSV2diTkVrcU8laHZZRHBXVWEyUmFUQ0FmdXhG
SWxqKWhObEYkazAscD1kSHpiWmFwV0lrNGpVaE4rVXRlOXl0YWc5empmTUhnc3Ft SWxqKWhObEYkazAscD1kSHpiWmFwV0lrNGpVaE4rVXRlOXl0YWc5empmTUhnc3Ft
bWl6N0FuZFZRPQ== bWl6N0FuZFZRPQ==
S: + dj02cnJpVFJCaTIzV3BSUi93dHVwK21NaFVaVW4vZEI1bkxUSlJzamw5NUc0PQ== S: + dj02cnJpVFJCaTIzV3BSUi93dHVwK21NaFVaVW4vZEI1bkxUSlJzamw5NUc0
C: PQ==
S: A001 OK SCRAM-SHA-256 authentication successful C:
C: babc ENABLE IMAP4rev2 S: A001 OK SCRAM-SHA-256 authentication successful
S: * ENABLED IMAP4rev2 C: babc ENABLE IMAP4rev2
S: babc OK Some capabilities enabled S: * ENABLED IMAP4rev2
C: a002 select inbox S: babc OK Some capabilities enabled
S: * 18 EXISTS C: a002 select inbox
S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft) S: * 18 EXISTS
S: * OK [UIDVALIDITY 3857529045] UIDs valid S: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
S: * LIST () "/" INBOX ("OLDNAME" ("inbox")) S: * OK [UIDVALIDITY 3857529045] UIDs valid
S: a002 OK [READ-WRITE] SELECT completed S: * LIST () "/" INBOX ("OLDNAME" ("inbox"))
C: a003 fetch 12 full S: a002 OK [READ-WRITE] SELECT completed
S: * 12 FETCH (FLAGS (\Seen) INTERNALDATE "17-Jul-1996 02:44:25 -0700" C: a003 fetch 12 full
RFC822.SIZE 4286 ENVELOPE ("Wed, 17 Jul 1996 02:23:25 -0700 (PDT)" S: * 12 FETCH (FLAGS (\Seen) INTERNALDATE
"IMAP4rev2 WG mtg summary and minutes" "17-Jul-1996 02:44:25 -0700" RFC822.SIZE 4286 ENVELOPE (
(("Terry Gray" NIL "gray" "cac.washington.edu")) "Wed, 17 Jul 1996 02:23:25 -0700 (PDT)"
(("Terry Gray" NIL "gray" "cac.washington.edu")) "IMAP4rev2 WG mtg summary and minutes"
(("Terry Gray" NIL "gray" "cac.washington.edu")) (("Terry Gray" NIL "gray" "cac.washington.edu"))
((NIL NIL "imap" "cac.washington.edu")) (("Terry Gray" NIL "gray" "cac.washington.edu"))
((NIL NIL "minutes" "CNRI.Reston.VA.US") (("Terry Gray" NIL "gray" "cac.washington.edu"))
("John Klensin" NIL "KLENSIN" "MIT.EDU")) NIL NIL ((NIL NIL "imap" "cac.washington.edu"))
"<B27397-0100000@cac.washington.edu>") ((NIL NIL "minutes" "CNRI.Reston.VA.US")
BODY ("TEXT" "PLAIN" ("CHARSET" "US-ASCII") NIL NIL "7BIT" 3028 ("John Klensin" NIL "KLENSIN" "MIT.EDU")) NIL NIL
92)) "<B27397-0100000@cac.washington.ed>")
S: a003 OK FETCH completed BODY ("TEXT" "PLAIN" ("CHARSET" "US-ASCII") NIL NIL "7BIT"
C: a004 fetch 12 body[header] 3028 92))
S: * 12 FETCH (BODY[HEADER] {342} S: a003 OK FETCH completed
S: Date: Wed, 17 Jul 1996 02:23:25 -0700 (PDT) C: a004 fetch 12 body[header]
S: From: Terry Gray <gray@cac.washington.edu> S: * 12 FETCH (BODY[HEADER] {342}
S: Subject: IMAP4rev2 WG mtg summary and minutes S: Date: Wed, 17 Jul 1996 02:23:25 -0700 (PDT)
S: To: imap@cac.washington.edu S: From: Terry Gray <gray@cac.washington.edu>
S: cc: minutes@CNRI.Reston.VA.US, John Klensin <KLENSIN@MIT.EDU> S: Subject: IMAP4rev2 WG mtg summary and minutes
S: Message-Id: <B27397-0100000@cac.washington.edu> S: To: imap@cac.washington.edu
S: MIME-Version: 1.0 S: cc: minutes@CNRI.Reston.VA.US, John Klensin <KLENSIN@MIT.EDU>
S: Content-Type: TEXT/PLAIN; CHARSET=US-ASCII S: Message-Id: <B27397-0100000@cac.washington.edu>
S: S: MIME-Version: 1.0
S: ) S: Content-Type: TEXT/PLAIN; CHARSET=US-ASCII
S: a004 OK FETCH completed S:
C: a005 store 12 +flags \deleted S: )
S: * 12 FETCH (FLAGS (\Seen \Deleted)) S: a004 OK FETCH completed
S: a005 OK +FLAGS completed C: a005 store 12 +flags \deleted
C: a006 logout S: * 12 FETCH (FLAGS (\Seen \Deleted))
S: * BYE IMAP4rev2 server terminating connection S: a005 OK +FLAGS completed
S: a006 OK LOGOUT completed C: a006 logout
S: * BYE IMAP4rev2 server terminating connection
S: a006 OK LOGOUT completed
9. Formal Syntax 9. Formal Syntax
The following syntax specification uses the Augmented Backus-Naur The following syntax specification uses the Augmented Backus-Naur
Form (ABNF) notation as specified in [ABNF]. Form (ABNF) notation as specified in [ABNF].
In the case of alternative or optional rules in which a later rule In the case of alternative or optional rules in which a later rule
overlaps an earlier rule, the rule which is listed earlier MUST take overlaps an earlier rule, the rule that is listed earlier MUST take
priority. For example, "\Seen" when parsed as a flag is the \Seen priority. For example, "\Seen" when parsed as a flag is the \Seen
flag name and not a flag-extension, even though "\Seen" can be parsed flag name and not a flag-extension, even though "\Seen" can be parsed
as a flag-extension. Some, but not all, instances of this rule are as a flag-extension. Some, but not all, instances of this rule are
noted below. noted below.
Note: [ABNF] rules MUST be followed strictly; in particular: Note: [ABNF] rules MUST be followed strictly; in particular:
(1) Except as noted otherwise, all alphabetic characters are case- 1. Unless otherwise noted, all alphabetic characters are case
insensitive. The use of upper or lower case characters to define insensitive. The use of uppercase or lowercase characters to
token strings is for editorial clarity only. Implementations MUST define token strings is for editorial clarity only.
accept these strings in a case-insensitive fashion. Implementations MUST accept these strings in a case-insensitive
fashion.
(2) In all cases, SP refers to exactly one space. It is NOT 2. In all cases, SP refers to exactly one space. It is NOT
permitted to substitute TAB, insert additional spaces, or permitted to substitute TAB, insert additional spaces, or
otherwise treat SP as being equivalent to LWSP. otherwise treat SP as being equivalent to linear whitespace
(LWSP).
(3) The ASCII NUL character, %x00, MUST NOT be used anywhere, with 3. The ASCII NUL character, %x00, MUST NOT be used anywhere, with
the exception of the OCTET production. the exception of the OCTET production.
SP = <Defined in RFC 5234> SP = <Defined in RFC 5234>
CTL = <Defined in RFC 5234> CTL = <Defined in RFC 5234>
CRLF = <Defined in RFC 5234> CRLF = <Defined in RFC 5234>
ALPHA = <Defined in RFC 5234> ALPHA = <Defined in RFC 5234>
DIGIT = <Defined in RFC 5234> DIGIT = <Defined in RFC 5234>
DQUOTE = <Defined in RFC 5234> DQUOTE = <Defined in RFC 5234>
OCTET = <Defined in RFC 5234> OCTET = <Defined in RFC 5234>
address = "(" addr-name SP addr-adl SP addr-mailbox SP address = "(" addr-name SP addr-adl SP addr-mailbox SP
addr-host ")" addr-host ")"
addr-adl = nstring addr-adl = nstring
; Holds route from [RFC-5322] obs-route if ; Holds route from [RFC5322] obs-route if
; non-NIL ; non-NIL
addr-host = nstring addr-host = nstring
; NIL indicates [RFC-5322] group syntax. ; NIL indicates [RFC5322] group syntax.
; Otherwise, holds [RFC-5322] domain name ; Otherwise, holds [RFC5322] domain name
addr-mailbox = nstring addr-mailbox = nstring
; NIL indicates end of [RFC-5322] group; if ; NIL indicates end of [RFC5322] group; if
; non-NIL and addr-host is NIL, holds ; non-NIL and addr-host is NIL, holds
; [RFC-5322] group name. ; [RFC5322] group name.
; Otherwise, holds [RFC-5322] local-part ; Otherwise, holds [RFC5322] local-part
; after removing [RFC-5322] quoting ; after removing [RFC5322] quoting
addr-name = nstring addr-name = nstring
; If non-NIL, holds phrase from [RFC-5322] ; If non-NIL, holds phrase from [RFC5322]
; mailbox after removing [RFC-5322] quoting ; mailbox after removing [RFC5322] quoting
append = "APPEND" SP mailbox [SP flag-list] [SP date-time] SP append = "APPEND" SP mailbox [SP flag-list] [SP date-time]
literal SP literal
append-uid = uniqueid append-uid = uniqueid
astring = 1*ASTRING-CHAR / string astring = 1*ASTRING-CHAR / string
ASTRING-CHAR = ATOM-CHAR / resp-specials ASTRING-CHAR = ATOM-CHAR / resp-specials
atom = 1*ATOM-CHAR
ATOM-CHAR = <any CHAR except atom-specials> atom = 1*ATOM-CHAR
atom-specials = "(" / ")" / "{" / SP / CTL / list-wildcards / ATOM-CHAR = <any CHAR except atom-specials>
quoted-specials / resp-specials
authenticate = "AUTHENTICATE" SP auth-type [SP initial-resp] atom-specials = "(" / ")" / "{" / SP / CTL / list-wildcards /
*(CRLF base64) quoted-specials / resp-specials
auth-type = atom authenticate = "AUTHENTICATE" SP auth-type [SP initial-resp]
; Defined by [SASL] *(CRLF base64)
base64 = *(4base64-char) [base64-terminal] auth-type = atom
; Authentication mechanism name, as defined by
; [SASL], Section 7.1
base64-char = ALPHA / DIGIT / "+" / "/" base64 = *(4base64-char) [base64-terminal]
; Case-sensitive
base64-terminal = (2base64-char "==") / (3base64-char "=") base64-char = ALPHA / DIGIT / "+" / "/"
; Case sensitive
body = "(" (body-type-1part / body-type-mpart) ")" base64-terminal = (2base64-char "==") / (3base64-char "=")
body-extension = nstring / number / number64 / body = "(" (body-type-1part / body-type-mpart) ")"
"(" body-extension *(SP body-extension) ")"
; Future expansion. Client implementations
; MUST accept body-extension fields. Server
; implementations MUST NOT generate
; body-extension fields except as defined by
; future standard or standards-track
; revisions of this specification.
body-ext-1part = body-fld-md5 [SP body-fld-dsp [SP body-fld-lang body-extension = nstring / number / number64 /
[SP body-fld-loc *(SP body-extension)]]] "(" body-extension *(SP body-extension) ")"
; MUST NOT be returned on non-extensible ; Future expansion. Client implementations
; "BODY" fetch ; MUST accept body-extension fields. Server
; implementations MUST NOT generate
; body-extension fields except as defined by
; future Standard or Standards Track
; revisions of this specification.
body-ext-mpart = body-fld-param [SP body-fld-dsp [SP body-fld-lang body-ext-1part = body-fld-md5 [SP body-fld-dsp [SP body-fld-lang
[SP body-fld-loc *(SP body-extension)]]] [SP body-fld-loc *(SP body-extension)]]]
; MUST NOT be returned on non-extensible ; MUST NOT be returned on non-extensible
; "BODY" fetch ; "BODY" fetch
body-fields = body-fld-param SP body-fld-id SP body-fld-desc SP body-ext-mpart = body-fld-param [SP body-fld-dsp [SP body-fld-lang
body-fld-enc SP body-fld-octets [SP body-fld-loc *(SP body-extension)]]]
; MUST NOT be returned on non-extensible
; "BODY" fetch
body-fld-desc = nstring body-fields = body-fld-param SP body-fld-id SP body-fld-desc SP
body-fld-enc SP body-fld-octets
body-fld-dsp = "(" string SP body-fld-param ")" / nil body-fld-desc = nstring
body-fld-enc = (DQUOTE ("7BIT" / "8BIT" / "BINARY" / "BASE64"/
"QUOTED-PRINTABLE") DQUOTE) / string
; Content-Transfer-Encoding header field value.
; Defaults to "7BIT" (as per RFC 2045)
; if not present in the body part.
body-fld-id = nstring body-fld-dsp = "(" string SP body-fld-param ")" / nil
body-fld-lang = nstring / "(" string *(SP string) ")" body-fld-enc = (DQUOTE ("7BIT" / "8BIT" / "BINARY" / "BASE64"/
"QUOTED-PRINTABLE") DQUOTE) / string
; Content-Transfer-Encoding header field value.
; Defaults to "7BIT" (as per RFC 2045)
; if not present in the body part.
body-fld-loc = nstring body-fld-id = nstring
body-fld-lines = number64 body-fld-lang = nstring / "(" string *(SP string) ")"
body-fld-md5 = nstring body-fld-loc = nstring
body-fld-octets = number body-fld-lines = number64
body-fld-param = "(" string SP string *(SP string SP string) ")" / nil body-fld-md5 = nstring
body-type-1part = (body-type-basic / body-type-msg / body-type-text) body-fld-octets = number
[SP body-ext-1part]
body-type-basic = media-basic SP body-fields body-fld-param = "(" string SP string *(SP string SP string) ")" /
; MESSAGE subtype MUST NOT be "RFC822" or "GLOBAL" nil
body-type-mpart = 1*body SP media-subtype body-type-1part = (body-type-basic / body-type-msg / body-type-text)
[SP body-ext-mpart] [SP body-ext-1part]
; MULTIPART body part
body-type-msg = media-message SP body-fields SP envelope body-type-basic = media-basic SP body-fields
SP body SP body-fld-lines ; MESSAGE subtype MUST NOT be "RFC822" or
; "GLOBAL"
body-type-text = media-text SP body-fields SP body-fld-lines body-type-mpart = 1*body SP media-subtype
[SP body-ext-mpart]
; MULTIPART body part
capability = ("AUTH=" auth-type) / atom body-type-msg = media-message SP body-fields SP envelope
; New capabilities SHOULD be SP body SP body-fld-lines
; registered with IANA using
; RFC Required policy, i.e. in
; a standards-track, an experimental
; or an informational RFC.
capability-data = "CAPABILITY" *(SP capability) SP "IMAP4rev2" body-type-text = media-text SP body-fields SP body-fld-lines
*(SP capability)
; Servers MUST implement the STARTTLS and LOGINDISABLED
; (on cleartext port), AUTH=PLAIN capabilities.
; Servers which offer RFC 1730 compatibility MUST
; list "IMAP4" as the first capability.
; Servers which offer RFC 3501 compatibility MUST capability = ("AUTH=" auth-type) / atom
; list "IMAP4rev1" as one of capabilities. ; New capabilities SHOULD be
; registered with IANA using the
; RFC Required policy, i.e., in
; a Standards Track, an Experimental,
; or an Informational RFC.
CHAR = <defined in [ABNF]> capability-data = "CAPABILITY" *(SP capability) SP "IMAP4rev2"
*(SP capability)
; See Section 6.1.1 for information about
; required security-related capabilities.
; Servers that offer RFC 1730 compatibility MUST
; list "IMAP4" as the first capability.
; Servers that offer RFC 3501 compatibility MUST
; list "IMAP4rev1" as one of the capabilities.
CHAR8 = %x01-ff CHAR = <defined in [ABNF]>
; any OCTET except NUL, %x00
charset = atom / quoted CHAR8 = %x01-ff
; any OCTET except NUL, %x00
childinfo-extended-item = "CHILDINFO" SP "(" charset = atom / quoted
list-select-base-opt-quoted
*(SP list-select-base-opt-quoted) ")"
; Extended data item (mbox-list-extended-item)
; returned when the RECURSIVEMATCH
; selection option is specified.
; Note 1: the CHILDINFO extended data item tag can be
; returned with and without surrounding quotes, as per
; mbox-list-extended-item-tag production.
; Note 2: The selection options are always returned
; quoted, unlike their specification in
; the extended LIST command.
child-mbox-flag = "\HasChildren" / "\HasNoChildren" childinfo-extended-item = "CHILDINFO" SP "("
; attributes for CHILDREN return option, at most one list-select-base-opt-quoted
; possible per LIST response *(SP list-select-base-opt-quoted) ")"
; Extended data item (mbox-list-extended-item)
; returned when the RECURSIVEMATCH
; selection option is specified.
; Note 1: the CHILDINFO extended data item tag can be
; returned with or without surrounding quotes, as per
; mbox-list-extended-item-tag production.
