rfc9209v3.txt   rfc9209v4.txt 
Internet Engineering Task Force (IETF) M. Nottingham Internet Engineering Task Force (IETF) M. Nottingham
Request for Comments: 9209 Fastly Request for Comments: 9209 Fastly
Category: Standards Track P. Sikora Category: Standards Track P. Sikora
ISSN: 2070-1721 Google ISSN: 2070-1721 Google
February 2022 March 2022
The Proxy-Status HTTP Response Header Field The Proxy-Status HTTP Response Header Field
Abstract Abstract
This document defines the Proxy-Status HTTP response field to convey This document defines the Proxy-Status HTTP response field to convey
the details of an intermediary's response handling, including the details of an intermediary's response handling, including
generated errors. generated errors.
Status of This Memo Status of This Memo
skipping to change at line 136 skipping to change at line 136
these can likewise be extended per Section 2.4. these can likewise be extended per Section 2.4.
1.1. Notational Conventions 1.1. Notational Conventions
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 "OPTIONAL" in this document are to be interpreted as described in
BCP 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.
This specification uses Structured Fields [STRUCTURED-FIELDS] to This document uses the following terminology from Section 3 of
specify syntax and parsing and uses ABNF [RFC5234] as shorthand for [STRUCTURED-FIELDS] to specify syntax and parsing: List, String,
that syntax. The terms sf-list, sf-item, sf-string, sf-token, sf- Token, Integer, and Byte Sequence.
integer, and key refer to the structured types defined therein.
Note that in this specification, "proxy" is used to indicate both Note that in this specification, "proxy" is used to indicate both
forward and reverse proxies, otherwise known as gateways. "Next hop" forward and reverse proxies, otherwise known as gateways. "Next hop"
indicates the connection in the direction leading to the origin indicates the connection in the direction leading to the origin
server for the request. server for the request.
2. The Proxy-Status HTTP Field 2. The Proxy-Status HTTP Field
The Proxy-Status HTTP response field allows an intermediary to convey The Proxy-Status HTTP response field allows an intermediary to convey
additional information about its handling of a response and its additional information about its handling of a response and its
associated request. The syntax of this header field conforms to associated request. The syntax of this header field conforms to
[STRUCTURED-FIELDS]. [STRUCTURED-FIELDS].
It is a List ([STRUCTURED-FIELDS], Section 3.1): It is a List ([STRUCTURED-FIELDS], Section 3.1). Each member of the
List represents an intermediary that has handled the response. The
Proxy-Status = sf-list first member represents the intermediary closest to the origin
server, and the last member represents the intermediary closest to
Each member of the List represents an intermediary that has handled the user agent.
the response. The first member of the List represents the
intermediary closest to the origin server, and the last member of the
List represents the intermediary closest to the user agent.
For example: For example:
Proxy-Status: revproxy1.example.net, ExampleCDN Proxy-Status: revproxy1.example.net, ExampleCDN
indicates that this response was handled first by indicates that this response was handled first by
revproxy1.example.net (a reverse proxy adjacent to the origin server) revproxy1.example.net (a reverse proxy adjacent to the origin server)
and then ExampleCDN. and then ExampleCDN.
Intermediaries determine when it is appropriate to add the Proxy- Intermediaries determine when it is appropriate to add the Proxy-
Status field to a response. Some might decide to append it to all Status field to a response. Some might decide to append it to all
responses, whereas others might only do so when specifically responses, whereas others might only do so when specifically
configured to or when the request contains a header field that configured to or when the request contains a header field that
activates a debugging mode. activates a debugging mode.
Each member of the List identifies the intermediary that inserted the Each member of the List identifies the intermediary that inserted the
value and MUST have a type of either sf-string or sf-token. value and MUST have a type of either String (Section 3.3.3 of
[STRUCTURED-FIELDS]) or Token (Section 3.3.4 of [STRUCTURED-FIELDS]).
Depending on the deployment, this might be a service name (but not a Depending on the deployment, this might be a service name (but not a
software or hardware product name; e.g., "ExampleCDN" is appropriate, software or hardware product name; e.g., "ExampleCDN" is appropriate,
but "ExampleProxy" is not because it doesn't identify the but "ExampleProxy" is not because it doesn't identify the
deployment), a hostname ("proxy-3.example.com"), an IP address, or a deployment), a hostname ("proxy-3.example.com"), an IP address, or a
generated string. generated string.