; Note 2: The selection options are always returned
; quoted, unlike their specification in
; the extended LIST command.
command = tag SP (command-any / command-auth / command-nonauth / child-mbox-flag = "\HasChildren" / "\HasNoChildren"
command-select) CRLF ; attributes for the CHILDREN return option, at most
; Modal based on state ; one possible per LIST response
command-any = "CAPABILITY" / "LOGOUT" / "NOOP" command = tag SP (command-any / command-auth /
; Valid in all states command-nonauth / command-select) CRLF
; Modal based on state
command-auth = append / create / delete / enable / examine / list / command-any = "CAPABILITY" / "LOGOUT" / "NOOP"
Namespace-Command / ; Valid in all states
rename / select / status / subscribe / unsubscribe /
idle
; Valid only in Authenticated or Selected state
command-nonauth = login / authenticate / "STARTTLS" command-auth = append / create / delete / enable / examine /
; Valid only when in Not Authenticated state list / namespace-command / rename /
select / status / subscribe / unsubscribe /
idle
; Valid only in Authenticated or Selected state
command-select = "CLOSE" / "UNSELECT" / "EXPUNGE" / copy / command-nonauth = login / authenticate / "STARTTLS"
move / fetch / store / search / uid ; Valid only when in Not Authenticated state
; Valid only when in Selected state
continue-req = "+" SP (resp-text / base64) CRLF command-select = "CLOSE" / "UNSELECT" / "EXPUNGE" / copy /
copy = "COPY" SP sequence-set SP mailbox move / fetch / store / search / uid
; Valid only when in Selected state
create = "CREATE" SP mailbox continue-req = "+" SP (resp-text / base64) CRLF
; Use of INBOX gives a NO error
date = date-text / DQUOTE date-text DQUOTE copy = "COPY" SP sequence-set SP mailbox
date-day = 1*2DIGIT create = "CREATE" SP mailbox
; Day of month ; Use of INBOX gives a NO error
date-day-fixed = (SP DIGIT) / 2DIGIT date = date-text / DQUOTE date-text DQUOTE
; Fixed-format version of date-day
date-month = "Jan" / "Feb" / "Mar" / "Apr" / "May" / "Jun" / date-day = 1*2DIGIT
"Jul" / "Aug" / "Sep" / "Oct" / "Nov" / "Dec" ; Day of month
date-text = date-day "-" date-month "-" date-year date-day-fixed = (SP DIGIT) / 2DIGIT
; Fixed-format version of date-day
date-year = 4DIGIT date-month = "Jan" / "Feb" / "Mar" / "Apr" / "May" / "Jun" /
"Jul" / "Aug" / "Sep" / "Oct" / "Nov" / "Dec"
date-time = DQUOTE date-day-fixed "-" date-month "-" date-year date-text = date-day "-" date-month "-" date-year
SP time SP zone DQUOTE
delete = "DELETE" SP mailbox date-year = 4DIGIT
; Use of INBOX gives a NO error
digit-nz = %x31-39 date-time = DQUOTE date-day-fixed "-" date-month "-" date-year
; 1-9 SP time SP zone DQUOTE
eitem-standard-tag = atom delete = "DELETE" SP mailbox
; a tag for LIST extended data item defined in a Standard ; Use of INBOX gives a NO error
; Track or Experimental RFC.
eitem-vendor-tag = vendor-token "-" atom digit-nz = %x31-39
; a vendor-specific tag for LIST extended data item ; 1-9
enable = "ENABLE" 1*(SP capability) eitem-standard-tag = atom
; a tag for LIST extended data item defined in a Standard
; Track or Experimental RFC.
enable-data = "ENABLED" *(SP capability) eitem-vendor-tag = vendor-token "-" atom
; a vendor-specific tag for LIST extended data item
envelope = "(" env-date SP env-subject SP env-from SP enable = "ENABLE" 1*(SP capability)
env-sender SP env-reply-to SP env-to SP env-cc SP
env-bcc SP env-in-reply-to SP env-message-id ")"
env-bcc = "(" 1*address ")" / nil enable-data = "ENABLED" *(SP capability)
env-cc = "(" 1*address ")" / nil envelope = "(" env-date SP env-subject SP env-from SP
env-date = nstring env-sender SP env-reply-to SP env-to SP env-cc SP
env-bcc SP env-in-reply-to SP env-message-id ")"
env-from = "(" 1*address ")" / nil env-bcc = "(" 1*address ")" / nil
env-in-reply-to = nstring env-cc = "(" 1*address ")" / nil
env-message-id = nstring env-date = nstring
env-reply-to = "(" 1*address ")" / nil env-from = "(" 1*address ")" / nil
env-sender = "(" 1*address ")" / nil env-in-reply-to = nstring
env-subject = nstring env-message-id = nstring
env-to = "(" 1*address ")" / nil env-reply-to = "(" 1*address ")" / nil
esearch-response = "ESEARCH" [search-correlator] [SP "UID"] env-sender = "(" 1*address ")" / nil
*(SP search-return-data)
; ESEARCH response replaces SEARCH response
; from IMAP4rev1.
examine = "EXAMINE" SP mailbox env-subject = nstring
fetch = "FETCH" SP sequence-set SP ("ALL" / "FULL" / "FAST" / env-to = "(" 1*address ")" / nil
fetch-att / "(" fetch-att *(SP fetch-att) ")")
fetch-att = "ENVELOPE" / "FLAGS" / "INTERNALDATE" / esearch-response = "ESEARCH" [search-correlator] [SP "UID"]
"RFC822.SIZE" / *(SP search-return-data)
"BODY" ["STRUCTURE"] / "UID" / ; ESEARCH response replaces SEARCH response
"BODY" section [partial] / ; from IMAP4rev1.
"BODY.PEEK" section [partial] /
"BINARY" [".PEEK"] section-binary [partial] /
"BINARY.SIZE" section-binary
flag = "\Answered" / "\Flagged" / "\Deleted" / examine = "EXAMINE" SP mailbox
"\Seen" / "\Draft" / flag-keyword / flag-extension
; Does not include "\Recent"
flag-extension = "\" atom fetch = "FETCH" SP sequence-set SP (
; Future expansion. Client implementations "ALL" / "FULL" / "FAST" /
; MUST accept flag-extension flags. Server fetch-att / "(" fetch-att *(SP fetch-att) ")")
; implementations MUST NOT generate
; flag-extension flags except as defined by
; future standard or standards-track
; revisions of this specification.
; "\Recent" was defined in RFC 3501
; and is now deprecated.
flag-fetch = flag fetch-att = "ENVELOPE" / "FLAGS" / "INTERNALDATE" /
"RFC822.SIZE" /
"BODY" ["STRUCTURE"] / "UID" /
"BODY" section [partial] /
"BODY.PEEK" section [partial] /
"BINARY" [".PEEK"] section-binary [partial] /
"BINARY.SIZE" section-binary
flag-keyword = "$MDNSent" / "$Forwarded" / "$Junk" / flag = "\Answered" / "\Flagged" / "\Deleted" /
"$NotJunk" / "$Phishing" / atom "\Seen" / "\Draft" / flag-keyword / flag-extension
; Does not include "\Recent"
flag-list = "(" [flag *(SP flag)] ")" flag-extension = "\" atom
; Future expansion. Client implementations
; MUST accept flag-extension flags. Server
; implementations MUST NOT generate
; flag-extension flags except as defined by
; a future Standard or Standards Track
; revisions of this specification.
; "\Recent" was defined in RFC 3501
; and is now deprecated.
flag-perm = flag / "\*" flag-fetch = flag / obsolete-flag-recent
greeting = "*" SP (resp-cond-auth / resp-cond-bye) CRLF flag-keyword = "$MDNSent" / "$Forwarded" / "$Junk" /
"$NotJunk" / "$Phishing" / atom
header-fld-name = astring flag-list = "(" [flag *(SP flag)] ")"
header-list = "(" header-fld-name *(SP header-fld-name) ")" flag-perm = flag / "\*"
idle = "IDLE" CRLF "DONE" greeting = "*" SP (resp-cond-auth / resp-cond-bye) CRLF
initial-resp = (base64 / "=") header-fld-name = astring
; "initial response" defined in
; Section 5.1 of [RFC4422]
list = "LIST" [SP list-select-opts] SP mailbox SP mbox-or-pat header-list = "(" header-fld-name *(SP header-fld-name) ")"
[SP list-return-opts]
list-mailbox = 1*list-char / string idle = "IDLE" CRLF "DONE"
list-char = ATOM-CHAR / list-wildcards / resp-specials initial-resp = (base64 / "=")
; "initial response" defined in
; Section 4 of [SASL]
list-return-opt = return-option list = "LIST" [SP list-select-opts] SP
; Note that return-option is the ABNF mailbox SP mbox-or-pat
; non terminal used by RFC 5258 [SP list-return-opts]
list-return-opts = "RETURN" SP list-mailbox = 1*list-char / string
"(" [list-return-opt *(SP list-return-opt)] ")"
; list return options, e.g., CHILDREN
list-select-base-opt = "SUBSCRIBED" / option-extension list-char = ATOM-CHAR / list-wildcards / resp-specials
; options that can be used by themselves
list-select-base-opt-quoted = DQUOTE list-select-base-opt DQUOTE list-return-opt = return-option
; Note that return-option is the ABNF
; non-terminal used by RFC 5258
list-select-independent-opt = "REMOTE" / option-extension list-return-opts = "RETURN" SP
; options that do not syntactically interact with "(" [list-return-opt *(SP list-return-opt)] ")"
; other options ; list return options, e.g., CHILDREN
list-select-mod-opt = "RECURSIVEMATCH" / option-extension list-select-base-opt = "SUBSCRIBED" / option-extension
; options that require a list-select-base-opt ; options that can be used by themselves
; to also be present
list-select-opt = list-select-base-opt / list-select-independent-opt list-select-base-opt-quoted = DQUOTE list-select-base-opt DQUOTE
/ list-select-mod-opt
; An option registration template is described in
; Section 9.3 of this document.
list-select-opts = "(" [ list-select-independent-opt = "REMOTE" / option-extension
(*(list-select-opt SP) list-select-base-opt ; options that do not syntactically interact with
*(SP list-select-opt)) ; other options
/ (list-select-independent-opt
*(SP list-select-independent-opt))
] ")"
; Any number of options may be in any order.
; If a list-select-mod-opt appears, then a
; list-select-base-opt must also appear.
; This allows these:
; ()
; (REMOTE)
; (SUBSCRIBED)
; (SUBSCRIBED REMOTE)
; (SUBSCRIBED RECURSIVEMATCH)
; (SUBSCRIBED REMOTE RECURSIVEMATCH)
; But does NOT allow these:
; (RECURSIVEMATCH)
; (REMOTE RECURSIVEMATCH)
list-wildcards = "%" / "*" list-select-mod-opt = "RECURSIVEMATCH" / option-extension
; options that require a list-select-base-opt
; to also be present
literal = "{" number64 ["+"] "}" CRLF *CHAR8 list-select-opt = list-select-base-opt / list-select-independent-opt
; <number64> represents the number of CHAR8s. / list-select-mod-opt
; A non-synchronizing literal is distinguished from
; a synchronizing literal by presence of the "+"
; before the closing "}".
; Non synchronizing literals are not allowed when
; sent from server to the client.
literal8 = "~{" number64 "}" CRLF *OCTET list-select-opts = "(" [
; <number64> represents the number of OCTETs (*(list-select-opt SP) list-select-base-opt
; in the response string. *(SP list-select-opt))
/ (list-select-independent-opt
*(SP list-select-independent-opt))
] ")"
; Any number of options may be in any order.
; If a list-select-mod-opt appears, then a
; list-select-base-opt must also appear.
; This allows these:
; ()
; (REMOTE)
; (SUBSCRIBED)
; (SUBSCRIBED REMOTE)
; (SUBSCRIBED RECURSIVEMATCH)
; (SUBSCRIBED REMOTE RECURSIVEMATCH)
; But does NOT allow these:
; (RECURSIVEMATCH)
; (REMOTE RECURSIVEMATCH)
login = "LOGIN" SP userid SP password list-wildcards = "%" / "*"
mailbox = "INBOX" / astring literal = "{" number64 ["+"] "}" CRLF *CHAR8
; INBOX is case-insensitive. All case variants of ; <number64> represents the number of CHAR8s.
; INBOX (e.g., "iNbOx") MUST be interpreted as INBOX ; A non-synchronizing literal is distinguished
; not as an astring. An astring which consists of ; from a synchronizing literal by the presence of
; the case-insensitive sequence "I" "N" "B" "O" "X" ; "+" before the closing "}".
; is considered to be INBOX and not an astring. ; Non-synchronizing literals are not allowed when
; Refer to section 5.1 for further ; sent from server to the client.
; semantic details of mailbox names.
mailbox-data = "FLAGS" SP flag-list / "LIST" SP mailbox-list / literal8 = "~{" number64 "}" CRLF *OCTET
esearch-response / ; <number64> represents the number of OCTETs
"STATUS" SP mailbox SP "(" [status-att-list] ")" / ; in the response string.
number SP "EXISTS" / Namespace-Response
mailbox-list = "(" [mbx-list-flags] ")" SP login = "LOGIN" SP userid SP password
(DQUOTE QUOTED-CHAR DQUOTE / nil) SP mailbox
[SP mbox-list-extended]
; This is the list information pointed to by the ABNF
; item "mailbox-data", which is defined in [IMAP4]
mbox-list-extended = "(" [mbox-list-extended-item mailbox = "INBOX" / astring
*(SP mbox-list-extended-item)] ")" ; INBOX is case insensitive. All case variants
; of INBOX (e.g., "iNbOx") MUST be interpreted as
; INBOX, not as an astring. An astring that
; consists of the case-insensitive sequence
; "I" "N" "B" "O" "X" is considered
; to be an INBOX and not an astring.
; Refer to Section 5.1 for further
; semantic details of mailbox names.
mbox-list-extended-item = mbox-list-extended-item-tag SP mailbox-data = "FLAGS" SP flag-list / "LIST" SP mailbox-list /
tagged-ext-val esearch-response /
"STATUS" SP mailbox SP "(" [status-att-list] ")" /
number SP "EXISTS" / namespace-response /
obsolete-search-response /
obsolete-recent-response
; obsolete-search-response and
; obsolete-recent-response can only be returned
; by servers that support both IMAPrev1
; and IMAPrev2.
mbox-list-extended-item-tag = astring mailbox-list = "(" [mbx-list-flags] ")" SP
; The content MUST conform to either "eitem-vendor-tag" (DQUOTE QUOTED-CHAR DQUOTE / nil) SP mailbox
; or "eitem-standard-tag" ABNF productions. [SP mbox-list-extended]
; This is the list information pointed to by the ABNF
; item "mailbox-data", which is defined above
mbox-or-pat = list-mailbox / patterns mbox-list-extended = "(" [mbox-list-extended-item
*(SP mbox-list-extended-item)] ")"
mbx-list-flags = *(mbx-list-oflag SP) mbx-list-sflag mbox-list-extended-item = mbox-list-extended-item-tag SP
*(SP mbx-list-oflag) / tagged-ext-val
mbx-list-oflag *(SP mbx-list-oflag)
mbx-list-oflag = "\Noinferiors" / child-mbox-flag / mbox-list-extended-item-tag = astring
"\Subscribed" / "\Remote" / flag-extension ; The content MUST conform to either
; Other flags; multiple possible per LIST response ; "eitem-vendor-tag" or "eitem-standard-tag"
; ABNF productions.
mbx-list-sflag = "\NonExistent" / "\Noselect" / "\Marked" / "\Unmarked" mbox-or-pat = list-mailbox / patterns
; Selectability flags; only one per LIST response
media-basic = ((DQUOTE ("APPLICATION" / "AUDIO" / "IMAGE" / mbx-list-flags = *(mbx-list-oflag SP) mbx-list-sflag
"FONT" / "MESSAGE" / "MODEL" / "VIDEO" ) DQUOTE) *(SP mbx-list-oflag) /
/ string) mbx-list-oflag *(SP mbx-list-oflag)
SP media-subtype
; FONT defined in RFC 8081.
; MODEL defined in RFC 2077.
; Other top level media types
; are defined in [MIME-IMT].
media-message = DQUOTE "MESSAGE" DQUOTE SP mbx-list-oflag = "\Noinferiors" / child-mbox-flag /
DQUOTE ("RFC822" / "GLOBAL") DQUOTE "\Subscribed" / "\Remote" / flag-extension
; Defined in [MIME-IMT] ; Other flags; multiple from this list are
; possible per LIST response, but each flag
; can only appear once per LIST response
media-subtype = string mbx-list-sflag = "\NonExistent" / "\Noselect" / "\Marked" /
; Defined in [MIME-IMT] "\Unmarked"
; Selectability flags; only one per LIST response
media-text = DQUOTE "TEXT" DQUOTE SP media-subtype media-basic = ((DQUOTE ("APPLICATION" / "AUDIO" / "IMAGE" /
; Defined in [MIME-IMT] "FONT" / "MESSAGE" / "MODEL" / "VIDEO" ) DQUOTE)
/ string)
SP media-subtype
; FONT defined in [RFC8081].
; MODEL defined in [RFC2077].
; Other top-level media types
; are defined in [MIME-IMT].
message-data = nz-number SP ("EXPUNGE" / ("FETCH" SP msg-att)) media-message = DQUOTE "MESSAGE" DQUOTE SP
DQUOTE ("RFC822" / "GLOBAL") DQUOTE
; Defined in [MIME-IMT]
move = "MOVE" SP sequence-set SP mailbox media-subtype = string
; Defined in [MIME-IMT]
msg-att = "(" (msg-att-dynamic / msg-att-static) media-text = DQUOTE "TEXT" DQUOTE SP media-subtype
*(SP (msg-att-dynamic / msg-att-static)) ")" ; Defined in [MIME-IMT]
msg-att-dynamic = "FLAGS" SP "(" [flag-fetch *(SP flag-fetch)] ")" message-data = nz-number SP ("EXPUNGE" / ("FETCH" SP msg-att))
; MAY change for a message
msg-att-static = "ENVELOPE" SP envelope / "INTERNALDATE" SP date-time / move = "MOVE" SP sequence-set SP mailbox
"RFC822.SIZE" SP number64 /
"BODY" ["STRUCTURE"] SP body /
"BODY" section ["<" number ">"] SP nstring /
"BINARY" section-binary SP (nstring / literal8) /
"BINARY.SIZE" section-binary SP number /
"UID" SP uniqueid
; MUST NOT change for a message
name-component = 1*UTF8-CHAR msg-att = "(" (msg-att-dynamic / msg-att-static)
; MUST NOT contain ".", "/", "%", or "*" *(SP (msg-att-dynamic / msg-att-static)) ")"
namespace = nil / "(" 1*namespace-descr ")" msg-att-dynamic = "FLAGS" SP "(" [flag-fetch *(SP flag-fetch)] ")"
; MAY change for a message
namespace-command = "NAMESPACE" msg-att-static = "ENVELOPE" SP envelope /
"INTERNALDATE" SP date-time /
"RFC822.SIZE" SP number64 /
"BODY" ["STRUCTURE"] SP body /
"BODY" section ["<" number ">"] SP nstring /
"BINARY" section-binary SP (nstring / literal8) /
"BINARY.SIZE" section-binary SP number /
"UID" SP uniqueid
; MUST NOT change for a message
namespace-descr = "(" string SP name-component = 1*UTF8-CHAR
(DQUOTE QUOTED-CHAR DQUOTE / nil) ; MUST NOT contain ".", "/", "%", or "*"
[namespace-response-extensions] ")"
namespace-response-extensions = *namespace-response-extension namespace = nil / "(" 1*namespace-descr ")"
namespace-response-extension = SP string SP namespace-command = "NAMESPACE"
"(" string *(SP string) ")"
namespace-response = "NAMESPACE" SP namespace namespace-descr = "(" string SP
SP namespace SP namespace (DQUOTE QUOTED-CHAR DQUOTE / nil)
[namespace-response-extensions] ")"
namespace-response-extensions = *namespace-response-extension
namespace-response-extension = SP string SP
"(" string *(SP string) ")"
namespace-response = "NAMESPACE" SP namespace
SP namespace SP namespace
; The first Namespace is the Personal Namespace(s). ; The first Namespace is the Personal Namespace(s).
; The second Namespace is the Other Users' ; The second Namespace is the Other Users'
; Namespace(s). ; Namespace(s).
; The third Namespace is the Shared Namespace(s). ; The third Namespace is the Shared Namespace(s).
nil = "NIL" nil = "NIL"
nstring = string / nil nstring = string / nil
number = 1*DIGIT number = 1*DIGIT
; Unsigned 32-bit integer ; Unsigned 32-bit integer
; (0 <= n < 4,294,967,296) ; (0 <= n < 4,294,967,296)
number64 = 1*DIGIT number64 = 1*DIGIT
; Unsigned 63-bit integer ; Unsigned 63-bit integer
; (0 <= n <= 9,223,372,036,854,775,807) ; (0 <= n <= 9,223,372,036,854,775,807)
nz-number = digit-nz *DIGIT nz-number = digit-nz *DIGIT
; Non-zero unsigned 32-bit integer ; Non-zero unsigned 32-bit integer
; (0 < n < 4,294,967,296) ; (0 < n < 4,294,967,296)
nz-number64 = digit-nz *DIGIT nz-number64 = digit-nz *DIGIT
; Unsigned 63-bit integer ; Unsigned 63-bit integer
; (0 < n <= 9,223,372,036,854,775,807) ; (0 < n <= 9,223,372,036,854,775,807)
oldname-extended-item = "OLDNAME" SP "(" mailbox ")" obsolete-flag-recent = "\Recent"
; Extended data item (mbox-list-extended-item)
; returned in a LIST response when a mailbox is
; renamed or deleted. Also returned when
; the server canonicalized the provided mailbox
; name.
; Note 1: the OLDNAME tag can be returned
; with or without surrounding quotes, as per
; mbox-list-extended-item-tag production.
option-extension = (option-standard-tag / option-vendor-tag) obsolete-recent-response = number SP "RECENT"
[SP option-value]
option-standard-tag = atom obsolete-search-response = "SEARCH" *(SP nz-number)
; an option defined in a Standards Track or
; Experimental RFC
option-val-comp = astring / oldname-extended-item = "OLDNAME" SP "(" mailbox ")"
option-val-comp *(SP option-val-comp) / ; Extended data item (mbox-list-extended-item)
"(" option-val-comp ")" ; returned in a LIST response when a mailbox is
; renamed or deleted. Also returned when
; the server canonicalized the provided mailbox
; name.