Parameters of each member (per Section 3.1.2 of [STRUCTURED-FIELDS]) Parameters of each member (per Section 3.1.2 of [STRUCTURED-FIELDS])
convey additional information about that intermediary's handling of convey additional information about that intermediary's handling of
the response and its associated request; see Section 2.1. While all the response and its associated request; see Section 2.1. While all
of these parameters are OPTIONAL, intermediaries are encouraged to of these parameters are OPTIONAL, intermediaries are encouraged to
skipping to change at line 238 skipping to change at line 235
which would thereby allow a downstream recipient to understand that which would thereby allow a downstream recipient to understand that
processing by 'SomeOtherProxy' occurred before 'ThisProxy'. processing by 'SomeOtherProxy' occurred before 'ThisProxy'.
A client MAY promote the Proxy-Status trailer field into a header A client MAY promote the Proxy-Status trailer field into a header
field by following these steps: field by following these steps:
1. For each member trailer_member of the Proxy-Status trailer field 1. For each member trailer_member of the Proxy-Status trailer field
value: value:
1. Let header_member be the first (leftmost) value of the Proxy- 1. Let header_member be the first (leftmost) value of the Proxy-
Status header field value, comparing the sf-token or sf- Status header field value, comparing the String or Token
string character by character without consideration of character by character without consideration of parameters.
parameters.
2. If no matching header_member is found, continue processing 2. If no matching header_member is found, continue processing
the next trailer_member. the next trailer_member.
3. Replace header_member with trailer_member in its entirety, 3. Replace header_member with trailer_member in its entirety,
including any parameters. including any parameters.
2. Remove the Proxy-Status trailer field if empty. 2. Remove the Proxy-Status trailer field if empty.
2.1. Proxy-Status Parameters 2.1. Proxy-Status Parameters
This section lists parameters that can be used on the members of the This section lists parameters that can be used on the members of the
Proxy-Status field. Unrecognised parameters MUST be ignored. Proxy-Status field. Unrecognised parameters MUST be ignored.
2.1.1. error 2.1.1. error
The error parameter's value is an sf-token that is a proxy error The error parameter's value is a Token (Section 3.3.4 of
type. When present, it indicates that the intermediary encountered [STRUCTURED-FIELDS]) that is a proxy error type. When present, it
an issue when obtaining this response. indicates that the intermediary encountered an issue when obtaining
this response.
The presence of some proxy error types indicates that the response The presence of some proxy error types indicates that the response
was generated by the intermediary itself, rather than being forwarded was generated by the intermediary itself, rather than being forwarded
from the origin server. This is the case when, for example, the from the origin server. This is the case when, for example, the
origin server can't be contacted, so the proxy has to create its own origin server can't be contacted, so the proxy has to create its own
response. response.
Other proxy error types can be added to (potentially partial) Other proxy error types can be added to (potentially partial)
responses that were generated by the origin server or some other responses that were generated by the origin server or some other
inbound server. For example, if the forward connection abruptly inbound server. For example, if the forward connection abruptly
skipping to change at line 319 skipping to change at line 316
previous behaviours, a status code has already been sent) when previous behaviours, a status code has already been sent) when
another status code might be used. another status code might be used.
Proxy error types can also define any number of extra parameters for Proxy error types can also define any number of extra parameters for
use with that type. Their use, like all parameters, is optional. As use with that type. Their use, like all parameters, is optional. As
a result, if an extra parameter is used with a proxy error type for a result, if an extra parameter is used with a proxy error type for
which it is not defined, it will be ignored. which it is not defined, it will be ignored.
2.1.2. next-hop 2.1.2. next-hop
The next-hop parameter's value is an sf-string or sf-token that The next-hop parameter's value is a String (Section 3.3.3 of
identifies the intermediary or origin server selected (and used, if [STRUCTURED-FIELDS]) or Token (Section 3.3.4 of [STRUCTURED-FIELDS])
contacted) to obtain this response. It might be a hostname, IP that identifies the intermediary or origin server selected (and used,
if contacted) to obtain this response. It might be a hostname, IP
address, or alias. address, or alias.
For example: For example:
Proxy-Status: cdn.example.org; next-hop=backend.example.org:8001 Proxy-Status: cdn.example.org; next-hop=backend.example.org:8001
indicates that cdn.example.org used backend.example.org:8001 as the indicates that cdn.example.org used backend.example.org:8001 as the
next hop for this request. next hop for this request.