; Note 1: the OLDNAME tag can be returned
; with or without surrounding quotes, as per
; mbox-list-extended-item-tag production.
option-value = "(" option-val-comp ")" option-extension = (option-standard-tag / option-vendor-tag)
[SP option-value]
option-vendor-tag = vendor-token "-" atom option-standard-tag = atom
; a vendor-specific option, non-standard ; an option defined in a Standards Track or
; Experimental RFC
partial-range = number64 ["." nz-number64] option-val-comp = astring /
; Copied from RFC 5092 (IMAP URL) option-val-comp *(SP option-val-comp) /
; and updated to support 64bit sizes. "(" option-val-comp ")"
partial = "<" number64 "." nz-number64 ">" option-value = "(" option-val-comp ")"
; Partial FETCH request. 0-based offset of
; the first octet, followed by the number of octets
; in the fragment.
password = astring option-vendor-tag = vendor-token "-" atom
; a vendor-specific option, non-standard
patterns = "(" list-mailbox ")" partial-range = number64 ["." nz-number64]
; [RFC5258] supports multiple patterns, ; Copied from RFC 5092 (IMAP URL)
; but this document only requires one ; and updated to support 64-bit sizes.
; to be supported.
; If the server is also implementing
; [RFC5258], "patterns" syntax from that
; document must be followed.
quoted = DQUOTE *QUOTED-CHAR DQUOTE partial = "<" number64 "." nz-number64 ">"
; Partial FETCH request. 0-based offset of
; the first octet, followed by the number of
; octets in the fragment.
QUOTED-CHAR = <any TEXT-CHAR except quoted-specials> / password = astring
"\" quoted-specials / UTF8-2 / UTF8-3 / UTF8-4
quoted-specials = DQUOTE / "\" patterns = "(" list-mailbox ")"
; [RFC5258] supports multiple patterns,
; but this document only requires one
; to be supported.
; If the server is also implementing
; [RFC5258], the "patterns" syntax from
; that document must be followed.
rename = "RENAME" SP mailbox SP mailbox quoted = DQUOTE *QUOTED-CHAR DQUOTE
; Use of INBOX as a destination gives a NO error
response = *(continue-req / response-data) response-done QUOTED-CHAR = <any TEXT-CHAR except quoted-specials> /
"\" quoted-specials / UTF8-2 / UTF8-3 / UTF8-4
response-data = "*" SP (resp-cond-state / resp-cond-bye / quoted-specials = DQUOTE / "\"
mailbox-data / message-data / capability-data /
enable-data) CRLF
response-done = response-tagged / response-fatal rename = "RENAME" SP mailbox SP mailbox
; Use of INBOX as a destination gives a NO error
response-fatal = "*" SP resp-cond-bye CRLF response = *(continue-req / response-data) response-done
; Server closes connection immediately
response-tagged = tag SP resp-cond-state CRLF response-data = "*" SP (resp-cond-state / resp-cond-bye /
mailbox-data / message-data / capability-data /
enable-data) CRLF
resp-code-apnd = "APPENDUID" SP nz-number SP append-uid response-done = response-tagged / response-fatal
resp-code-copy = "COPYUID" SP nz-number SP uid-set SP uid-set response-fatal = "*" SP resp-cond-bye CRLF
resp-cond-auth = ("OK" / "PREAUTH") SP resp-text ; Server closes connection immediately
; Authentication condition
resp-cond-bye = "BYE" SP resp-text response-tagged = tag SP resp-cond-state CRLF
resp-cond-state = ("OK" / "NO" / "BAD") SP resp-text resp-code-apnd = "APPENDUID" SP nz-number SP append-uid
; Status condition
resp-specials = "]" resp-code-copy = "COPYUID" SP nz-number SP uid-set SP uid-set
resp-text = ["[" resp-text-code "]" SP] [text] resp-cond-auth = ("OK" / "PREAUTH") SP resp-text
; Authentication condition
resp-text-code = "ALERT" / resp-cond-bye = "BYE" SP resp-text
"BADCHARSET" [SP "(" charset *(SP charset) ")" ] /
capability-data / "PARSE" /
"PERMANENTFLAGS" SP
"(" [flag-perm *(SP flag-perm)] ")" /
"READ-ONLY" / "READ-WRITE" / "TRYCREATE" /
"UIDNEXT" SP nz-number / "UIDVALIDITY" SP nz-number /
resp-code-apnd / resp-code-copy / "UIDNOTSTICKY" /
"UNAVAILABLE" / "AUTHENTICATIONFAILED" /
"AUTHORIZATIONFAILED" / "EXPIRED" /
"PRIVACYREQUIRED" / "CONTACTADMIN" / "NOPERM" /
"INUSE" / "EXPUNGEISSUED" / "CORRUPTION" /
"SERVERBUG" / "CLIENTBUG" / "CANNOT" /
"LIMIT" / "OVERQUOTA" / "ALREADYEXISTS" /
"NONEXISTENT" / "NOTSAVED" / "HASCHILDREN" /
"CLOSED" /
"UNKNOWN-CTE" /
atom [SP 1*<any TEXT-CHAR except "]">]
return-option = "SUBSCRIBED" / "CHILDREN" / status-option / resp-cond-state = ("OK" / "NO" / "BAD") SP resp-text
option-extension ; Status condition
search = "SEARCH" [search-return-opts] resp-specials = "]"
SP search-program
search-correlator = SP "(" "TAG" SP tag-string ")" resp-text = ["[" resp-text-code "]" SP] [text]
search-key = "ALL" / "ANSWERED" / "BCC" SP astring / resp-text-code = "ALERT" /
"BEFORE" SP date / "BODY" SP astring / "BADCHARSET" [SP "(" charset *(SP charset) ")" ] /
"CC" SP astring / "DELETED" / "FLAGGED" / capability-data / "PARSE" /
"FROM" SP astring / "KEYWORD" SP flag-keyword / "PERMANENTFLAGS" SP
"ON" SP date / "SEEN" / "(" [flag-perm *(SP flag-perm)] ")" /
"SINCE" SP date / "SUBJECT" SP astring / "READ-ONLY" / "READ-WRITE" / "TRYCREATE" /
"TEXT" SP astring / "TO" SP astring / "UIDNEXT" SP nz-number /
"UNANSWERED" / "UNDELETED" / "UNFLAGGED" / "UIDVALIDITY" SP nz-number /
"UNKEYWORD" SP flag-keyword / "UNSEEN" / resp-code-apnd / resp-code-copy / "UIDNOTSTICKY" /
; Above this line were in [IMAP2] "UNAVAILABLE" / "AUTHENTICATIONFAILED" /
"DRAFT" / "HEADER" SP header-fld-name SP astring / "AUTHORIZATIONFAILED" / "EXPIRED" /
"LARGER" SP number64 / "NOT" SP search-key / "PRIVACYREQUIRED" / "CONTACTADMIN" / "NOPERM" /
"OR" SP search-key SP search-key / "INUSE" / "EXPUNGEISSUED" / "CORRUPTION" /
"SENTBEFORE" SP date / "SENTON" SP date / "SERVERBUG" / "CLIENTBUG" / "CANNOT" /
"SENTSINCE" SP date / "SMALLER" SP number64 / "LIMIT" / "OVERQUOTA" / "ALREADYEXISTS" /
"UID" SP sequence-set / "UNDRAFT" / sequence-set / "NONEXISTENT" / "NOTSAVED" / "HASCHILDREN" /
"(" search-key *(SP search-key) ")" "CLOSED" /
"UNKNOWN-CTE" /
atom [SP 1*<any TEXT-CHAR except "]">]
search-modifier-name = tagged-ext-label return-option = "SUBSCRIBED" / "CHILDREN" / status-option /
option-extension
search-mod-params = tagged-ext-val search = "SEARCH" [search-return-opts]
; This non-terminal shows recommended syntax SP search-program
; for future extensions.
search-program = ["CHARSET" SP charset SP] search-correlator = SP "(" "TAG" SP tag-string ")"
search-key *(SP search-key)
; CHARSET argument to SEARCH MUST be
; registered with IANA.
search-ret-data-ext = search-modifier-name SP search-return-value search-key = "ALL" / "ANSWERED" / "BCC" SP astring /
; Note that not every SEARCH return option "BEFORE" SP date / "BODY" SP astring /
; is required to have the corresponding "CC" SP astring / "DELETED" / "FLAGGED" /
; ESEARCH return data. "FROM" SP astring / "KEYWORD" SP flag-keyword /
"ON" SP date / "SEEN" /
"SINCE" SP date / "SUBJECT" SP astring /
"TEXT" SP astring / "TO" SP astring /
"UNANSWERED" / "UNDELETED" / "UNFLAGGED" /
"UNKEYWORD" SP flag-keyword / "UNSEEN" /
; Above this line were in [IMAP2]
"DRAFT" / "HEADER" SP header-fld-name SP astring /
"LARGER" SP number64 / "NOT" SP search-key /
"OR" SP search-key SP search-key /
"SENTBEFORE" SP date / "SENTON" SP date /
"SENTSINCE" SP date / "SMALLER" SP number64 /
"UID" SP sequence-set / "UNDRAFT" / sequence-set /
"(" search-key *(SP search-key) ")"
search-return-data = "MIN" SP nz-number / search-modifier-name = tagged-ext-label
"MAX" SP nz-number /
"ALL" SP sequence-set /
"COUNT" SP number /
search-ret-data-ext
; All return data items conform to
; search-ret-data-ext syntax.
; Note that "$" marker is not allowed
; after the ALL return data item.
search-return-opts = SP "RETURN" SP "(" [search-return-opt search-mod-params = tagged-ext-val
*(SP search-return-opt)] ")" ; This non-terminal shows recommended syntax
; for future extensions.
search-return-opt = "MIN" / "MAX" / "ALL" / "COUNT" / search-program = ["CHARSET" SP charset SP]
"SAVE" / search-key *(SP search-key)
search-ret-opt-ext ; CHARSET argument to SEARCH MUST be
; conforms to generic search-ret-opt-ext ; registered with IANA.
; syntax
search-ret-opt-ext = search-modifier-name [SP search-mod-params] search-ret-data-ext = search-modifier-name SP search-return-value
; Note that not every SEARCH return option
; is required to have the corresponding
; ESEARCH return data.
search-return-value = tagged-ext-val search-return-data = "MIN" SP nz-number /
; Data for the returned search option. "MAX" SP nz-number /
"ALL" SP sequence-set /
"COUNT" SP number /
search-ret-data-ext
; All return data items conform to
; search-ret-data-ext syntax.
; Note that "$" marker is not allowed
; after the ALL return data item.
; A single "nz-number"/"number"/"number64" value search-return-opts = SP "RETURN" SP "(" [search-return-opt
; can be returned as an atom (i.e., without *(SP search-return-opt)] ")"
; quoting). A sequence-set can be returned
; as an atom as well.
section = "[" [section-spec] "]" search-return-opt = "MIN" / "MAX" / "ALL" / "COUNT" /
"SAVE" /
search-ret-opt-ext
; conforms to generic search-ret-opt-ext
; syntax
section-binary = "[" [section-part] "]" search-ret-opt-ext = search-modifier-name [SP search-mod-params]
section-msgtext = "HEADER" / "HEADER.FIELDS" [".NOT"] SP header-list / search-return-value = tagged-ext-val
"TEXT" ; Data for the returned search option.
; top-level or MESSAGE/RFC822 or MESSAGE/GLOBAL part ; A single "nz-number"/"number"/"number64" value
; can be returned as an atom (i.e., without
; quoting). A sequence-set can be returned
; as an atom as well.
section-part = nz-number *("." nz-number) section = "[" [section-spec] "]"
; body part reference.
; Allows for accessing nested body parts.
section-spec = section-msgtext / (section-part ["." section-text]) section-binary = "[" [section-part] "]"
section-text = section-msgtext / "MIME" section-msgtext = "HEADER" /
; text other than actual body part (headers, etc.) "HEADER.FIELDS" [".NOT"] SP header-list /
"TEXT"
; top-level or MESSAGE/RFC822 or
; MESSAGE/GLOBAL part
select = "SELECT" SP mailbox section-part = nz-number *("." nz-number)
; body part reference.
; Allows for accessing nested body parts.
seq-number = nz-number / "*" section-spec = section-msgtext / (section-part ["." section-text])
; message sequence number (COPY, FETCH, STORE
; commands) or unique identifier (UID COPY,
; UID FETCH, UID STORE commands).
; * represents the largest number in use. In
; the case of message sequence numbers, it is
; the number of messages in a non-empty mailbox.
; In the case of unique identifiers, it is the
; unique identifier of the last message in the
; mailbox or, if the mailbox is empty, the
; mailbox's current UIDNEXT value.
; The server should respond with a tagged BAD
; response to a command that uses a message
; sequence number greater than the number of
; messages in the selected mailbox. This
; includes "*" if the selected mailbox is empty.
seq-range = seq-number ":" seq-number section-text = section-msgtext / "MIME"
; two seq-number values and all values between ; text other than actual body part (headers,
; these two regardless of order. ; etc.)
; Example: 2:4 and 4:2 are equivalent and indicate
; values 2, 3, and 4.
; Example: a unique identifier sequence range of
; 3291:* includes the UID of the last message in
; the mailbox, even if that value is less than 3291.
sequence-set = (seq-number / seq-range) ["," sequence-set] select = "SELECT" SP mailbox
; set of seq-number values, regardless of order.
; Servers MAY coalesce overlaps and/or execute the
; sequence in any order.
; Example: a message sequence number set of
; 2,4:7,9,12:* for a mailbox with 15 messages is
; equivalent to 2,4,5,6,7,9,12,13,14,15
; Example: a message sequence number set of *:4,5:7
; for a mailbox with 10 messages is equivalent to
; 10,9,8,7,6,5,4,5,6,7 and MAY be reordered and
; overlap coalesced to be 4,5,6,7,8,9,10.
sequence-set =/ seq-last-command seq-number = nz-number / "*"
; Allow for "result of the last command" indicator. ; message sequence number (COPY, FETCH, STORE
; commands) or unique identifier (UID COPY,
; UID FETCH, UID STORE commands).
; * represents the largest number in use. In
; the case of message sequence numbers, it is
; the number of messages in a non-empty mailbox.
; In the case of unique identifiers, it is the
; unique identifier of the last message in the
; mailbox or, if the mailbox is empty, the
; mailbox's current UIDNEXT value.
; The server should respond with a tagged BAD
; response to a command that uses a message
; sequence number greater than the number of
; messages in the selected mailbox. This
; includes "*" if the selected mailbox is empty.
seq-last-command = "$" seq-range = seq-number ":" seq-number
; two seq-number values and all values between
; these two regardless of order.
; Example: 2:4 and 4:2 are equivalent and
; indicate values 2, 3, and 4.
; Example: a unique identifier sequence range of
; 3291:* includes the UID of the last message in
; the mailbox, even if that value is less than
; 3291.
status = "STATUS" SP mailbox SP sequence-set = (seq-number / seq-range) ["," sequence-set]
"(" status-att *(SP status-att) ")" ; set of seq-number values, regardless of order.
; Servers MAY coalesce overlaps and/or execute
; the sequence in any order.
; Example: a message sequence number set of
; 2,4:7,9,12:* for a mailbox with 15 messages is
; equivalent to 2,4,5,6,7,9,12,13,14,15
; Example: a message sequence number set of
; *:4,5:7 for a mailbox with 10 messages is
; equivalent to 10,9,8,7,6,5,4,5,6,7 and MAY
; be reordered and overlap coalesced to be
; 4,5,6,7,8,9,10.
status-att = "MESSAGES" / "UIDNEXT" / "UIDVALIDITY" / sequence-set =/ seq-last-command
"UNSEEN" / "DELETED" / "SIZE" ; Allow for "result of the last command"
; indicator.
status-att-val = ("MESSAGES" SP number) / seq-last-command = "$"
("UIDNEXT" SP nz-number) /
("UIDVALIDITY" SP nz-number) /
("UNSEEN" SP number) /
("DELETED" SP number) /
("SIZE" SP number64)
; Extensions to the STATUS responses
; should extend this production.
; Extensions should use the generic
; syntax defined by tagged-ext.
status-att-list = status-att-val *(SP status-att-val) status = "STATUS" SP mailbox SP
"(" status-att *(SP status-att) ")"
status-option = "STATUS" SP "(" status-att *(SP status-att) ")" status-att = "MESSAGES" / "UIDNEXT" / "UIDVALIDITY" /
; This ABNF production complies with "UNSEEN" / "DELETED" / "SIZE"
; <option-extension> syntax.
store = "STORE" SP sequence-set SP store-att-flags status-att-val = ("MESSAGES" SP number) /
("UIDNEXT" SP nz-number) /
("UIDVALIDITY" SP nz-number) /
("UNSEEN" SP number) /
("DELETED" SP number) /
("SIZE" SP number64)
; Extensions to the STATUS responses
; should extend this production.
; Extensions should use the generic
; syntax defined by tagged-ext.
store-att-flags = (["+" / "-"] "FLAGS" [".SILENT"]) SP status-att-list = status-att-val *(SP status-att-val)
(flag-list / (flag *(SP flag)))
string = quoted / literal status-option = "STATUS" SP "(" status-att *(SP status-att) ")"
subscribe = "SUBSCRIBE" SP mailbox ; This ABNF production complies with
; <option-extension> syntax.
tag = 1*<any ASTRING-CHAR except "+"> store = "STORE" SP sequence-set SP store-att-flags
tag-string = astring store-att-flags = (["+" / "-"] "FLAGS" [".SILENT"]) SP
; <tag> represented as <astring> (flag-list / (flag *(SP flag)))
tagged-ext-label = tagged-label-fchar *tagged-label-char string = quoted / literal
; Is a valid RFC 3501 "atom".
tagged-label-fchar = ALPHA / "-" / "_" / "." subscribe = "SUBSCRIBE" SP mailbox
tagged-label-char = tagged-label-fchar / DIGIT / ":" tag = 1*<any ASTRING-CHAR except "+">
tagged-ext-comp = astring / tag-string = astring
tagged-ext-comp *(SP tagged-ext-comp) / ; <tag> represented as <astring>
"(" tagged-ext-comp ")"
; Extensions that follow this general
; syntax should use nstring instead of
; astring when appropriate in the context
; of the extension.
; Note that a message set or a "number"
; can always be represented as an "atom".
; An URL should be represented as
; a "quoted" string.
tagged-ext-simple = sequence-set / number / number64 tagged-ext-label = tagged-label-fchar *tagged-label-char
; Is a valid RFC 3501 "atom".
tagged-ext-val = tagged-ext-simple / tagged-label-fchar = ALPHA / "-" / "_" / "."
"(" [tagged-ext-comp] ")"
text = 1*(TEXT-CHAR / UTF8-2 / UTF8-3 / UTF8-4) tagged-label-char = tagged-label-fchar / DIGIT / ":"
; Non ASCII text can only be returned
; after ENABLE IMAP4rev2 command
TEXT-CHAR = <any CHAR except CR and LF> tagged-ext-comp = astring /
tagged-ext-comp *(SP tagged-ext-comp) /
"(" tagged-ext-comp ")"
; Extensions that follow this general
; syntax should use nstring instead of
; astring when appropriate in the context
; of the extension.
; Note that a message set or a "number"
; can always be represented as an "atom".
; A URL should be represented as
; a "quoted" string.
time = 2DIGIT ":" 2DIGIT ":" 2DIGIT tagged-ext-simple = sequence-set / number / number64
; Hours minutes seconds
uid = "UID" SP tagged-ext-val = tagged-ext-simple /
(copy / move / fetch / search / store / uid-expunge) "(" [tagged-ext-comp] ")"
; Unique identifiers used instead of message
; sequence numbers
uid-expunge = "EXPUNGE" SP sequence-set text = 1*(TEXT-CHAR / UTF8-2 / UTF8-3 / UTF8-4)
; Unique identifiers used instead of message ; Non-ASCII text can only be returned
; sequence numbers ; after ENABLE IMAP4rev2 command
uid-set = (uniqueid / uid-range) *("," uid-set) TEXT-CHAR = <any CHAR except CR and LF>
uid-range = (uniqueid ":" uniqueid) time = 2DIGIT ":" 2DIGIT ":" 2DIGIT
; two uniqueid values and all values ; Hours minutes seconds
; between these two regards of order.