2.1.3. next-protocol 2.1.3. next-protocol
The next-protocol parameter's value indicates the Application-Layer The next-protocol parameter's value indicates the Application-Layer
Protocol Negotiation (ALPN) protocol identifier [RFC7301] of the Protocol Negotiation (ALPN) protocol identifier [RFC7301] of the
protocol used by the intermediary to connect to the next hop when protocol used by the intermediary to connect to the next hop when
obtaining this response. obtaining this response.
The value MUST be either an sf-token or sf-binary, representing a TLS The value MUST be either a Token (Section 3.3.4 of
ALPN Protocol ID (see <https://www.iana.org/assignments/tls- [STRUCTURED-FIELDS]) or Byte Sequence (Section 3.3.5 of
extensiontype-values/tls-extensiontype-values.xhtml#alpn-protocol- [STRUCTURED-FIELDS]), representing a TLS ALPN Protocol ID (see
ids>). If the protocol identifier is able to be expressed as an sf- <https://www.iana.org/assignments/tls-extensiontype-values/tls-
token using ASCII encoding, that form MUST be used. extensiontype-values.xhtml#alpn-protocol-ids>). If the protocol
identifier is able to be expressed as a Token using ASCII encoding,
that form MUST be used.
For example: For example:
Proxy-Status: "proxy.example.org"; next-protocol=h2 Proxy-Status: "proxy.example.org"; next-protocol=h2
Note that the ALPN identifier is being used here to identify the Note that the ALPN identifier is being used here to identify the
protocol in use; it may or may not have been actually used in the protocol in use; it may or may not have been actually used in the
protocol negotiation. protocol negotiation.
2.1.4. received-status 2.1.4. received-status
The received-status parameter's value indicates the HTTP status code The received-status parameter's value indicates the HTTP status code
that the intermediary received from the next-hop server when that the intermediary received from the next-hop server when
obtaining this response. obtaining this response.
The value MUST be an sf-integer. The value MUST be an Integer (Section 3.3.1 of [STRUCTURED-FIELDS]).
For example: For example:
Proxy-Status: ExampleCDN; received-status=200 Proxy-Status: ExampleCDN; received-status=200
2.1.5. details 2.1.5. details
The details parameter's value is an sf-string containing additional The details parameter's value is a String (Section 3.3.3 of
information not captured anywhere else. This can include [STRUCTURED-FIELDS]) containing additional information not captured
implementation-specific or deployment-specific information. anywhere else. This can include implementation-specific or
deployment-specific information.
For example: For example:
Proxy-Status: proxy.example.net; error="http_protocol_error"; Proxy-Status: proxy.example.net; error="http_protocol_error";
details="Malformed response header: space before colon" details="Malformed response header: space before colon"
2.2. Defining New Proxy-Status Parameters 2.2. Defining New Proxy-Status Parameters
New Proxy-Status parameters can be defined by registering them in the New Proxy-Status parameters can be defined by registering them in the
"HTTP Proxy-Status Parameters" registry. "HTTP Proxy-Status Parameters" registry.
skipping to change at line 408 skipping to change at line 409
parameters in the "HTTP Proxy Error Types" registry. parameters in the "HTTP Proxy Error Types" registry.
Registration requests should use the following template: Registration requests should use the following template:
Name: [a name for the Proxy-Status parameter that matches key] Name: [a name for the Proxy-Status parameter that matches key]
Description: [a description of the parameter semantics and value] Description: [a description of the parameter semantics and value]
Reference: [to a specification defining this parameter; optional] Reference: [to a specification defining this parameter; optional]
See the registry at <https://iana.org/assignments/http-proxy-status> See the registry at <https://www.iana.org/assignments/http-proxy-
for details on where to send registration requests. status> for details on where to send registration requests.
2.3. Proxy Error Types 2.3. Proxy Error Types
This section lists the proxy error types defined by this document. This section lists the proxy error types defined by this document.
See Section 2.4 for information about defining new proxy error types. See Section 2.4 for information about defining new proxy error types.
Note that implementations might not produce all proxy error types. Note that implementations might not produce all proxy error types.