; Example: 2:4 and 4:2 are equivalent.
uniqueid = nz-number uid = "UID" SP
; Strictly ascending (copy / move / fetch / search / store /
uid-expunge)
; Unique identifiers used instead of message
; sequence numbers
unsubscribe = "UNSUBSCRIBE" SP mailbox uid-expunge = "EXPUNGE" SP sequence-set
; Unique identifiers used instead of message
; sequence numbers
userid = astring uid-set = (uniqueid / uid-range) *("," uid-set)
UTF8-CHAR = <Defined in Section 4 of RFC 3629> uid-range = (uniqueid ":" uniqueid)
; two uniqueid values and all values
; between these two regardless of order.
; Example: 2:4 and 4:2 are equivalent.
UTF8-2 = <Defined in Section 4 of RFC 3629> uniqueid = nz-number
; Strictly ascending
UTF8-3 = <Defined in Section 4 of RFC 3629> unsubscribe = "UNSUBSCRIBE" SP mailbox
UTF8-4 = <Defined in Section 4 of RFC 3629> userid = astring
vendor-token = "vendor." name-component UTF8-CHAR = <Defined in Section 4 of RFC 3629>
; Definition copied from RFC 2244.
; MUST be registered with IANA
zone = ("+" / "-") 4DIGIT UTF8-2 = <Defined in Section 4 of RFC 3629>
; Signed four-digit value of hhmm representing
; hours and minutes east of Greenwich (that is, UTF8-3 = <Defined in Section 4 of RFC 3629>
; the amount that the given time differs from
; Universal Time). Subtracting the timezone UTF8-4 = <Defined in Section 4 of RFC 3629>
; from the given time will give the UT form.
; The Universal Time zone is "+0000". vendor-token = "vendor." name-component
; Definition copied from RFC 2244.
; MUST be registered with IANA
zone = ("+" / "-") 4DIGIT
; Signed four-digit value of hhmm representing
; hours and minutes east of Greenwich (that is,
; the amount that the given time differs from
; Universal Time). Subtracting the timezone
; from the given time will give the UT form.
; The Universal Time zone is "+0000".
10. Author's Note 10. Author's Note
This document is a revision or rewrite of earlier documents, and This document is a revision or rewrite of earlier documents and
supercedes the protocol specification in those documents: RFC 3501, supercedes the protocol specification in those documents: [RFC3501],
RFC 2060, RFC 1730, unpublished IMAP2bis.TXT document, RFC 1176, and [RFC2060], [RFC1730], unpublished IMAP2bis.TXT document, [IMAP2], and
RFC 1064. [RFC1064].
11. Security Considerations 11. Security Considerations
IMAP4rev2 protocol transactions, including electronic mail data, are IMAP4rev2 protocol transactions, including electronic mail data, are
sent in the clear over the network exposing them to possible sent in the clear over the network, exposing them to possible
eavesdropping and manipulation unless protection is negotiated. This eavesdropping and manipulation unless protection is negotiated. This
can be accomplished either by the use of Implicit TLS port, STARTTLS can be accomplished by use of the Implicit TLS port, the STARTTLS
command, negotiated confidentiality protection in the AUTHENTICATE command, negotiated confidentiality protection in the AUTHENTICATE
command, or some other protection mechanism. command, or some other protection mechanism.
11.1. TLS related Security Considerations 11.1. TLS-Related Security Considerations
This section applies to both use of STARTTLS command and Implicit TLS This section applies to use of both the STARTTLS command and the
port. Implicit TLS port.
IMAP client and server implementations MUST comply with relevant TLS IMAP client and server implementations MUST comply with relevant TLS
recommendations from [RFC8314]. recommendations from [RFC8314]. If recommendations/requirements in
this document conflict with recommendations from [RFC8314], for
example in regards to TLS ciphersuites, recommendations from this
document take precedence.
Clients and servers MUST implement TLS 1.2 [TLS-1.2] or newer. Use Clients and servers MUST implement TLS 1.2 [TLS-1.2] or newer. Use
of TLS 1.3 [TLS-1.3] is RECOMMENDED. TLS 1.2 may be used only in of TLS 1.3 [TLS-1.3] is RECOMMENDED. TLS 1.2 may be used only in
cases where the other party has not yet implemented TLS 1.3. cases where the other party has not yet implemented TLS 1.3.
Additionally, when using TLS 1.2, IMAP implementations MUST implement Additionally, when using TLS 1.2, IMAP implementations MUST implement
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 cipher suite. This is the TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 cipher suite. This is
important as it assures that any two compliant implementations can be important as it ensures that any two compliant implementations can be
configured to interoperate. Other TLS cipher suites recommended in configured to interoperate. Other TLS cipher suites recommended in
RFC 7525 [RFC7525] are RECOMMENDED: RFC 7525 [RFC7525] are RECOMMENDED:
TLS_DHE_RSA_WITH_AES_128_GCM_SHA256, TLS_DHE_RSA_WITH_AES_128_GCM_SHA256,
TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 and TLS_DHE_RSA_WITH_AES_256_GCM_SHA384, and
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384. All other cipher suites are TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384. All other cipher suites are
OPTIONAL. Note that this is a change from section 2.1 of [IMAP-TLS]. OPTIONAL. Note that this is a change from Section 2.1 of [IMAP-TLS].
The list of mandatory-to-implement TLS 1.3 cipher suites is described The list of mandatory-to-implement TLS 1.3 cipher suites is described
in Section 9.1 of [TLS-1.3]. in Section 9.1 of [TLS-1.3].
During the TLS negotiation [TLS-1.3][TLS-1.2], the client MUST check During the TLS negotiation [TLS-1.3] [TLS-1.2], the client MUST check
its understanding of the server hostname against the server's its understanding of the server hostname against the server's
identity as presented in the server Certificate message, in order to identity as presented in the server Certificate message, in order to
prevent on-path attackers attempting to masquerade as the server. prevent on-path attackers attempting to masquerade as the server.
This procedure is described in [RFC7817]. This procedure is described in [RFC7817].
Both the client and server MUST check the result of the STARTTLS Both the client and server MUST check the result of the STARTTLS
command and subsequent TLS ([TLS-1.3][TLS-1.2]) negotiation to see command and subsequent TLS [TLS-1.3] [TLS-1.2] negotiation to see
whether acceptable authentication and/or privacy was achieved. whether acceptable authentication and/or privacy was achieved.
11.2. STARTTLS command versa use of Implicit TLS port 11.2. STARTTLS Command versus Use of Implicit TLS Port
For maximum backward compatibility the client MUST implement both TLS For maximum backward compatibility, the client MUST implement both
negotiation on implicit TLS port and TLS negotiation using STARTTLS TLS negotiation on an Implicit TLS port and TLS negotiation using the
command on cleartext port. STARTTLS command on a cleartext port.
The server MUST implement TLS negotiation on implicit TLS port. The The server MUST implement TLS negotiation on an Implicit TLS port.
server SHOULD also implement IMAP on cleartext port. If the server The server SHOULD also implement IMAP on a cleartext port. If the
listens on a cleartext port, it MUST allow STARTTLS command on it. server listens on a cleartext port, it MUST allow the STARTTLS
command on it.
Some site/firewall maintainers insist on TLS site-wide and prefer not Some site/firewall maintainers insist on TLS site-wide and prefer not
to rely on a configuration option in each higher-level protocol. For to rely on a configuration option in each higher-level protocol. For
this reason, IMAP4rev2 clients SHOULD try both ports 993 and 143 (and this reason, IMAP4rev2 clients SHOULD try both ports 993 and 143 (and
both IPv4 and IPv6) concurrently by default, unless overridden by both IPv4 and IPv6) concurrently by default, unless overridden by
either user configuration or DNS SRV records [RFC6186]. A good either user configuration or DNS SRV records [RFC6186]. A good
algorithm for implementing such concurrent connect is described in algorithm for implementing such concurrent connect is described in
[RFC8305]. [RFC8305].
11.3. Client handling of unsolicited responses not suitable for the 11.3. Client Handling of Unsolicited Responses Not Suitable for the
current connection state Current Connection State
Cleartext mail transmission (whether caused by firewall configuration Cleartext mail transmission (whether caused by firewall configuration
errors that result in TLS stripping or weak security policies in errors that result in TLS stripping or weak security policies in
email clients that choose not to negotiate TLS in the first place) email clients that choose not to negotiate TLS in the first place)
can enable injection of responses that can confuse or even cause can enable injection of responses that can confuse or even cause
crashes in email clients. The following measures are recommended to crashes in email clients. The following measures are recommended to
minimize damage from them. minimize damage from them.
See Section 7.1.4 for special security considerations related to * See Section 7.1.4 for special security considerations related to
PREAUTH response. the PREAUTH response.
Many server responses and response codes are only meaningful in * Many server responses and response codes are only meaningful in
authenticated or even selected state. However, nothing prevents a authenticated or even selected state. However, nothing prevents a
server (or an on-path attacker) from sending such invalid server (or an on-path attacker) from sending such invalid
responses in cleartext before STARTTLS/AUTHENTICATE commands are responses in cleartext before STARTTLS/AUTHENTICATE commands are
issued. Before authentication clients SHOULD ignore any responses issued. Before authentication, clients SHOULD ignore any
other than CAPABILITY and server status responses (Section 7.1), responses other than CAPABILITY and server status responses
as well as any response codes other than CAPABILITY. (In (Section 7.1), as well as any response codes other than
particular, some email clients are known to incorrectly process CAPABILITY. (In particular, some email clients are known to
LIST responses received before authentication.) Clients SHOULD incorrectly process LIST responses received before authentication,
or FETCH responses when no mailbox is selected.) Clients SHOULD
ignore the ALERT response code until after TLS (whether using ignore the ALERT response code until after TLS (whether using
STARTTLS or TLS negotiation on implicit TLS port) or SASL security STARTTLS or TLS negotiation on an Implicit TLS port) or a SASL
layer with confidentiality protection has been successfully security layer with confidentiality protection has been
negotiated. Unless explicitly allowed by an IMAP extension, when successfully negotiated. Unless explicitly allowed by an IMAP
not in selected state clients MUST ignore responses/response codes extension, when not in selected state, clients MUST ignore
related to message and mailbox status such as FLAGS, EXIST, responses / response codes related to message and mailbox status
EXPUNGE and FETCH. such as FLAGS, EXIST, EXPUNGE, and FETCH.
11.4. COPYUID and APPENDUID response codes 11.4. COPYUID and APPENDUID Response Codes
The COPYUID and APPENDUID response codes return information about the The COPYUID and APPENDUID response codes return information about the
mailbox, which may be considered sensitive if the mailbox has mailbox, which may be considered sensitive if the mailbox has
permissions set that permit the client to COPY or APPEND to the permissions set that permit the client to COPY or APPEND to the
mailbox, but not SELECT or EXAMINE it. mailbox, but not SELECT or EXAMINE it.
Consequently, these response codes SHOULD NOT be issued if the client Consequently, these response codes SHOULD NOT be issued if the client
does not have access to SELECT or EXAMINE the mailbox. does not have access to SELECT or EXAMINE the mailbox.
11.5. LIST command and Other Users' namespace 11.5. LIST Command and Other Users' Namespace
In response to a LIST command containing an argument of the Other In response to a LIST command containing an argument of the Other
Users' Namespace prefix, a server SHOULD NOT list users that have not Users' Namespace prefix, a server MUST NOT list users that have not
granted list access to their personal mailboxes to the currently granted list access to their personal mailboxes to the currently
authenticated user. Providing such a list, could compromise security authenticated user. Providing such a list could compromise security
by potentially disclosing confidential information of who is located by potentially disclosing confidential information of who is located
on the server, or providing a starting point of a list of user on the server or providing a starting point for a list of user
accounts to attack. accounts to attack.
11.6. Use of MD5 11.6. Use of MD5
The BODYSTRUCTURE FETCH Data item can contain a the MD5 digest of the The BODYSTRUCTURE FETCH data item can contain the MD5 digest of the
message body in the "body MD5" field (body-fld-md5 ABNF production). message body in the "body MD5" field (body-fld-md5 ABNF production).
While MD5 is no longer considered a secure cryptographic hash While MD5 is no longer considered a secure cryptographic hash
[RFC6151], this field is used solely to expose the value of the [RFC6151], this field is used solely to expose the value of the
Content-MD5 header field (if present in the original message), which Content-MD5 header field (if present in the original message), which
is just a message integrity check and is not used for cryptographic is just a message integrity check and is not used for cryptographic
purposes. Also note that other mechanisms that provide message purposes. Also note that other mechanisms that provide message
integrity checks were defined since RFC 1864 was published and are integrity checks were defined since RFC 1864 [MD5] was published and
now more commonly used than Content-MD5. Two such mechanisms are are now more commonly used than Content-MD5. Two such mechanisms are
DKIM-Signature [RFC6376] header field and S/MIME signing the DKIM-Signature header field [RFC6376] and S/MIME signing
[RFC8550][RFC8550]. [RFC8550] [RFC8551].
11.7. Other Security Considerations 11.7. Other Security Considerations
A server error message for an AUTHENTICATE command which fails due to A server error message for an AUTHENTICATE command that fails due to
invalid credentials SHOULD NOT detail why the credentials are invalid credentials SHOULD NOT detail why the credentials are
invalid. invalid.
Use of the LOGIN command sends passwords in the clear. This can be Use of the LOGIN command sends passwords in the clear. This can be
avoided by using the AUTHENTICATE command with a [SASL] mechanism avoided by using the AUTHENTICATE command with a [SASL] mechanism
that does not use plaintext passwords, by first negotiating that does not use plaintext passwords, by first negotiating
encryption via STARTTLS or some other protection mechanism. encryption via STARTTLS or some other protection mechanism.
A server implementation MUST implement a configuration that, at the A server implementation MUST implement a configuration that, at the
time of authentication, requires: time of authentication, requires:
(1) The STARTTLS command has been negotiated or TLS negotiated on
implicit TLS port. 1. The STARTTLS command has been negotiated or TLS negotiated on an
OR Implicit TLS port
(2) Some other mechanism that protects the session from password OR
snooping has been provided. 2. Some other mechanism that protects the session from password
OR snooping has been provided
(3) The following measures are in place: OR
(a) The LOGINDISABLED capability is advertised, and [SASL] mechanisms 3. The following measures are in place:
(such as PLAIN) using plaintext passwords are NOT advertised in the a) The LOGINDISABLED capability is advertised, and [SASL]
CAPABILITY list. mechanisms (such as PLAIN) using plaintext passwords are NOT
AND advertised in the CAPABILITY list.
(b) The LOGIN command returns an error even if the password is AND
correct. b) The LOGIN command returns an error even if the password is
AND correct
(c) The AUTHENTICATE command returns an error with all [SASL] AND
mechanisms that use plaintext passwords, even if the password is c) The AUTHENTICATE command returns an error with all [SASL]
correct. mechanisms that use plaintext passwords, even if the password
is correct.
A server error message for a failing LOGIN command SHOULD NOT specify A server error message for a failing LOGIN command SHOULD NOT specify
that the user name, as opposed to the password, is invalid. that the user name, as opposed to the password, is invalid.
A server SHOULD have mechanisms in place to limit or delay failed A server SHOULD have mechanisms in place to limit or delay failed
AUTHENTICATE/LOGIN attempts. AUTHENTICATE/LOGIN attempts.
A server SHOULD report any authentication failure and analyze such A server SHOULD report any authentication failure and analyze such
authentication failure attempt with regard to a password brute force authentication failure attempts with regard to a password brute-force
attack as well as a password spraying attack. Accounts with attack as well as a password spraying attack [NCSC]. Accounts with
passwords that match well known passwords from spraying attacks MUST passwords that match well-known passwords from spraying attacks MUST
be blocked and users associated with such accounts must be requested be blocked, and users associated with such accounts must be requested
to change their passwords. Only password with significant strength to change their passwords. Only a password with significant strength
SHOULD be accepted. SHOULD be accepted.
Additional security considerations are discussed in the section Additional security considerations are discussed in the sections that
discussing the AUTHENTICATE (see Section 6.2.2) and LOGIN (see define the AUTHENTICATE and LOGIN commands (see Sections 6.2.2 and
Section 6.2.3) commands. 6.2.3, respectively).
12. IANA Considerations 12. IANA Considerations
IANA is requested to update "Service Names and Transport Protocol IANA has updated the "Service Names and Transport Protocol Port
Port Numbers" registry as follows: Numbers" registry as follows:
1. Registration for TCP port 143 and the corresponding "imap" 1. Registration for TCP port 143 and the corresponding "imap"
service name should be updated to point to this document and RFC service name have been updated to point to this document and
3501. [RFC3501].
2. Registration for TCP port 993 and the corresponding "imaps" 2. Registration for TCP port 993 and the corresponding "imaps"
service name should be updated to point to this document, RFC service name have been updated to point to this document,
8314 and RFC 3501. [RFC8314], and [RFC3501].
3. Both UDP port 143 and UDP port 993 should be marked as "Reserved" 3. UDP ports 143 and 993 have both been marked as "Reserved" in the
in the registry. registry.
Additional IANA actions are specified in subsection of this section. Additional IANA actions are specified in the subsections that follow.
12.1. Updates to IMAP4 Capabilities registry 12.1. Updates to IMAP Capabilities Registry
IMAP4 capabilities are registered by publishing a standards track or IMAP4 capabilities are registered by publishing a Standards Track or
IESG approved informational or experimental RFC. The registry is IESG-approved Informational or Experimental RFC. The registry is
currently located at: https://www.iana.org/assignments/ currently located at: <https://www.iana.org/assignments/
imap4-capabilities imap4-capabilities>
As this specification revises the AUTH= prefix, STARTTLS and As this specification revises the AUTH= prefix, STARTTLS, and
LOGINDISABLED extensions, IANA is requested to update registry LOGINDISABLED extensions, IANA has updated registry entries for these
entries for these 3 extensions to point to this document and RFC 3 extensions to point to this document and [RFC3501].
3501.
12.2. GSSAPI/SASL service name 12.2. GSSAPI/SASL Service Name
GSSAPI/Kerberos/SASL service names are registered by publishing a GSSAPI/Kerberos/SASL service names are registered by publishing a
standards track or IESG approved experimental RFC. The registry is Standards Track or IESG-approved Experimental RFC. The registry is
currently located at: https://www.iana.org/assignments/gssapi- currently located at: <https://www.iana.org/assignments/gssapi-
service-names service-names>
IANA is requested to update the "imap" service name previously IANA has updated the "imap" service name previously registered in
registered in RFC 3501, to point to both this document and RFC 3501. [RFC3501] to point to both this document and [RFC3501].
12.3. LIST Selection Options, LIST Return Options, LIST extended data 12.3. LIST Selection Options, LIST Return Options, and LIST Extended
items Data Items
[RFC5258] specifies IANA registration procedures for LIST Selection [RFC5258] specifies IANA registration procedures for LIST selection
Options, LIST Return Options, LIST extended data items. This options, LIST return options, and LIST extended data items. This
document doesn't change these registration procedures. In particular document doesn't change these registration procedures. In
LIST selection options (Section 6.3.9.1) and LIST return options particular, LIST selection options (Section 6.3.9.1) and LIST return
(Section 6.3.9.2) are registered using the procedure specified in options (Section 6.3.9.2) are registered using the procedure
Section 9 of [RFC5258] (and using the registration template from specified in Section 9 of [RFC5258] (and using the registration
Section 9.3 of [RFC5258]). LIST Extended Data Items are registered template from Section 9.3 of [RFC5258]). LIST extended data items
using the registration template from Section 9.6 of [RFC5258]). are registered using the registration template from Section 9.6 of
[RFC5258]).
IANA is requested to add a reference to [RFCXXXX] for the "OLDNAME" IANA has added a reference to RFC 9051 for the "OLDNAME" LIST-
LIST-EXTENDED extended data item entry. This is in addition to the EXTENDED extended data item entry. This is in addition to the
existing reference to [RFC5465]. existing reference to [RFC5465].
12.4. IMAP Mailbox Name Attributes and IMAP Response Codes 12.4. IMAP Mailbox Name Attributes and IMAP Response Codes
IANA is requested to update the "IMAP Mailbox Name Attributes" IANA has updated the "IMAP Mailbox Name Attributes" registry to point
registry to point to this document in addition to RFC 3501. to this document in addition to [RFC3501].
IANA is requested to update the "IMAP Response Codes" registry to IANA has updated the "IMAP Response Codes" registry to point to this
point to this document in addition to RFC 3501. document in addition to [RFC3501].
13. References 13. References
13.1. Normative References
[RFC4752] Melnikov, A., Ed., "The Kerberos V5 ("GSSAPI") Simple 13.1. Normative References
Authentication and Security Layer (SASL) Mechanism",
RFC 4752, DOI 10.17487/RFC4752, November 2006,
<https://www.rfc-editor.org/info/rfc4752>.
[RFC5258] Leiba, B. and A. Melnikov, "Internet Message Access
Protocol version 4 - LIST Command Extensions", RFC 5258,
DOI 10.17487/RFC5258, June 2008,
<https://www.rfc-editor.org/info/rfc5258>.
[RFC5788] Melnikov, A. and D. Cridland, "IMAP4 Keyword Registry",
RFC 5788, DOI 10.17487/RFC5788, March 2010,
<https://www.rfc-editor.org/info/rfc5788>.
[ABNF] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax [ABNF] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, January 2008, Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
<https://www.rfc-editor.org/info/rfc5234>. <https://www.rfc-editor.org/info/rfc5234>.
[CHARSET] Freed, N. and J. Postel, "IANA Charset Registration [BCP178] Saint-Andre, P., Crocker, D., and M. Nottingham,
Procedures", BCP 19, RFC 2978, October 2000, "Deprecating the "X-" Prefix and Similar Constructs in
<https://www.rfc-editor.org/info/rfc2978>. Application Protocols", BCP 178, RFC 6648, June 2012.
[SCRAM-SHA-256] <https://www.rfc-editor.org/info/bcp178>
Hansen, T., "SCRAM-SHA-256 and SCRAM-SHA-256-PLUS Simple
Authentication and Security Layer (SASL) Mechanisms", [CHARSET] Freed, N. and J. Postel, "IANA Charset Registration
RFC 7677, DOI 10.17487/RFC7677, November 2015, Procedures", BCP 19, RFC 2978, DOI 10.17487/RFC2978,
<https://www.rfc-editor.org/info/rfc7677>. October 2000, <https://www.rfc-editor.org/info/rfc2978>.
[DISPOSITION] [DISPOSITION]
Troost, R., Dorner, S., and K. Moore, Ed., "Communicating Troost, R., Dorner, S., and K. Moore, Ed., "Communicating
Presentation Information in Internet Messages: The Presentation Information in Internet Messages: The
Content-Disposition Header Field", RFC 2183, August 1997, Content-Disposition Header Field", RFC 2183,
DOI 10.17487/RFC2183, August 1997,
<https://www.rfc-editor.org/info/rfc2183>. <https://www.rfc-editor.org/info/rfc2183>.
[PLAIN] Zeilenga, K., Ed., "The PLAIN Simple Authentication and [I18N-HDRS]
Security Layer (SASL) Mechanism", RFC 4616, August 2006, Yang, A., Steele, S., and N. Freed, "Internationalized
<https://www.rfc-editor.org/info/rfc4616>. Email Headers", RFC 6532, DOI 10.17487/RFC6532, February
2012, <https://www.rfc-editor.org/info/rfc6532>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [IMAP-IMPLEMENTATION]
Requirement Levels", BCP 14, RFC 2119, Leiba, B., "IMAP4 Implementation Recommendations",
DOI 10.17487/RFC2119, March 1997, RFC 2683, DOI 10.17487/RFC2683, September 1999,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2683>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [IMAP-MULTIACCESS]
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, Gahrns, M., "IMAP4 Multi-Accessed Mailbox Practice",
May 2017, <https://www.rfc-editor.org/info/rfc8174>. RFC 2180, DOI 10.17487/RFC2180, July 1997,
<https://www.rfc-editor.org/info/rfc2180>.
[LANGUAGE-TAGS] [LANGUAGE-TAGS]
Alvestrand, H., "Content Language Headers", RFC 3282, May Alvestrand, H., "Content Language Headers", RFC 3282,
2002, <https://www.rfc-editor.org/info/rfc3282>. DOI 10.17487/RFC3282, May 2002,
<https://www.rfc-editor.org/info/rfc3282>.
[LOCATION] [LOCATION] Palme, J., Hopmann, A., and N. Shelness, "MIME
Palme, J., Hopmann, A., and N. Shelness, "MIME
Encapsulation of Aggregate Documents, such as HTML Encapsulation of Aggregate Documents, such as HTML
(MHTML)", RFC 2557, March 1999, (MHTML)", RFC 2557, DOI 10.17487/RFC2557, March 1999,
<https://www.rfc-editor.org/info/rfc2557>. <https://www.rfc-editor.org/info/rfc2557>.
[MD5] Myers, J. and M. Rose, "The Content-MD5 Header Field", [MD5] Myers, J. and M. Rose, "The Content-MD5 Header Field",
RFC 1864, October 1995, RFC 1864, DOI 10.17487/RFC1864, October 1995,
<https://www.rfc-editor.org/info/rfc1864>. <https://www.rfc-editor.org/info/rfc1864>.
[MIME-HDRS] [MIME-HDRS]
Moore, K., "MIME (Multipurpose Internet Mail Extensions) Moore, K., "MIME (Multipurpose Internet Mail Extensions)
Part Three: Message Header Extensions for Non-ASCII Text", Part Three: Message Header Extensions for Non-ASCII Text",
RFC 2047, November 1996, RFC 2047, DOI 10.17487/RFC2047, November 1996,
<https://www.rfc-editor.org/info/rfc2047>. <https://www.rfc-editor.org/info/rfc2047>.
[MIME-IMB] [MIME-IMB] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message Extensions (MIME) Part One: Format of Internet Message
Bodies", RFC 2045, November 1996, Bodies", RFC 2045, DOI 10.17487/RFC2045, November 1996,
<https://www.rfc-editor.org/info/rfc2045>. <https://www.rfc-editor.org/info/rfc2045>.
[MIME-IMT] [MIME-IMT] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Two: Media Types", RFC 2046, Extensions (MIME) Part Two: Media Types", RFC 2046,
November 1996, <https://www.rfc-editor.org/info/rfc2046>. DOI 10.17487/RFC2046, November 1996,
<https://www.rfc-editor.org/info/rfc2046>.
[RFC2231] Freed, N. and K. Moore, "MIME Parameter Value and Encoded
Word Extensions: Character Sets, Languages, and
Continuations", RFC 2231, DOI 10.17487/RFC2231, November
1997, <https://www.rfc-editor.org/info/rfc2231>.
[RFC-5322]
Resnick, P., Ed., "Internet Message Format", RFC 5322,
October 2008, <https://www.rfc-editor.org/info/rfc5322>.
[SASL] Melnikov, A., Ed. and K. Zeilenga, Ed., "Simple
Authentication and Security Layer (SASL)", RFC 4422, June
2006, <https://www.rfc-editor.org/info/rfc4422>.
[TLS-1.2] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008,
<https://www.rfc-editor.org/info/rfc5246>.
[TLS-1.3] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
[UTF-7] Goldsmith, D. and M. Davis, "UTF-7 A Mail-Safe
Transformation Format of Unicode", RFC 2152, May 1997,
<https://www.rfc-editor.org/info/rfc2152>.
[UTF-8] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November
2003, <https://www.rfc-editor.org/info/rfc3629>.
[MULTIAPPEND] [MULTIAPPEND]
Crispin, M., "Internet Message Access Protocol (IMAP) - Crispin, M., "Internet Message Access Protocol (IMAP) -
MULTIAPPEND Extension", RFC 3502, March 2003, MULTIAPPEND Extension", RFC 3502, DOI 10.17487/RFC3502,
<https://www.rfc-editor.org/info/rfc3502>. March 2003, <https://www.rfc-editor.org/info/rfc3502>.
[NET-UNICODE] [NET-UNICODE]
Klensin, J. and M. Padlipsky, "Unicode Format for Network Klensin, J. and M. Padlipsky, "Unicode Format for Network
Interchange", RFC 5198, DOI 10.17487/RFC5198, March 2008, Interchange", RFC 5198, DOI 10.17487/RFC5198, March 2008,
<https://www.rfc-editor.org/info/rfc5198>. <https://www.rfc-editor.org/info/rfc5198>.
[I18N-HDRS] [PLAIN] Zeilenga, K., Ed., "The PLAIN Simple Authentication and
Yang, A., Steele, S., and N. Freed, "Internationalized Security Layer (SASL) Mechanism", RFC 4616,
Email Headers", RFC 6532, DOI 10.17487/RFC6532, February DOI 10.17487/RFC4616, August 2006,
2012, <https://www.rfc-editor.org/info/rfc6532>. <https://www.rfc-editor.org/info/rfc4616>.
[RFC2077] Nelson, S., Parks, C., and , "The Model Primary Content
Type for Multipurpose Internet Mail Extensions", RFC 2077,
DOI 10.17487/RFC2077, January 1997,
<https://www.rfc-editor.org/info/rfc2077>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2231] Freed, N. and K. Moore, "MIME Parameter Value and Encoded
Word Extensions: Character Sets, Languages, and
Continuations", RFC 2231, DOI 10.17487/RFC2231, November
1997, <https://www.rfc-editor.org/info/rfc2231>.
[RFC3503] Melnikov, A., "Message Disposition Notification (MDN) [RFC3503] Melnikov, A., "Message Disposition Notification (MDN)
profile for Internet Message Access Protocol (IMAP)", profile for Internet Message Access Protocol (IMAP)",
RFC 3503, DOI 10.17487/RFC3503, March 2003, RFC 3503, DOI 10.17487/RFC3503, March 2003,
<https://www.rfc-editor.org/info/rfc3503>. <https://www.rfc-editor.org/info/rfc3503>.
[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006, Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
<https://www.rfc-editor.org/info/rfc4648>. <https://www.rfc-editor.org/info/rfc4648>.
[RFC4752] Melnikov, A., Ed., "The Kerberos V5 ("GSSAPI") Simple
Authentication and Security Layer (SASL) Mechanism",
RFC 4752, DOI 10.17487/RFC4752, November 2006,
<https://www.rfc-editor.org/info/rfc4752>.
[RFC5258] Leiba, B. and A. Melnikov, "Internet Message Access
Protocol version 4 - LIST Command Extensions", RFC 5258,
DOI 10.17487/RFC5258, June 2008,
<https://www.rfc-editor.org/info/rfc5258>.
[RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322,
DOI 10.17487/RFC5322, October 2008,
<https://www.rfc-editor.org/info/rfc5322>.
[RFC5788] Melnikov, A. and D. Cridland, "IMAP4 Keyword Registry",
RFC 5788, DOI 10.17487/RFC5788, March 2010,
<https://www.rfc-editor.org/info/rfc5788>.
[RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre, [RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre,
"Recommendations for Secure Use of Transport Layer "Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May (DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May
2015, <https://www.rfc-editor.org/info/rfc7525>. 2015, <https://www.rfc-editor.org/info/rfc7525>.
[RFC7817] Melnikov, A., "Updated Transport Layer Security (TLS) [RFC7817] Melnikov, A., "Updated Transport Layer Security (TLS)
Server Identity Check Procedure for Email-Related Server Identity Check Procedure for Email-Related
Protocols", RFC 7817, DOI 10.17487/RFC7817, March 2016, Protocols", RFC 7817, DOI 10.17487/RFC7817, March 2016,
<https://www.rfc-editor.org/info/rfc7817>. <https://www.rfc-editor.org/info/rfc7817>.
[RFC8081] Lilley, C., "The "font" Top-Level Media Type", RFC 8081,
DOI 10.17487/RFC8081, February 2017,
<https://www.rfc-editor.org/info/rfc8081>.
[RFC8098] Hansen, T., Ed. and A. Melnikov, Ed., "Message Disposition [RFC8098] Hansen, T., Ed. and A. Melnikov, Ed., "Message Disposition
Notification", STD 85, RFC 8098, DOI 10.17487/RFC8098, Notification", STD 85, RFC 8098, DOI 10.17487/RFC8098,
February 2017, <https://www.rfc-editor.org/info/rfc8098>. February 2017, <https://www.rfc-editor.org/info/rfc8098>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8314] Moore, K. and C. Newman, "Cleartext Considered Obsolete: [RFC8314] Moore, K. and C. Newman, "Cleartext Considered Obsolete:
Use of Transport Layer Security (TLS) for Email Submission Use of Transport Layer Security (TLS) for Email Submission
and Access", RFC 8314, DOI 10.17487/RFC8314, January 2018, and Access", RFC 8314, DOI 10.17487/RFC8314, January 2018,
<https://www.rfc-editor.org/info/rfc8314>. <https://www.rfc-editor.org/info/rfc8314>.
[IMAP-IMPLEMENTATION] [SASL] Melnikov, A., Ed. and K. Zeilenga, Ed., "Simple
Leiba, B., "IMAP4 Implementation Recommendations", Authentication and Security Layer (SASL)", RFC 4422,
RFC 2683, September 1999, DOI 10.17487/RFC4422, June 2006,
<https://www.rfc-editor.org/info/rfc2683>. <https://www.rfc-editor.org/info/rfc4422>.
[IMAP-MULTIACCESS]
Gahrns, M., "IMAP4 Multi-Accessed Mailbox Practice",
RFC 2180, July 1997,
<https://www.rfc-editor.org/info/rfc2180>.
13.2. Informative References (related protocols)
[CERT-555316] [SCRAM-SHA-256]
CERT, "Vulnerability Note VU#555316: STARTTLS plaintext Hansen, T., "SCRAM-SHA-256 and SCRAM-SHA-256-PLUS Simple
command injection vulnerability", September 2011, Authentication and Security Layer (SASL) Mechanisms",
<https://www.kb.cert.org/vuls/id/555316>. RFC 7677, DOI 10.17487/RFC7677, November 2015,
<https://www.rfc-editor.org/info/rfc7677>.
[RFC6151] Turner, S. and L. Chen, "Updated Security Considerations [TLS-1.2] Dierks, T. and E. Rescorla, "The Transport Layer Security
for the MD5 Message-Digest and the HMAC-MD5 Algorithms", (TLS) Protocol Version 1.2", RFC 5246,
RFC 6151, DOI 10.17487/RFC6151, March 2011, DOI 10.17487/RFC5246, August 2008,
<https://www.rfc-editor.org/info/rfc6151>. <https://www.rfc-editor.org/info/rfc5246>.
[RFC2193] Gahrns, M., "IMAP4 Mailbox Referrals", RFC 2193, [TLS-1.3] Rescorla, E., "The Transport Layer Security (TLS) Protocol
DOI 10.17487/RFC2193, September 1997, Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc2193>. <https://www.rfc-editor.org/info/rfc8446>.
[RFC3348] Gahrns, M. and R. Cheng, "The Internet Message Action [UTF-7] Goldsmith, D. and M. Davis, "UTF-7 A Mail-Safe
Protocol (IMAP4) Child Mailbox Extension", RFC 3348, Transformation Format of Unicode", RFC 2152,
DOI 10.17487/RFC3348, July 2002, DOI 10.17487/RFC2152, May 1997,
<https://www.rfc-editor.org/info/rfc3348>. <https://www.rfc-editor.org/info/rfc2152>.
[RFC5256] Crispin, M. and K. Murchison, "Internet Message Access [UTF-8] Yergeau, F., "UTF-8, a transformation format of ISO
Protocol - SORT and THREAD Extensions", RFC 5256, 10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November
DOI 10.17487/RFC5256, June 2008, 2003, <https://www.rfc-editor.org/info/rfc3629>.
<https://www.rfc-editor.org/info/rfc5256>.
[RFC5465] Gulbrandsen, A., King, C., and A. Melnikov, "The IMAP 13.2. Informative References
NOTIFY Extension", RFC 5465, DOI 10.17487/RFC5465,
February 2009, <https://www.rfc-editor.org/info/rfc5465>.
[RFC6186] Daboo, C., "Use of SRV Records for Locating Email 13.2.1. Related Protocols
Submission/Access Services", RFC 6186,
DOI 10.17487/RFC6186, March 2011,
<https://www.rfc-editor.org/info/rfc6186>.
[RFC7162] Melnikov, A. and D. Cridland, "IMAP Extensions: Quick Flag [ANONYMOUS]
Changes Resynchronization (CONDSTORE) and Quick Mailbox Zeilenga, K., "Anonymous Simple Authentication and
Resynchronization (QRESYNC)", RFC 7162, Security Layer (SASL) Mechanism", RFC 4505,
DOI 10.17487/RFC7162, May 2014, DOI 10.17487/RFC4505, June 2006,
<https://www.rfc-editor.org/info/rfc7162>. <https://www.rfc-editor.org/info/rfc4505>.
[RFC7888] Melnikov, A., Ed., "IMAP4 Non-synchronizing Literals", [CERT-555316]
RFC 7888, DOI 10.17487/RFC7888, May 2016, Carnegie Mellon University, "STARTTLS plaintext command
<https://www.rfc-editor.org/info/rfc7888>. injection vulnerability", Software Engineering Institute,
CERT Coordination Center, Vulnerability Note VU#555316,
September 2011, <https://www.kb.cert.org/vuls/id/555316>.
[RFC8474] Gondwana, B., Ed., "IMAP Extension for Object [CHARSET-REG]
Identifiers", RFC 8474, DOI 10.17487/RFC8474, September IANA, "Character Set Registrations",
2018, <https://www.rfc-editor.org/info/rfc8474>. <https://www.iana.org/assignments/charset-reg/>.
[IMAP-DISC] [IMAP-DISC]
Melnikov, A., Ed., "Synchronization Operations for Melnikov, A., Ed., "Synchronization Operations for
Disconnected IMAP4 Clients", RFC 4549, June 2006, Disconnected IMAP4 Clients", RFC 4549,
DOI 10.17487/RFC4549, June 2006,
<https://www.rfc-editor.org/info/rfc4549>. <https://www.rfc-editor.org/info/rfc4549>.
[IMAP-I18N] [IMAP-I18N]
Newman, C., Gulbrandsen, A., and A. Melnikov, "Internet Newman, C., Gulbrandsen, A., and A. Melnikov, "Internet
Message Access Protocol Internationalization", RFC 5255, Message Access Protocol Internationalization", RFC 5255,
DOI 10.17487/RFC5255, June 2008, DOI 10.17487/RFC5255, June 2008,
<https://www.rfc-editor.org/info/rfc5255>. <https://www.rfc-editor.org/info/rfc5255>.
[IMAP-KEYWORDS-REG]
IANA, "IMAP and JMAP Keywords",
<https://www.iana.org/assignments/imap-jmap-keywords/>.
[IMAP-MAILBOX-NAME-ATTRS-REG]
IANA, "IMAP Mailbox Name Attributes",
<https://www.iana.org/assignments/imap-mailbox-name-
attributes/>.
[IMAP-MODEL] [IMAP-MODEL]
Crispin, M., "Distributed Electronic Mail Models in Crispin, M., "Distributed Electronic Mail Models in
IMAP4", RFC 1733, December 1994, IMAP4", RFC 1733, DOI 10.17487/RFC1733, December 1994,
<https://www.rfc-editor.org/info/rfc1733>. <https://www.rfc-editor.org/info/rfc1733>.
[IMAP-URL] Melnikov, A., Ed. and C. Newman, "IMAP URL Scheme",
RFC 5092, DOI 10.17487/RFC5092, November 2007,
<https://www.rfc-editor.org/info/rfc5092>.