The set of types below is designed to map to existing states in The set of types below is designed to map to existing states in
implementations and therefore may not be applicable to some. implementations and therefore may not be applicable to some.
skipping to change at line 444 skipping to change at line 445
2.3.2. DNS Error 2.3.2. DNS Error
Name: dns_error Name: dns_error
Description: The intermediary encountered a DNS error when trying to Description: The intermediary encountered a DNS error when trying to
find an IP address for the next-hop hostname. find an IP address for the next-hop hostname.
Extra Parameters: Extra Parameters:
rcode: An sf-string conveying the DNS RCODE that indicates the rcode: A String conveying the DNS RCODE that indicates the error
error type. See [RFC8499], Section 3. type. See [RFC8499], Section 3.
info-code: An sf-integer conveying the Extended DNS Error Code info-code: An Integer conveying the Extended DNS Error Code INFO-
INFO-CODE. See [RFC8914]. CODE. See [RFC8914].
Recommended HTTP Status Code: 502 Recommended HTTP Status Code: 502
Response Only Generated by Intermediaries: true Response Only Generated by Intermediaries: true
Reference: RFC 9209 Reference: RFC 9209
2.3.3. Destination Not Found 2.3.3. Destination Not Found
Name: destination_not_found Name: destination_not_found
skipping to change at line 657 skipping to change at line 658
2.3.15. TLS Alert Received 2.3.15. TLS Alert Received
Name: tls_alert_received Name: tls_alert_received
Description: The intermediary received a TLS alert from the next Description: The intermediary received a TLS alert from the next
hop. hop.
Extra Parameters: Extra Parameters:
alert-id: An sf-integer containing the applicable value from the alert-id: An Integer containing the applicable value from the
"TLS Alerts" registry. See [RFC8446]. "TLS Alerts" registry. See [RFC8446].
alert-message: An sf-token or sf-string containing the applicable alert-message: A Token or String containing the applicable
description string from the "TLS Alerts" registry. See description string from the "TLS Alerts" registry. See
[RFC8446]. [RFC8446].
Recommended HTTP Status Code: 502 Recommended HTTP Status Code: 502
Response Only Generated by Intermediaries: false Response Only Generated by Intermediaries: false
Reference: RFC 9209 Reference: RFC 9209
2.3.16. HTTP Request Error 2.3.16. HTTP Request Error
Name: http_request_error Name: http_request_error
Description: The intermediary is generating a client (4xx) response Description: The intermediary is generating a client (4xx) response
on the origin's behalf. Applicable status codes include (but are on the origin's behalf. Applicable status codes include (but are
not limited to) 400, 403, 405, 406, 408, 411, 413, 414, 415, 416, not limited to) 400, 403, 405, 406, 408, 411, 413, 414, 415, 416,
417, and 429. 417, and 429.
Extra Parameters: Extra Parameters:
status-code: An sf-integer containing the generated status code. status-code: An Integer containing the generated status code.
status-phrase: An sf-string containing the generated status status-phrase: A String containing the generated status phrase.
phrase.
Recommended HTTP Status Code: The applicable 4xx status code Recommended HTTP Status Code: The applicable 4xx status code
Response Only Generated by Intermediaries: true Response Only Generated by Intermediaries: true
Reference: RFC 9209 Reference: RFC 9209
Notes: This type helps distinguish between responses generated by Notes: This type helps distinguish between responses generated by
intermediaries from those generated by the origin. intermediaries from those generated by the origin.
skipping to change at line 735 skipping to change at line 735
2.3.19. HTTP Response Header Section Too Large 2.3.19. HTTP Response Header Section Too Large
Name: http_response_header_section_size Name: http_response_header_section_size
Description: The intermediary received a response to the request Description: The intermediary received a response to the request
whose header section was considered too large. whose header section was considered too large.
Extra Parameters: Extra Parameters:
header-section-size: An sf-integer indicating how large the header-section-size: An Integer indicating how large the received
received headers were. Note that they might not be complete; headers were. Note that they might not be complete; i.e., the
i.e., the intermediary may have discarded or refused additional intermediary may have discarded or refused additional data.
data.
Recommended HTTP Status Code: 502 Recommended HTTP Status Code: 502
Response Only Generated by Intermediaries: false Response Only Generated by Intermediaries: false
Reference: RFC 9209 Reference: RFC 9209
2.3.20. HTTP Response Header Field Line Too Large 2.3.20. HTTP Response Header Field Line Too Large
Name: http_response_header_size Name: http_response_header_size
Description: The intermediary received a response to the request Description: The intermediary received a response to the request
containing an individual header field line that was considered too containing an individual header field line that was considered too
large. large.