[IMAP-UTF-8] [IMAP-UTF-8]
Resnick, P., Ed., Newman, C., Ed., and S. Shen, Ed., "IMAP Resnick, P., Ed., Newman, C., Ed., and S. Shen, Ed., "IMAP
Support for UTF-8", RFC 6855, DOI 10.17487/RFC6855, March Support for UTF-8", RFC 6855, DOI 10.17487/RFC6855, March
2013, <https://www.rfc-editor.org/info/rfc6855>. 2013, <https://www.rfc-editor.org/info/rfc6855>.
[ANONYMOUS] [NCSC] NCSC, "Spray you, spray me: defending against password
Zeilenga, K., "Anonymous Simple Authentication and spraying attacks", May 2018, <https://www.ncsc.gov.uk/
Security Layer (SASL) Mechanism", RFC 4505, June 2006, blog-post/spray-you-spray-me-defending-against-password-
<https://www.rfc-editor.org/info/rfc4505>. spraying-attacks>.
[SMTP] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321, [RFC2087] Myers, J., "IMAP4 QUOTA extension", RFC 2087,
October 2008, <https://www.rfc-editor.org/info/rfc5321>. DOI 10.17487/RFC2087, January 1997,
<https://www.rfc-editor.org/info/rfc2087>.
[RFC2177] Leiba, B., "IMAP4 IDLE command", RFC 2177,
DOI 10.17487/RFC2177, June 1997,
<https://www.rfc-editor.org/info/rfc2177>.
[RFC2193] Gahrns, M., "IMAP4 Mailbox Referrals", RFC 2193,
DOI 10.17487/RFC2193, September 1997,
<https://www.rfc-editor.org/info/rfc2193>.
[RFC2342] Gahrns, M. and C. Newman, "IMAP4 Namespace", RFC 2342,
DOI 10.17487/RFC2342, May 1998,
<https://www.rfc-editor.org/info/rfc2342>.
[RFC3348] Gahrns, M. and R. Cheng, "The Internet Message Action
Protocol (IMAP4) Child Mailbox Extension", RFC 3348,
DOI 10.17487/RFC3348, July 2002,
<https://www.rfc-editor.org/info/rfc3348>.
[RFC3516] Nerenberg, L., "IMAP4 Binary Content Extension", RFC 3516, [RFC3516] Nerenberg, L., "IMAP4 Binary Content Extension", RFC 3516,
DOI 10.17487/RFC3516, April 2003, DOI 10.17487/RFC3516, April 2003,
<https://www.rfc-editor.org/info/rfc3516>. <https://www.rfc-editor.org/info/rfc3516>.
[RFC3691] Melnikov, A., "Internet Message Access Protocol (IMAP)
UNSELECT command", RFC 3691, DOI 10.17487/RFC3691,
February 2004, <https://www.rfc-editor.org/info/rfc3691>.
[RFC4314] Melnikov, A., "IMAP4 Access Control List (ACL) Extension", [RFC4314] Melnikov, A., "IMAP4 Access Control List (ACL) Extension",
RFC 4314, December 2005, RFC 4314, DOI 10.17487/RFC4314, December 2005,
<https://www.rfc-editor.org/info/rfc4314>. <https://www.rfc-editor.org/info/rfc4314>.
[RFC2087] Myers, J., "IMAP4 QUOTA extension", RFC 2087, January [RFC4315] Crispin, M., "Internet Message Access Protocol (IMAP) -
1997, <https://www.rfc-editor.org/info/rfc2087>. UIDPLUS extension", RFC 4315, DOI 10.17487/RFC4315,
December 2005, <https://www.rfc-editor.org/info/rfc4315>.
[IMAP-URL] [RFC4466] Melnikov, A. and C. Daboo, "Collected Extensions to IMAP4
Melnikov, A., Ed. and C. Newman, "IMAP URL Scheme", ABNF", RFC 4466, DOI 10.17487/RFC4466, April 2006,
RFC 5092, DOI 10.17487/RFC5092, November 2007, <https://www.rfc-editor.org/info/rfc4466>.
<https://www.rfc-editor.org/info/rfc5092>.
[RFC8305] Schinazi, D. and T. Pauly, "Happy Eyeballs Version 2: [RFC4731] Melnikov, A. and D. Cridland, "IMAP4 Extension to SEARCH
Better Connectivity Using Concurrency", RFC 8305, Command for Controlling What Kind of Information Is
DOI 10.17487/RFC8305, December 2017, Returned", RFC 4731, DOI 10.17487/RFC4731, November 2006,
<https://www.rfc-editor.org/info/rfc8305>. <https://www.rfc-editor.org/info/rfc4731>.
[RFC4959] Siemborski, R. and A. Gulbrandsen, "IMAP Extension for
Simple Authentication and Security Layer (SASL) Initial
Client Response", RFC 4959, DOI 10.17487/RFC4959,
September 2007, <https://www.rfc-editor.org/info/rfc4959>.
[RFC5161] Gulbrandsen, A., Ed. and A. Melnikov, Ed., "The IMAP
ENABLE Extension", RFC 5161, DOI 10.17487/RFC5161, March
2008, <https://www.rfc-editor.org/info/rfc5161>.
[RFC5182] Melnikov, A., "IMAP Extension for Referencing the Last
SEARCH Result", RFC 5182, DOI 10.17487/RFC5182, March
2008, <https://www.rfc-editor.org/info/rfc5182>.
[RFC5256] Crispin, M. and K. Murchison, "Internet Message Access
Protocol - SORT and THREAD Extensions", RFC 5256,
DOI 10.17487/RFC5256, June 2008,
<https://www.rfc-editor.org/info/rfc5256>.
[RFC5465] Gulbrandsen, A., King, C., and A. Melnikov, "The IMAP
NOTIFY Extension", RFC 5465, DOI 10.17487/RFC5465,
February 2009, <https://www.rfc-editor.org/info/rfc5465>.
[RFC5530] Gulbrandsen, A., "IMAP Response Codes", RFC 5530,
DOI 10.17487/RFC5530, May 2009,
<https://www.rfc-editor.org/info/rfc5530>.
[RFC5819] Melnikov, A. and T. Sirainen, "IMAP4 Extension for
Returning STATUS Information in Extended LIST", RFC 5819,
DOI 10.17487/RFC5819, March 2010,
<https://www.rfc-editor.org/info/rfc5819>.
[RFC6151] Turner, S. and L. Chen, "Updated Security Considerations
for the MD5 Message-Digest and the HMAC-MD5 Algorithms",
RFC 6151, DOI 10.17487/RFC6151, March 2011,
<https://www.rfc-editor.org/info/rfc6151>.
[RFC6154] Leiba, B. and J. Nicolson, "IMAP LIST Extension for
Special-Use Mailboxes", RFC 6154, DOI 10.17487/RFC6154,
March 2011, <https://www.rfc-editor.org/info/rfc6154>.
[RFC6186] Daboo, C., "Use of SRV Records for Locating Email
Submission/Access Services", RFC 6186,
DOI 10.17487/RFC6186, March 2011,
<https://www.rfc-editor.org/info/rfc6186>.
[RFC6376] Crocker, D., Ed., Hansen, T., Ed., and M. Kucherawy, Ed., [RFC6376] Crocker, D., Ed., Hansen, T., Ed., and M. Kucherawy, Ed.,
"DomainKeys Identified Mail (DKIM) Signatures", STD 76, "DomainKeys Identified Mail (DKIM) Signatures", STD 76,
RFC 6376, DOI 10.17487/RFC6376, September 2011, RFC 6376, DOI 10.17487/RFC6376, September 2011,
<https://www.rfc-editor.org/info/rfc6376>. <https://www.rfc-editor.org/info/rfc6376>.
[RFC6409] Gellens, R. and J. Klensin, "Message Submission for Mail",
STD 72, RFC 6409, DOI 10.17487/RFC6409, November 2011,
<https://www.rfc-editor.org/info/rfc6409>.
[RFC6851] Gulbrandsen, A. and N. Freed, Ed., "Internet Message
Access Protocol (IMAP) - MOVE Extension", RFC 6851,
DOI 10.17487/RFC6851, January 2013,
<https://www.rfc-editor.org/info/rfc6851>.
[RFC7162] Melnikov, A. and D. Cridland, "IMAP Extensions: Quick Flag
Changes Resynchronization (CONDSTORE) and Quick Mailbox
Resynchronization (QRESYNC)", RFC 7162,
DOI 10.17487/RFC7162, May 2014,
<https://www.rfc-editor.org/info/rfc7162>.
[RFC7888] Melnikov, A., Ed., "IMAP4 Non-synchronizing Literals",
RFC 7888, DOI 10.17487/RFC7888, May 2016,
<https://www.rfc-editor.org/info/rfc7888>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC8305] Schinazi, D. and T. Pauly, "Happy Eyeballs Version 2:
Better Connectivity Using Concurrency", RFC 8305,
DOI 10.17487/RFC8305, December 2017,
<https://www.rfc-editor.org/info/rfc8305>.
[RFC8438] Bosch, S., "IMAP Extension for STATUS=SIZE", RFC 8438,
DOI 10.17487/RFC8438, August 2018,
<https://www.rfc-editor.org/info/rfc8438>.
[RFC8474] Gondwana, B., Ed., "IMAP Extension for Object
Identifiers", RFC 8474, DOI 10.17487/RFC8474, September
2018, <https://www.rfc-editor.org/info/rfc8474>.
[RFC8550] Schaad, J., Ramsdell, B., and S. Turner, "Secure/ [RFC8550] Schaad, J., Ramsdell, B., and S. Turner, "Secure/
Multipurpose Internet Mail Extensions (S/MIME) Version 4.0 Multipurpose Internet Mail Extensions (S/MIME) Version 4.0
Certificate Handling", RFC 8550, DOI 10.17487/RFC8550, Certificate Handling", RFC 8550, DOI 10.17487/RFC8550,
April 2019, <https://www.rfc-editor.org/info/rfc8550>. April 2019, <https://www.rfc-editor.org/info/rfc8550>.
[RFC8551] Schaad, J., Ramsdell, B., and S. Turner, "Secure/ [RFC8551] Schaad, J., Ramsdell, B., and S. Turner, "Secure/
Multipurpose Internet Mail Extensions (S/MIME) Version 4.0 Multipurpose Internet Mail Extensions (S/MIME) Version 4.0
Message Specification", RFC 8551, DOI 10.17487/RFC8551, Message Specification", RFC 8551, DOI 10.17487/RFC8551,
April 2019, <https://www.rfc-editor.org/info/rfc8551>. April 2019, <https://www.rfc-editor.org/info/rfc8551>.
[IMAP-KEYWORDS-REG] [SMTP] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
IANA, "IMAP and JMAP Keywords", December 2009, DOI 10.17487/RFC5321, October 2008,
<https://www.iana.org/assignments/imap-jmap-keywords/imap- <https://www.rfc-editor.org/info/rfc5321>.
jmap-keywords.xhtml>.
[IMAP-MAILBOX-NAME-ATTRS-REG]
IANA, "IMAP Mailbox Name Attributes", June 2018,
<https://www.iana.org/assignments/imap-mailbox-name-
attributes/imap-mailbox-name-attributes.xhtml>.
[CHARSET-REG]
IANA, "Character Set Registrations", May 2015,
<https://www.iana.org/assignments/charset-reg/charset-
reg.xhtml>.
13.3. Informative References (historical aspects of IMAP and related
protocols)
[RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION 13.2.2. Historical Aspects of IMAP and Related Protocols
4rev1", RFC 3501, DOI 10.17487/RFC3501, March 2003,
<https://www.rfc-editor.org/info/rfc3501>.
[IMAP-COMPAT] [IMAP-COMPAT]
Crispin, M., "IMAP4 Compatibility with IMAP2bis", Crispin, M., "IMAP4 Compatibility with IMAP2bis",
RFC 2061, December 1996, RFC 2061, DOI 10.17487/RFC2061, December 1996,
<https://www.rfc-editor.org/info/rfc2061>. <https://www.rfc-editor.org/info/rfc2061>.
[IMAP-HISTORICAL] [IMAP-HISTORICAL]
Crispin, M., "IMAP4 Compatibility with IMAP2 and Crispin, M., "IMAP4 Compatibility with IMAP2 and
IMAP2bis", RFC 1732, December 1994, IMAP2bis", RFC 1732, DOI 10.17487/RFC1732, December 1994,
<https://www.rfc-editor.org/info/rfc1732>. <https://www.rfc-editor.org/info/rfc1732>.
[IMAP2BIS]
Crispin, M., "INTERACTIVE MAIL ACCESS PROTOCOL - VERSION
2bis", draft-ietf-imap-imap2bis-02 (work in progress),
October 1993, <https://www.ietf.org/archive/id/draft-ietf-
imap-imap2bis-02.txt>.
[IMAP-OBSOLETE] [IMAP-OBSOLETE]
Crispin, M., "Internet Message Access Protocol - Obsolete Crispin, M., "Internet Message Access Protocol - Obsolete
Syntax", RFC 2062, December 1996, Syntax", RFC 2062, DOI 10.17487/RFC2062, December 1996,
<https://www.rfc-editor.org/info/rfc2062>. <https://www.rfc-editor.org/info/rfc2062>.
[IMAP-TLS] Newman, C., "Using TLS with IMAP, POP3 and ACAP",
RFC 2595, DOI 10.17487/RFC2595, June 1999,
<https://www.rfc-editor.org/info/rfc2595>.
[IMAP2] Crispin, M., "Interactive Mail Access Protocol: Version [IMAP2] Crispin, M., "Interactive Mail Access Protocol: Version
2", RFC 1176, August 1990, 2", RFC 1176, DOI 10.17487/RFC1176, August 1990,
<https://www.rfc-editor.org/info/rfc1176>. <https://www.rfc-editor.org/info/rfc1176>.
[RFC-822] Crocker, D., "STANDARD FOR THE FORMAT OF ARPA INTERNET [IMAP2BIS] Crispin, M., "INTERACTIVE MAIL ACCESS PROTOCOL - VERSION
TEXT MESSAGES", STD 11, RFC 822, August 1982, 2bis", Work in Progress, Internet-Draft, draft-ietf-imap-
<https://www.rfc-editor.org/info/rfc822>. imap2bis-02, 29 October 1993,
<https://datatracker.ietf.org/doc/html/draft-ietf-imap-
imap2bis-02>.
[IMAP-TLS] [RFC1064] Crispin, M., "Interactive Mail Access Protocol: Version
Newman, C., "Using TLS with IMAP, POP3 and ACAP", 2", RFC 1064, DOI 10.17487/RFC1064, July 1988,
RFC 2595, June 1999, <https://www.rfc-editor.org/info/rfc1064>.
<https://www.rfc-editor.org/info/rfc2595>.
Appendix A. Backward compatibility with IMAP4rev1 [RFC1730] Crispin, M., "Internet Message Access Protocol - Version
4", RFC 1730, DOI 10.17487/RFC1730, December 1994,
<https://www.rfc-editor.org/info/rfc1730>.
[RFC2060] Crispin, M., "Internet Message Access Protocol - Version
4rev1", RFC 2060, DOI 10.17487/RFC2060, December 1996,
<https://www.rfc-editor.org/info/rfc2060>.
[RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION
4rev1", RFC 3501, DOI 10.17487/RFC3501, March 2003,
<https://www.rfc-editor.org/info/rfc3501>.
[RFC822] Crocker, D., "STANDARD FOR THE FORMAT OF ARPA INTERNET
TEXT MESSAGES", STD 11, RFC 822, DOI 10.17487/RFC0822,
August 1982, <https://www.rfc-editor.org/info/rfc822>.
Appendix A. Backward Compatibility with IMAP4rev1
An implementation that wants to remain compatible with IMAP4rev1 can An implementation that wants to remain compatible with IMAP4rev1 can
advertise both IMAP4rev1 and IMAP4rev2 in its CAPABILITY response/ advertise both IMAP4rev1 and IMAP4rev2 in its CAPABILITY response /
response code. (Such server implementation is likely to also want to response code. (Such server implementation is likely to also want to
advertise other IMAP4rev1 extensions that were folded into IMAP4rev2. advertise other IMAP4rev1 extensions that were folded into IMAP4rev2;
See Appendix E.) While some IMAP4rev1 responses were removed in see Appendix E.) While some IMAP4rev1 responses were removed in
IMAP4rev2, their presence will not break IMAP4rev2-only clients. IMAP4rev2, their presence will not break IMAP4rev2-only clients.
If both IMAP4rev1 and IMAP4rev2 are advertised, an IMAP client that If both IMAP4rev1 and IMAP4rev2 are advertised, an IMAP client that
wants to use IMAP4rev2 MUST issue an "ENABLE IMAP4rev2" command. wants to use IMAP4rev2 MUST issue an "ENABLE IMAP4rev2" command.
When compared to IMAP4rev1, some request data items, corresponding
response data items, and responses were removed in IMAP4rev2. See
Appendix E for more details. With the exception of obsolete SEARCH
and RECENT responses, servers advertising both IMAP4rev1 and
IMAP4rev2 would never return such removed response data items/
responses unless explicitly requested by an IMAPrev1 client.
Servers advertising both IMAP4rev1 and IMAP4rev2 MUST NOT generate Servers advertising both IMAP4rev1 and IMAP4rev2 MUST NOT generate
UTF-8 quoted strings unless the client has issued "ENABLE IMAP4rev2". UTF-8-quoted strings unless the client has issued "ENABLE IMAP4rev2".
Consider implementation of mechanisms described or referenced in Consider implementation of mechanisms described or referenced in
[IMAP-UTF-8] to achieve this goal. [IMAP-UTF-8] to achieve this goal.
Servers advertising both IMAP4rev1 and IMAP4rev2, and clients Servers advertising both IMAP4rev1 and IMAP4rev2, and clients
intending to be compatible with IMAP4rev1 servers MUST be compatible intending to be compatible with IMAP4rev1 servers, MUST be compatible
with the international mailbox naming convention described in with the Mailbox International Naming Convention described in
Appendix A.1. Appendix A.1.
Also see Appendix D for special considerations for servers that Also see Appendix D for special considerations for servers that
support 63 bit body part/message sizes and want to advertise support support 63-bit body part / message sizes and want to advertise
for both IMAP4rev1 and IMAP4rev2. support for both IMAP4rev1 and IMAP4rev2.
A.1. Mailbox International Naming Convention for compatibility with A.1. Mailbox International Naming Convention for Compatibility with
IMAP4rev1 IMAP4rev1
Support for the Mailbox International Naming Convention described in Support for the Mailbox International Naming Convention described in
this section is not required for IMAP4rev2-only clients and servers. this section is not required for IMAP4rev2-only clients and servers.
It is only used for backward compatibility with IMAP4rev1 It is only used for backward compatibility with IMAP4rev1
implementations. implementations.
By convention, international mailbox names in IMAP4rev1 are specified By convention, international mailbox names in IMAP4rev1 are specified
using a modified version of the UTF-7 encoding described in [UTF-7]. using a modified version of the UTF-7 encoding described in [UTF-7].
Modified UTF-7 may also be usable in servers that implement an Modified UTF-7 may also be usable in servers that implement an
earlier version of this protocol. earlier version of this protocol.
In modified UTF-7, printable US-ASCII characters, except for "&", In modified UTF-7, printable US-ASCII characters, except for "&",
represent themselves; that is, characters with octet values 0x20-0x25 represent themselves; that is, characters with octet values 0x20-0x25
and 0x27-0x7e. The character "&" (0x26) is represented by the two- and 0x27-0x7e. The character "&" (0x26) is represented by the
octet sequence "&-". 2-octet sequence "&-".
All other characters (octet values 0x00-0x1f and 0x7f-0xff) are All other characters (octet values 0x00-0x1f and 0x7f-0xff) are
represented in modified BASE64, with a further modification from represented in modified base64, with a further modification from
[UTF-7] that "," is used instead of "/". Modified BASE64 MUST NOT be [UTF-7] that "," is used instead of "/". Modified base64 MUST NOT be
used to represent any printing US-ASCII character which can represent used to represent any printing of a US-ASCII character that can
itself. Only characters inside the modified BASE64 alphabet are represent itself. Only characters inside the modified base64
permitted in modified BASE64 text. alphabet are permitted in modified base64 text.