Extra Parameters: Extra Parameters:
header-name: An sf-string indicating the name of the header field header-name: A String indicating the name of the header field
that triggered the error. that triggered the error.
header-size: An sf-integer indicating the size of the header header-size: An Integer indicating the size of the header field
field that triggered the error. that triggered the error.
Recommended HTTP Status Code: 502 Recommended HTTP Status Code: 502
Response Only Generated by Intermediaries: false Response Only Generated by Intermediaries: false
Reference: RFC 9209 Reference: RFC 9209
2.3.21. HTTP Response Body Too Large 2.3.21. HTTP Response Body Too Large
Name: http_response_body_size Name: http_response_body_size
Description: The intermediary received a response to the request Description: The intermediary received a response to the request
whose body was considered too large. whose body was considered too large.
Extra Parameters: Extra Parameters:
body-size: An sf-integer indicating how large the received body body-size: An Integer indicating how large the received body was.
was. Note that it may not have been complete; i.e., the Note that it may not have been complete; i.e., the intermediary
intermediary may have discarded or refused additional data. may have discarded or refused additional data.
Recommended HTTP Status Code: 502 Recommended HTTP Status Code: 502
Response Only Generated by Intermediaries: false Response Only Generated by Intermediaries: false
Reference: RFC 9209 Reference: RFC 9209
2.3.22. HTTP Response Trailer Section Too Large 2.3.22. HTTP Response Trailer Section Too Large
Name: http_response_trailer_section_size Name: http_response_trailer_section_size
Description: The intermediary received a response to the request Description: The intermediary received a response to the request
whose trailer section was considered too large. whose trailer section was considered too large.
Extra Parameters: Extra Parameters:
trailer-section-size: An sf-integer indicating how large the trailer-section-size: An Integer indicating how large the
received trailers were. Note that they might not be complete; received trailers were. Note that they might not be complete;
i.e., the intermediary may have discarded or refused additional i.e., the intermediary may have discarded or refused additional
data. data.
Recommended HTTP Status Code: 502 Recommended HTTP Status Code: 502
Response Only Generated by Intermediaries: false Response Only Generated by Intermediaries: false
Reference: RFC 9209 Reference: RFC 9209
2.3.23. HTTP Response Trailer Field Line Too Large 2.3.23. HTTP Response Trailer Field Line Too Large
Name: http_response_trailer_size Name: http_response_trailer_size
Description: The intermediary received a response to the request Description: The intermediary received a response to the request
containing an individual trailer field line that was considered containing an individual trailer field line that was considered
too large. too large.
Extra Parameters: Extra Parameters:
trailer-name: An sf-string indicating the name of the trailer trailer-name: A String indicating the name of the trailer field
field that triggered the error. that triggered the error.
trailer-size: An sf-integer indicating the size of the trailer trailer-size: An Integer indicating the size of the trailer field
field that triggered the error. that triggered the error.
Recommended HTTP Status Code: 502 Recommended HTTP Status Code: 502
Response Only Generated by Intermediaries: false Response Only Generated by Intermediaries: false
Reference: RFC 9209 Reference: RFC 9209
2.3.24. HTTP Response Transfer-Coding Error 2.3.24. HTTP Response Transfer-Coding Error
Name: http_response_transfer_coding Name: http_response_transfer_coding
Description: The intermediary encountered an error decoding the Description: The intermediary encountered an error decoding the
transfer coding of the response. transfer coding of the response.
Extra Parameters: Extra Parameters:
coding: An sf-token containing the specific coding (from the coding: A Token containing the specific coding (from the "HTTP
"HTTP Transfer Coding Registry") that caused the error. Transfer Coding Registry") that caused the error.
Recommended HTTP Status Code: 502 Recommended HTTP Status Code: 502
Response Only Generated by Intermediaries: false Response Only Generated by Intermediaries: false
Reference: RFC 9209 Reference: RFC 9209
2.3.25. HTTP Response Content-Coding Error 2.3.25. HTTP Response Content-Coding Error
Name: http_response_content_coding Name: http_response_content_coding
Description: The intermediary encountered an error decoding the Description: The intermediary encountered an error decoding the
content coding of the response. content coding of the response.