"&" is used to shift to modified BASE64 and "-" to shift back to US- "&" is used to shift to modified base64 and "-" to shift back to US-
ASCII. There is no implicit shift from BASE64 to US-ASCII, and null ASCII. There is no implicit shift from base64 to US-ASCII, and null
shifts ("-&" while in BASE64; note that "&-" while in US-ASCII means shifts ("-&" while in base64; note that "&-" while in US-ASCII means
"&") are not permitted. However, all names start in US-ASCII, and "&") are not permitted. However, all names start in US-ASCII and
MUST end in US-ASCII; that is, a name that ends with a non-ASCII MUST end in US-ASCII; that is, a name that ends with a non-ASCII
ISO-10646 character MUST end with a "-"). ISO-10646 character MUST end with a "-".
The purpose of these modifications is to correct the following The purpose of these modifications is to correct the following
problems with UTF-7: problems with UTF-7:
1. UTF-7 uses the "+" character for shifting; this conflicts with 1. UTF-7 uses the "+" character for shifting; this conflicts with
the common use of "+" in mailbox names, in particular USENET the common use of "+" in mailbox names, in particular USENET
newsgroup names. newsgroup names.
2. UTF-7's encoding is BASE64 which uses the "/" character; this 2. UTF-7's encoding is base64, which uses the "/" character; this
conflicts with the use of "/" as a popular hierarchy delimiter. conflicts with the use of "/" as a popular hierarchy delimiter.
3. UTF-7 prohibits the unencoded usage of "\"; this conflicts with 3. UTF-7 prohibits the unencoded usage of "\"; this conflicts with
the use of "\" as a popular hierarchy delimiter. the use of "\" as a popular hierarchy delimiter.
4. UTF-7 prohibits the unencoded usage of "~"; this conflicts with 4. UTF-7 prohibits the unencoded usage of "~"; this conflicts with
the use of "~" in some servers as a home directory indicator. the use of "~" in some servers as a home directory indicator.
5. UTF-7 permits multiple alternate forms to represent the same 5. UTF-7 permits multiple alternate forms to represent the same
string; in particular, printable US-ASCII characters can be string; in particular, printable US-ASCII characters can be
represented in encoded form. represented in encoded form.
Although modified UTF-7 is a convention, it establishes certain Although modified UTF-7 is a convention, it establishes certain
requirements on server handling of any mailbox name with an embedded requirements on the server handling of any mailbox name with an
"&" character. In particular, server implementations MUST preserve embedded "&" character. In particular, server implementations MUST
the exact form of the modified BASE64 portion of a modified UTF-7 preserve the exact form of the modified base64 portion of a modified
name and treat that text as case-sensitive, even if names are UTF-7 name and treat that text as case sensitive, even if names are
otherwise case-insensitive or case-folded. otherwise case insensitive or case folded.
Server implementations SHOULD verify that any mailbox name with an Server implementations SHOULD verify that any mailbox name with an
embedded "&" character, used as an argument to CREATE, is: in the embedded "&" character, used as an argument to CREATE, is: in the
correctly modified UTF-7 syntax, has no superfluous shifts, and has correctly modified UTF-7 syntax; has no superfluous shifts; and has
no encoding in modified BASE64 of any printing US-ASCII character no encoding in modified base64 of any printing US-ASCII character
which can represent itself. However, client implementations MUST NOT that can represent itself. However, client implementations MUST NOT
depend upon the server doing this, and SHOULD NOT attempt to create a depend upon the server doing this and SHOULD NOT attempt to create a
mailbox name with an embedded "&" character unless it complies with mailbox name with an embedded "&" character unless it complies with
the modified UTF-7 syntax. the modified UTF-7 syntax.
Server implementations which export a mail store that does not follow Server implementations that export a mail store that does not follow
the modified UTF-7 convention MUST convert to modified UTF-7 any the modified UTF-7 convention MUST convert any mailbox name that
mailbox name that contains either non-ASCII characters or the "&" contains either non-ASCII characters or the "&" character to modified
character. UTF-7.
For example, here is a mailbox name which mixes English, Chinese, For example, here is a mailbox name that mixes English, Chinese,
and Japanese text: ~peter/mail/&U,BTFw-/&ZeVnLIqe- and Japanese text: ~peter/mail/&U,BTFw-/&ZeVnLIqe-
For example, the string "&Jjo!" is not a valid mailbox name For example, the string "&Jjo!" is not a valid mailbox name
because it does not contain a shift to US-ASCII before the "!". because it does not contain a shift to US-ASCII before the "!".
The correct form is "&Jjo-!". The string "&U,BTFw-&ZeVnLIqe-" is The correct form is "&Jjo-!". The string "&U,BTFw-&ZeVnLIqe-" is
not permitted because it contains a superfluous shift. The not permitted because it contains a superfluous shift. The
correct form is "&U,BTF2XlZyyKng-". correct form is "&U,BTF2XlZyyKng-".
Appendix B. Backward compatibility with BINARY extension Appendix B. Backward Compatibility with BINARY Extension
IMAP4rev2 incorporates subset of functionality provided by the BINARY IMAP4rev2 incorporates a subset of functionality provided by the
extension [RFC3516], in particular it includes additional FETCH items BINARY extension [RFC3516]; in particular, it includes additional
(BINARY, BINARY.PEEK and BINARY.SIZE), but not extensions to the FETCH items (BINARY, BINARY.PEEK, and BINARY.SIZE) but not extensions
APPEND command. IMAP4rev2 implementations that supports full RFC to the APPEND command. IMAP4rev2 implementations that support full
3516 functionality need to also advertise the BINARY capability in [RFC3516] functionality need to also advertise the BINARY capability
the CAPABILITY response/response code. in the CAPABILITY response / response code.
Appendix C. Backward compatibility with LIST-EXTENDED extension Appendix C. Backward Compatibility with LIST-EXTENDED Extension
IMAP4rev2 incorporates most of functionality provided by the LIST- IMAP4rev2 incorporates most of the functionality provided by the
EXTENDED extension [RFC5258]. In particular, multiple mailbox LIST-EXTENDED extension [RFC5258]. In particular, the syntax for
patterns syntax is not supported in IMAP4rev2, unless LIST-EXTENDED multiple mailbox patterns is not supported in IMAP4rev2, unless LIST-
capability is also advertised in the CAPABILITY response/response EXTENDED capability is also advertised in the CAPABILITY response /
code. response code.
Appendix D. 63 bit body part and message sizes Appendix D. 63-Bit Body Part and Message Sizes
IMAP4rev2 increases allowed body part and message sizes that servers IMAP4rev2 increases allowed body part and message sizes that servers
can support from 32 to 63 bits. Server implementations don't have to can support from 32 to 63 bits. Server implementations don't have to
support 63 bit long body parts/message sizes, however client support 63-bit-long body parts/message sizes; however, client
implementations have to expect them. implementations have to expect them.
As IMAP4rev1 didn't support 63 bit long body part/message sizes, As IMAP4rev1 didn't support 63-bit-long body part / message sizes,
there is an interoperability issue exposed by 63 bit capable servers there is an interoperability issue exposed by 63-bit-capable servers/
that are accessible by both IMAP4rev1 and IMAP4rev2 email clients. mailboxes that are accessible by both IMAP4rev1 and IMAP4rev2 email
As IMAP4rev1 would be unable to retrieve full content of messages clients. As IMAP4rev1 would be unable to retrieve the full content
bigger than 4Gb, such servers either need to replace messages bigger of messages bigger than 4 Gb, such servers either need to replace
that 4Gb with messages under 4Gb or hide them from IMAP4rev1 clients. messages bigger that 4 Gb with messages under 4 Gb or hide them from
This document doesn't prescribe any implementation strategy to IMAP4rev1 clients. This document doesn't prescribe any
address this issue. implementation strategy to address this issue.
Appendix E. Changes from RFC 3501 / IMAP4rev1 Appendix E. Changes from RFC 3501 / IMAP4rev1
Below is the summary of changes since RFC 3501: Below is the summary of changes since RFC 3501:
1. Support for 64bit message and body part sizes. 1. Support for 64-bit message and body part sizes.
2. Folded in IMAP NAMESPACE (RFC 2342), UNSELECT (RFC 3691), 2. Folded in IMAP NAMESPACE [RFC2342], UNSELECT [RFC3691], UIDPLUS
UIDPLUS (RFC 4315), ESEARCH (RFC 4731), SEARCHRES (RFC 5182), [RFC4315], ESEARCH [RFC4731], SEARCHRES [RFC5182], ENABLE
ENABLE (RFC 5161), IDLE (RFC 2177), SASL-IR (RFC 4959), LIST- [RFC5161], IDLE [RFC2177], SASL-IR [RFC4959], LIST-EXTENDED
EXTENDED (RFC 5258), LIST-STATUS (RFC 5819), MOVE (RFC 6851) and [RFC5258], LIST-STATUS [RFC5819], MOVE [RFC6851], and LITERAL-
LITERAL- (RFC 7888) extensions. Also folded RFC 4466 (IMAP ABNF extensions [RFC7888]. Also folded in IMAP ABNF extensions
extensions), RFC 5530 (response codes), the FETCH side of the [RFC4466], response codes [RFC5530], the FETCH side of the
BINARY extension (RFC 3516) and the list of new mailbox BINARY extension [RFC3516], and the list of new mailbox
attributes from SPECIAL-USE (RFC 6154). attributes from SPECIAL-USE [RFC6154].
3. Added STATUS SIZE (RFC 8438) and STATUS DELETED. 3. Added STATUS SIZE [RFC8438] and STATUS DELETED.
4. SEARCH command now requires to return ESEARCH response (SEARCH 4. SEARCH command now requires to return the ESEARCH response
response is now deprecated). (SEARCH response is now deprecated).
5. Clarified which SEARCH keys have to use substring match and 5. Clarified which SEARCH keys have to use substring match and
which don't. which don't.
6. Clarified that server should decode parameter value 6. Clarified that the server should decode parameter value
continuations as described in [RFC2231]. This requirement was continuations as described in [RFC2231]. This requirement was
hidden in RFC 2231 itself. hidden in [RFC2231] itself.
7. Clarified that COPYUID response code is returned for both MOVE 7. Clarified that the COPYUID response code is returned for both
and UID MOVE. MOVE and UID MOVE.
8. Tighen requirements about COPY/MOVE commands not creating target 8. Tightened requirements about COPY/MOVE commands not creating a
mailbox. Also require them to return TRYCREATE response code, target mailbox. Also required them to return the TRYCREATE
if the target mailbox doesn't exist and can be created. response code, if the target mailbox doesn't exist and can be
created.
9. Added CLOSED response code from RFC 7162. SELECT/EXAMINE when a 9. Added the CLOSED response code from [RFC7162]. SELECT/EXAMINE
mailbox is already selected now requires a CLOSED response code when a mailbox is already selected now requires a CLOSED
to be returned. response code to be returned.
10. SELECT/EXAMINE are now required to return untagged LIST 10. SELECT/EXAMINE are now required to return an untagged LIST
response. response.
11. UNSEEN response code on SELECT/EXAMINE is now deprecated. 11. UNSEEN response code on SELECT/EXAMINE is now deprecated.
12. RECENT response on SELECT/EXAMINE, \Recent flag, RECENT STATUS, 12. RECENT response on SELECT/EXAMINE, \Recent flag, RECENT STATUS,
SEARCH NEW items are now deprecated. and SEARCH NEW items are now deprecated.
13. Clarified that the server doesn't need to send a new 13. Clarified that the server doesn't need to send a new
PERMANENTFLAGS response code when a new keyword was successfully PERMANENTFLAGS response code when a new keyword was successfully
added and the server advertised \* earlier for the same mailbox. added and the server advertised \* earlier for the same mailbox.
14. For future extensibility extended ABNF for tagged-ext-simple to 14. For future extensibility, extended ABNF for tagged-ext-simple to
allow for bare number64. allow for bare number64.
15. Added SHOULD level requirement on IMAP servers to support 15. Added SHOULD level requirement on IMAP servers to support
$MDNSent, $Forwarded, $Junk, $NonJunk and $Phishing keywords. $MDNSent, $Forwarded, $Junk, $NonJunk, and $Phishing keywords.
16. Mailbox names and message headers now allow for UTF-8. Support 16. Mailbox names and message headers now allow for UTF-8. Support
for Modified UTF-7 in mailbox names is not required, unless for modified UTF-7 in mailbox names is not required, unless
compatibility with IMAP4rev1 is desired. compatibility with IMAP4rev1 is desired.
17. Removed the CHECK command. Clients should use NOOP instead. 17. Removed the CHECK command. Clients should use NOOP instead.
18. RFC822, RFC822.HEADER and RFC822.TEXT FETCH data items were 18. RFC822, RFC822.HEADER, and RFC822.TEXT FETCH data items were
deprecated. Clients should use the corresponding BODY[] deprecated. Clients should use the corresponding BODY[]
variants instead. variants instead.
19. LSUB command was deprecated. Clients should use LIST 19. LSUB command was deprecated. Clients should use LIST
(SUBSCRIBED) instead. (SUBSCRIBED) instead.
20. IDLE command can now return updates not related to the currently 20. IDLE command can now return updates not related to the currently
selected mailbox state. selected mailbox state.
21. All unsolicited FETCH updates are required to include UID. 21. All unsolicited FETCH updates are required to include UID.
22. Clarified that client implementations MUST ignore response codes 22. Clarified that client implementations MUST ignore response codes
that they do not recognize. (Change from a SHOULD to a MUST.) that they do not recognize. (Changed from a SHOULD to a MUST.)
23. resp-text ABNF non terminal was updated to allow for empty text. 23. resp-text ABNF non-terminal was updated to allow for empty text.
24. After ENABLE IMAP4rev2 human readable response text can include 24. After ENABLE, IMAP4rev2 human-readable response text can include
non ASCII encoded in UTF-8. non-ASCII encoded in UTF-8.
25. Updated to use modern TLS-related recommendations as per RFC 25. Updated to use modern TLS-related recommendations as per
8314, RFC 7817, RFC 7525. [RFC7525], [RFC7817], and [RFC8314].
26. Added warnings about use of ALERT response codes and PREAUTH 26. Added warnings about use of ALERT response codes and PREAUTH
response. response.
27. Replaced DIGEST-MD5 SASL mechanism with SCRAM-SHA-256. DIGEST- 27. Replaced DIGEST-MD5 SASL mechanism with SCRAM-SHA-256. DIGEST-
MD5 was deprecated. MD5 was deprecated.
28. Clarified that any command received from the client resets 28. Clarified that any command received from the client resets
server autologout timer. server autologout timer.
29. Revised IANA registration procedure for IMAP extensions and 29. Revised IANA registration procedure for IMAP extensions and
removed "X" convention in accordance with BCP 178. removed "X" convention in accordance with [BCP178].
30. Loosened requirements on servers when closing connections to be 30. Loosened requirements on servers when closing connections to be
more aligned with existing practices. more aligned with existing practices.
Appendix F. Other Recommended IMAP Extensions Appendix F. Other Recommended IMAP Extensions
Support for the following extensions is recommended for all IMAP Support for the following extensions is recommended for all IMAP
client and servers. While they significantly reduce bandwidth and/or clients and servers. While they significantly reduce bandwidth and/
number of round trips used by IMAP in certain situations, the EXTRA or number of round trips used by IMAP in certain situations, the
WG decided that requiring them as a part of IMAP4rev2 would push the EXTRA WG decided that requiring them as a part of IMAP4rev2 would
bar to implement too high for new implementations. Also note that push the bar to implement too high for new implementations. Also
absence of any IMAP extension from this list doesn't make it somehow note that the absence of any IMAP extension from this list doesn't
deficient or not recommended for use with IMAP4rev2. make it somehow deficient or not recommended for use with IMAP4rev2.
1. QRESYNC and CONDSTORE extensions [RFC7162]. They make 1. Quick Mailbox Resynchronization (QRESYNC) and CONDSTORE
discovering changes to IMAP mailboxes more efficient, at the extensions [RFC7162]. They make discovering changes to IMAP
expense of storing a bit more state. mailboxes more efficient, at the expense of storing a bit more
state.
2. OBJECTID extension [RFC8474] helps with preserving IMAP client 2. OBJECTID extension [RFC8474] helps with preserving the IMAP
cache when messages moved/copied or mailboxes are renamed. client cache when messages are moved/copied or mailboxes are
renamed.
Appendix G. Acknowledgement Acknowledgements
Earlier versions of this document were edited by Mark Crispin. Earlier draft versions of this document were edited by Mark Crispin.
Sadly, he is no longer available to help with this work. Editors of Sadly, he is no longer available to help with this work. Editors of
this revisions are hoping that Mark would have approved. this revision are hoping that Mark would have approved.
Chris Newman has contributed text on I18N and use of UTF-8 in Chris Newman has contributed text on I18N and use of UTF-8 in
messages and mailbox names. messages and mailbox names.
Thank you to Tony Hansen for helping with the index generation. Thank you to Tony Hansen for helping with the index generation.
Thank you to Murray Kucherawy, Timo Sirainen, Bron Gondwana, Stephan Thank you to Murray Kucherawy, Timo Sirainen, Bron Gondwana, Stephan
Bosch, Robert Sparks, Arnt Gulbrandsen, Benjamin Kaduk, Daniel Bosch, Robert Sparks, Arnt Gulbrandsen, Benjamin Kaduk, Daniel
Migault, Roman Danyliw and Eric Vyncke for extensive feedback. Migaul, Roman Danyliw, and Éric Vyncke for extensive feedback.
This document incorporates text from RFC 4315 (by Mark Crispin), RFC This document incorporates text from [RFC2342] (by Mike Gahrns and
4466 (by Cyrus Daboo), RFC 4731 (by Dave Cridland), RFC 5161 (by Arnt Chris Newman), [RFC3516] (by Lyndon Nerenberg), [RFC4315] (by Mark
Gulbrandsen), RFC 5465 (by Arnt Gulbrandsen and Curtis King), RFC Crispin), [RFC4466] (by Cyrus Daboo), [RFC4731] (by Dave Cridland),
5530 (by Arnt Gulbrandsen), RFC 5819 (by Timo Sirainen), RFC 6154 (by [RFC4959] (by Rob Siemborski and Arnt Gulbrandsen), [RFC5161] (by
Jamie Nicolson), RFC 8438 (by Stephan Bosch) so work done by authors/ Arnt Gulbrandsen), [RFC5465] (by Arnt Gulbrandsen and Curtis King),
[RFC5530] (by Arnt Gulbrandsen), [RFC5819] (by Timo Sirainen),
[RFC6154] (by Jamie Nicolson), [RFC6851] (by Arnt Gulbrandsen and Ned
Freed), and [RFC8438] (by Stephan Bosch), so work done by authors/
editors of these documents is appreciated. Note that editors of this editors of these documents is appreciated. Note that editors of this
document were redacted from the above list. document were redacted from the above list.
The CHILDREN return option was originally proposed by Mike Gahrns and The CHILDREN return option was originally proposed by Mike Gahrns and
Raymond Cheng in [RFC3348]. Most of the information in Raymond Cheng in [RFC3348]. Most of the information in
Section 6.3.9.5 is taken directly from their original specification Section 6.3.9.5 is taken directly from their original specification
[RFC3348]. [RFC3348].
Thank you to Damian Poddebniak, Fabian Ising, Hanno Boeck and Thank you to Damian Poddebniak, Fabian Ising, Hanno Boeck, and
Sebastian Schinzel for pointing out that the ENABLE command should be Sebastian Schinzel for pointing out that the ENABLE command should be
a member of "command-auth" and not "command-any" ABNF production, as a member of "command-auth" and not "command-any" ABNF production, as
well as pointing out security issues associated with ALERT, PREAUTH well as pointing out security issues associated with ALERT, PREAUTH,
and other responses received before authentication. and other responses received before authentication.
Index Index
$ $ + - \ A B C D E F H I K L M N O P R S T U
$Forwarded (predefined flag) 13
$Junk (predefined flag) 13
$MDNSent (predefined flag) 13
$NotJunk (predefined flag) 13
$Phishing (predefined flag) 13
+ $
+FLAGS <flag list> 97
+FLAGS.SILENT <flag list> 97
- $Forwarded (predefined flag)
-FLAGS <flag list> 97 Section 2.3.2
-FLAGS.SILENT <flag list> 97 $Junk (predefined flag)
Section 2.3.2
$MDNSent (predefined flag)
Section 2.3.2
$NotJunk (predefined flag)
Section 2.3.2
$Phishing (predefined flag)
Section 2.3.2, Paragraph 6.10.1
A +
ALERT (response code) 105
ALL (fetch item) 93
ALL (search key) 82
ALL (search result option) 80
ALL (search return item name) 122
ALREADYEXISTS (response code) 105
ANSWERED (search key) 82
APPEND (command) 73
APPENDUID (response code) 105
AUTHENTICATE (command) 31
AUTHENTICATIONFAILED (response code) 106
AUTHORIZATIONFAILED (response code) 106
B +FLAGS <flag list>
BAD (response) 113 Section 6.4.6
BADCHARSET (response code) 106 +FLAGS.SILENT <flag list>
BCC <string> (search key) 82 Section 6.4.6
BEFORE <date> (search key) 82
BINARY.PEEK[<section-binary>]<<partial>> (fetch item) 93
BINARY.SIZE[<section-binary>] (fetch item) 94
BINARY.SIZE[<section-binary>] (fetch result) 125
BINARY[<section-binary>]<<number>> (fetch result) 124
BINARY[<section-binary>]<<partial>> (fetch item) 93
BODY (fetch item) 94
BODY (fetch result) 125
BODY <string> (search key) 82
BODY.PEEK[<section>]<<partial>> (fetch item) 94
BODYSTRUCTURE (fetch item) 95
BODYSTRUCTURE (fetch result) 126
BODY[<section>]<<origin octet>> (fetch result) 125
BODY[<section>]<<partial>> (fetch item) 94
BYE (response) 114
Body Structure (message attribute) 14
C -
CANNOT (response code) 106
CAPABILITY (command) 27
CAPABILITY (response code) 107
CAPABILITY (response) 115
CC <string> (search key) 82
CLIENTBUG (response code) 107
CLOSE (command) 78
CLOSED (response code) 107
CONTACTADMIN (response code) 107
COPY (command) 98
COPYUID (response code) 108
CORRUPTION (response code) 108
COUNT (search result option) 81
COUNT (search return item name) 122
CREATE (command) 41
D -FLAGS <flag list>
DELETE (command) 42 Section 6.4.6
DELETED (search key) 83 -FLAGS.SILENT <flag list>
DELETED (status item) 73 Section 6.4.6
DRAFT (search key) 83
E \
ENABLE (command) 36
ENVELOPE (fetch item) 95
ENVELOPE (fetch result) 129
ESEARCH (response) 121
EXAMINE (command) 40
EXPIRED (response code) 108
EXPUNGE (command) 79
EXPUNGE (response) 123
EXPUNGEISSUED (response code) 108
Envelope Structure (message attribute) 14
F \All (mailbox name attribute)
FAST (fetch item) 93 Section 7.3.1
FETCH (command) 92 \Answered (system flag)
FETCH (response) 124 Section 2.3.2
FLAGGED (search key) 83 \Archive (mailbox name attribute)
FLAGS (fetch item) 95 Section 7.3.1
FLAGS (fetch result) 130 \Deleted (system flag)
FLAGS (response) 123 Section 2.3.2
FLAGS <flag list> (store command data item) 97 \Draft (system flag)
FLAGS.SILENT <flag list> (store command data item) 97 Section 2.3.2
FROM <string> (search key) 83 \Drafts (mailbox name attribute)
FULL (fetch item) 93 Section 7.3.1
Flags (message attribute) 12 \Flagged (mailbox name attribute)
Section 7.3.1
\Flagged (system flag)
Section 2.3.2
\HasChildren (mailbox name attribute)
Section 7.3.1
\HasNoChildren (mailbox name attribute)
Section 7.3.1
\Junk (mailbox name attribute)
Section 7.3.1
\Marked (mailbox name attribute)
Section 7.3.1
\Noinferiors (mailbox name attribute)
Section 7.3.1
\NonExistent (mailbox name attribute)
Section 7.3.1, Paragraph 4.2.1
\Noselect (mailbox name attribute)
Section 7.3.1
\Recent (system flag)
Section 2.3.2
\Remote (mailbox name attribute)
Section 7.3.1
\Seen (system flag)
Section 2.3.2
\Sent (mailbox name attribute)
Section 7.3.1
\Subscribed (mailbox name attribute)
Section 7.3.1
\Trash (mailbox name attribute)
Section 7.3.1
\Unmarked (mailbox name attribute)
Section 7.3.1
H A
HASCHILDREN (response code) 109
HEADER (part specifier) 95
HEADER <field-name> <string> (search key) 83
HEADER.FIELDS (part specifier) 95
HEADER.FIELDS.NOT (part specifier) 95
I ALERT (response code)
IDLE (command) 76 Section 7.1
INTERNALDATE (fetch item) 95 ALL (fetch item)
INTERNALDATE (fetch result) 130 Section 6.4.5
INUSE (response code) 109 ALL (search key)
Internal Date (message attribute) 14 Section 6.4.4
ALL (search result option)
Section 6.4.4, Paragraph 6.6.1
ALL (search return item name)
Section 7.3.4, Paragraph 7.6.1
ALREADYEXISTS (response code)
Section 7.1, Paragraph 4.4.1
ANSWERED (search key)
Section 6.4.4
APPEND (command)
Section 6.3.12
APPENDUID (response code)
Section 7.1, Paragraph 4.6.1
AUTHENTICATE (command)
Section 6.2.2
AUTHENTICATIONFAILED (response code)
Section 7.1, Paragraph 4.8.1
AUTHORIZATIONFAILED (response code)
Section 7.1, Paragraph 4.10.1
K B
KEYWORD <flag> (search key) 83
Keyword (type of flag) 12
L BAD (response)
LARGER <n> (search key) 83 Section 7.1.3
LIMIT (response code) 109 BADCHARSET (response code)
LIST (command) 48 Section 7.1
LIST (response) 117 BCC <string> (search key)
LOGOUT (command) 28 Section 6.4.4
BEFORE <date> (search key)
Section 6.4.4
BINARY.PEEK[<section-binary>]<<partial>> (fetch item)
Section 6.4.5
BINARY.SIZE[<section-binary>] (fetch item)
Section 6.4.5, Paragraph 9.6.1
BINARY.SIZE[<section-binary>] (fetch result)
Section 7.5.2, Paragraph 4.4.1
BINARY[<section-binary>]<<number>> (fetch result)
Section 7.5.2, Paragraph 4.2.1
BINARY[<section-binary>]<<partial>> (fetch item)
Section 6.4.5, Paragraph 9.2.1
BODY (fetch item)
Section 6.4.5
BODY (fetch result)
Section 7.5.2
BODY <string> (search key)
Section 6.4.4
BODY.PEEK[<section>]<<partial>> (fetch item)
Section 6.4.5
BODYSTRUCTURE (fetch item)
Section 6.4.5
BODYSTRUCTURE (fetch result)
Section 7.5.2, Paragraph 4.10.1
BODY[<section>]<<origin octet>> (fetch result)
Section 7.5.2, Paragraph 4.8.1
BODY[<section>]<<partial>> (fetch item)
Section 6.4.5, Paragraph 9.10.1
BYE (response)
Section 7.1.5
Body Structure (message attribute)
Section 2.3.6
M C
MAX (search result option) 80
MAX (search return item name) 122
MAY (specification requirement term) 5
MESSAGES (status item) 72
MIME (part specifier) 96
MIN (search result option) 80
MIN (search return item name) 122
MOVE (command) 99
MUST (specification requirement term) 5
MUST NOT (specification requirement term) 5
Message Sequence Number (message attribute) 11
N CANNOT (response code)
NAMESPACE (command) 66 Section 7.1, Paragraph 4.14.1
NAMESPACE (response) 121 CAPABILITY (command)
NO (response) 113 Section 6.1.1
NONEXISTENT (response code) 109 CAPABILITY (response code)
NOOP (command) 28 Section 7.1
NOPERM (response code) 110 CAPABILITY (response)
NOT <search-key> (search key) 83 Section 7.2.2
NOT RECOMMENDED (specification requirement term) 5 CC <string> (search key)
Section 6.4.4
CLIENTBUG (response code)
Section 7.1, Paragraph 4.18.1
CLOSE (command)
Section 6.4.1
CLOSED (response code)
Section 7.1, Paragraph 4.20.1
CONTACTADMIN (response code)
Section 7.1, Paragraph 4.22.1
COPY (command)
Section 6.4.7
COPYUID (response code)
Section 7.1, Paragraph 4.24.1
CORRUPTION (response code)
Section 7.1, Paragraph 4.26.1
COUNT (search result option)
Section 6.4.4
COUNT (search return item name)
Section 7.3.4
CREATE (command)
Section 6.3.4
O D
OK (response) 113
ON <date> (search key) 83
OPTIONAL (specification requirement term) 5
OR <search-key1> <search-key2> (search key) 83
OVERQUOTA (response code) 110
P DELETE (command)
PARSE (response code) 110 Section 6.3.5
PERMANENTFLAGS (response code) 110 DELETED (search key)
PREAUTH (response) 114 Section 6.4.4
PRIVACYREQUIRED (response code) 111 DELETED (status item)
Permanent Flag (class of flag) 14 Section 6.3.11
Predefined keywords 13 DRAFT (search key)
Section 6.4.4
R E
READ-ONLY (response code) 111
READ-WRITE (response code) 111
RECOMMENDED (specification requirement term) 5
RENAME (command) 44
REQUIRED (specification requirement term) 5
RFC822.SIZE (fetch item) 95
RFC822.SIZE (fetch result) 130
S ENABLE (command)
SAVE (search result option) 81 Section 6.3.1
SEARCH (command) 79 ENVELOPE (fetch item)
SEEN (search key) 83 Section 6.4.5
SELECT (command) 38 ENVELOPE (fetch result)
SENTBEFORE <date> (search key) 83 Section 7.5.2, Paragraph 4.42.1
SENTON <date> (search key) 83 ESEARCH (response)
SENTSINCE <date> (search key) 83 Section 7.3.4
SERVERBUG (response code) 111 EXAMINE (command)
SHOULD (specification requirement term) 5 Section 6.3.3
SHOULD NOT (specification requirement term) 5 EXPIRED (response code)
SINCE <date> (search key) 84 Section 7.1, Paragraph 4.28.1
SIZE (status item) 73 EXPUNGE (command)
SMALLER <n> (search key) 84 Section 6.4.3
STARTTLS (command) 29 EXPUNGE (response)
STATUS (command) 71 Section 7.5.1
STATUS (response) 121 EXPUNGEISSUED (response code)
STORE (command) 97 Section 7.1, Paragraph 4.30.1
SUBJECT <string> (search key) 84 Envelope Structure (message attribute)
SUBSCRIBE (command) 47 Section 2.3.5
Session Flag (class of flag) 14
System Flag (type of flag) 12
T F
TEXT (part specifier) 95
TEXT <string> (search key) 84
TO <string> (search key) 84
TRYCREATE (response code) 111
U FAST (fetch item)
UID (command) 101 Section 6.4.5
UID (fetch item) 95 FETCH (command)
UID (fetch result) 130 Section 6.4.5
UID <sequence set> (search key) 84 FETCH (response)
UIDNEXT (response code) 111 Section 7.5.2
UIDNEXT (status item) 72 FLAGGED (search key)
UIDNOTSTICKY (response code) 112 Section 6.4.4
UIDVALIDITY (response code) 112 FLAGS (fetch item)
UIDVALIDITY (status item) 72 Section 6.4.5
UNANSWERED (search key) 84 FLAGS (fetch result)
UNAVAILABLE (response code) 112 Section 7.5.2
UNDELETED (search key) 84 FLAGS (response)
UNDRAFT (search key) 84 Section 7.3.5
UNFLAGGED (search key) 84 FLAGS <flag list> (store command data item)
UNKEYWORD <flag> (search key) 84 Section 6.4.6
UNKNOWN-CTE (response code) 112 FLAGS.SILENT <flag list> (store command data item)
UNSEEN (search key) 84 Section 6.4.6
UNSEEN (status item) 73 FROM <string> (search key)
UNSELECT (command) 78 Section 6.4.4
UNSUBSCRIBE (command) 47 FULL (fetch item)
Unique Identifier (UID) (message attribute) 10 Section 6.4.5
Flags (message attribute)
Section 2.3.2
[ H
[RFC-5322] Size (message attribute) 14
\ HASCHILDREN (response code)
\All (mailbox name attribute) 119 Section 7.1, Paragraph 4.32.1
\Answered (system flag) 12 HEADER (part specifier)
\Archive (mailbox name attribute) 119 Section 6.4.5.1, Paragraph 5
\Deleted (system flag) 12 HEADER <field-name> <string> (search key)
\Draft (system flag) 12 Section 6.4.4
\Drafts (mailbox name attribute) 119 HEADER.FIELDS (part specifier)
\Flagged (mailbox name attribute) 119 Section 6.4.5.1, Paragraph 5
\Flagged (system flag) 12 HEADER.FIELDS.NOT (part specifier)
\HasChildren (mailbox name attribute) 118 Section 6.4.5.1, Paragraph 5
\HasNoChildren (mailbox name attribute) 118
\Junk (mailbox name attribute) 119 I
\Marked (mailbox name attribute) 118
\Noinferiors (mailbox name attribute) 117 IDLE (command)
\NonExistent (mailbox name attribute) 117 Section 6.3.13
\Noselect (mailbox name attribute) 118 INTERNALDATE ( fetch item)
\Recent (system flag) 12 Section 6.4.5
\Remote (mailbox name attribute) 118 INTERNALDATE (fetch result)
\Seen (system flag) 12 Section 7.5.2
\Sent (mailbox name attribute) 119 INUSE (response code)
\Subscribed (mailbox name attribute) 118 Section 7.1, Paragraph 4.34.1
\Trash (mailbox name attribute) 119 Internal Date (message attribute)
\Unmarked (mailbox name attribute) 118 Section 2.3.3
K
KEYWORD <flag> (search key)
Section 6.4.4
Keyword (type of flag)
Section 2.3.2, Paragraph 4
L
LARGER <n> (search key)
Section 6.4.4
LIMIT (response code)
Section 7.1, Paragraph 4.36.1
LIST (command)
Section 6.3.9
LIST (response)
Section 7.3.1
LOGOUT (command)
Section 6.1.3
M
MAX (search result option)
Section 6.4.4, Paragraph 6.4.1
MAX (search return item name)
Section 7.3.4, Paragraph 7.4.1
MAY (specification requirement term)
Section 1.2
MESSAGES (status item)
Section 6.3.11
MIME (part specifier)
Section 6.4.5.1, Paragraph 7
MIN (search result option)
Section 6.4.4, Paragraph 6.2.1
MIN (search return item name)
Section 7.3.4, Paragraph 7.2.1
MOVE (command)
Section 6.4.8
MUST (specification requirement term)
Section 1.2
MUST NOT (specification requirement term)
Section 1.2
Message Sequence Number (message attribute)
Section 2.3.1.2
N
NAMESPACE (command)
Section 6.3.10
NAMESPACE (response)
Section 7.3.2
NO (response)
Section 7.1.2
NONEXISTENT (response code)
Section 7.1, Paragraph 4.38.1
NOOP (command)
Section 6.1.2
NOPERM (response code)
Section 7.1, Paragraph 4.40.1
NOT <search-key> (search key)
Section 6.4.4
NOT RECOMMENDED (specification requirement term)
Section 1.2
O
OK (response)
Section 7.1.1
ON <date> (search key)
Section 6.4.4
OPTIONAL (specification requirement term)
Section 1.2; Section 1.2
OR <search-key1> <search-key2> (search key)
Section 6.4.4
OVERQUOTA (response code)
Section 7.1, Paragraph 4.42.1
P
PARSE (response code)
Section 7.1
PERMANENTFLAGS (response code)
Section 7.1, Paragraph 4.46.1
PREAUTH (response)
Section 7.1.4
PRIVACYREQUIRED (response code)
Section 7.1, Paragraph 4.48.1
Permanent Flag (class of flag)
Section 2.3.2, Paragraph 9
Predefined keywords
Section 2.3.2, Paragraph 5
R
READ-ONLY (response code)
Section 7.1
READ-WRITE (response code)
Section 7.1
RECOMMENDED (specification requirement term)
Section 1.2
RENAME (command)
Section 6.3.6
REQUIRED (specification requirement term)
Section 1.2
RFC822.SIZE (fetch item)
Section 6.4.5
RFC822.SIZE (fetch result)
Section 7.5.2
RFC822.SIZE (message attribute)
Section 2.3.4
S
SAVE (search result option)
Section 6.4.4, Paragraph 6.10.1
SEARCH (command)
Section 6.4.4
SEEN (search key)
Section 6.4.4
SELECT (command)
Section 6.3.2
SENTBEFORE <date> (search key)
Section 6.4.4
SENTON <date> (search key)
Section 6.4.4
SENTSINCE <date> (search key)
Section 6.4.4
SERVERBUG (response code)
Section 7.1, Paragraph 4.54.1
SHOULD (specification requirement term)
Section 1.2
SHOULD NOT (specification requirement term)
Section 1.2
SINCE <date> (search key)
Section 6.4.4
SIZE (status item)
Section 6.3.11
SMALLER <n> (search key)
Section 6.4.4
STARTTLS (command)
Section 6.2.1
STATUS (command)
Section 6.3.11
STATUS (response)
Section 7.3.3
STORE (command)
Section 6.4.6
SUBJECT <string> (search key)
Section 6.4.4
SUBSCRIBE (command)
Section 6.3.7
Session Flag (class of flag)
Section 2.3.2, Paragraph 9
System Flag (type of flag)
Section 2.3.2, Paragraph 2
T
TEXT (part specifier)
Section 6.4.5.1, Paragraph 5
TEXT <string> (search key)
Section 6.4.4
TO <string> (search key)
Section 6.4.4
TRYCREATE (response code)
Section 7.1
U
UID (command)
Section 6.4.9
UID (fetch item)
Section 6.4.5
UID (fetch result)
Section 7.5.2
UID <sequence set> (search key)
Section 6.4.4
UIDNEXT (response code)
Section 7.1
UIDNEXT (status item)
Section 6.3.11
UIDNOTSTICKY (response code)
Section 7.1, Paragraph 4.60.1
UIDVALIDITY (response code)
Section 7.1
UIDVALIDITY (status item)
Section 6.3.11
UNANSWERED (search key)
Section 6.4.4
UNAVAILABLE (response code)
Section 7.1, Paragraph 4.64.1
UNDELETED (search key)
Section 6.4.4
UNDRAFT (search key)
Section 6.4.4
UNFLAGGED (search key)
Section 6.4.4
UNKEYWORD <flag> (search key)
Section 6.4.4
UNKNOWN-CTE (response code)
Section 7.1
UNSEEN (search key)
Section 6.4.4
UNSEEN (status item)
Section 6.3.11
UNSELECT (command)
Section 6.4.2
UNSUBSCRIBE (command)
Section 6.3.8
Unique Identifier (UID) (message attribute)
Section 2.3.1.1
Authors' Addresses Authors' Addresses
Alexey Melnikov (editor) Alexey Melnikov (editor)
Isode Ltd Isode Ltd
14 Castle Mews 14 Castle Mews
Hampton, Middlesex TW12 2NP Hampton, Middlesex
UK TW12 2NP
United Kingdom
Email: Alexey.Melnikov@isode.com Email: Alexey.Melnikov@isode.com
Barry Leiba (editor) Barry Leiba (editor)
Futurewei Technologies Futurewei Technologies
Phone: +1 646 827 0648
Email: barryleiba@computer.org Email: barryleiba@computer.org
URI: http://internetmessagingtechnology.org/ URI: http://internetmessagingtechnology.org/
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