Extra Parameters: Extra Parameters:
coding: An sf-token containing the specific coding (from the coding: A Token containing the specific coding (from the "HTTP
"HTTP Content Coding Registry") that caused the error. Content Coding Registry") that caused the error.
Recommended HTTP Status Code: 502 Recommended HTTP Status Code: 502
Response Only Generated by Intermediaries: false Response Only Generated by Intermediaries: false
Reference: RFC 9209 Reference: RFC 9209
2.3.26. HTTP Response Timeout 2.3.26. HTTP Response Timeout
Name: http_response_timeout Name: http_response_timeout
skipping to change at line 1000 skipping to change at line 999
specific, or deployment-specific values. If a generic value specific, or deployment-specific values. If a generic value
cannot be agreed upon in the community, the type's name should be cannot be agreed upon in the community, the type's name should be
correspondingly specific (e.g., with a prefix that identifies the correspondingly specific (e.g., with a prefix that identifies the
vendor, application, or deployment). vendor, application, or deployment).
* Extra parameters should not conflict with registered Proxy-Status * Extra parameters should not conflict with registered Proxy-Status
parameters. parameters.
Registration requests should use the following template: Registration requests should use the following template:
Name: [a name for the proxy error type that is of type sf-token] Name: [a name for the proxy error type that is of type Token
(Section 3.3.4 of [STRUCTURED-FIELDS])]
Description: [a description of the conditions that generate the Description: [a description of the conditions that generate the
proxy error type] proxy error type]
Extra Parameters: [zero or more optional parameters, along with Extra Parameters: [zero or more optional parameters, along with
their allowable type(s)] their allowable Structured Type(s)]
Recommended HTTP Status Code: [the appropriate HTTP status code for Recommended HTTP Status Code: [the appropriate HTTP status code for
this entry] this entry]
Response Only Generated by Intermediaries: ['true' or 'false'] Response Only Generated by Intermediaries: ['true' or 'false']
Reference: [to a specification defining this error type; optional] Reference: [to a specification defining this error type; optional]
Notes: [optional] Notes: [optional]
If the proxy error type might occur in responses that are not If the proxy error type might occur in responses that are not
generated by the intermediary -- for example, when an error is generated by the intermediary -- for example, when an error is
detected as the response is streamed from a forward connection, detected as the response is streamed from a forward connection,
causing a Proxy-Status trailer field to be appended -- the 'Response causing a Proxy-Status trailer field to be appended -- the 'Response
only generated by intermediaries' should be 'false'. If the proxy only generated by intermediaries' should be 'false'. If the proxy
error type only occurs in responses that are generated by the error type only occurs in responses that are generated by the
intermediary, it should be 'true'. intermediary, it should be 'true'.
See the registry at <https://iana.org/assignments/http-proxy-status> See the registry at <https://www.iana.org/assignments/http-proxy-
for details on where to send registration requests. status> for details on where to send registration requests.
3. IANA Considerations 3. IANA Considerations
IANA has created the "HTTP Proxy-Status Parameters" registry and the IANA has created the "HTTP Proxy-Status Parameters" registry and the
"HTTP Proxy Error Types" registry at "HTTP Proxy Error Types" registry at
<https://www.iana.org/assignments/http-proxy-status> and has <https://www.iana.org/assignments/http-proxy-status> and has
populated them with the types defined in Sections 2.1 and 2.3, populated them with the types defined in Sections 2.1 and 2.3
respectively; see Sections 2.2 and 2.4 for their associated respectively; see Sections 2.2 and 2.4 for their associated
procedures. procedures.
Additionally, the following entry has been added to the "Hypertext Additionally, the following entry has been added to the "Hypertext
Transfer Protocol (HTTP) Field Name Registry": Transfer Protocol (HTTP) Field Name Registry":
Field name: Proxy-Status Field name: Proxy-Status
Status: permanent Status: permanent
Specification document(s): RFC 9209 Specification document(s): RFC 9209
Comments: Comments:
skipping to change at line 1072 skipping to change at line 1072
generation of the field itself. Also, the field's content is not generation of the field itself. Also, the field's content is not
verified; an intermediary can claim certain actions (e.g., sending a verified; an intermediary can claim certain actions (e.g., sending a
request over an encrypted channel) but fail to actually do that. request over an encrypted channel) but fail to actually do that.
5. References 5. References
5.1. Normative References 5.1. Normative References
[HTTP] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke, [HTTP] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
Ed., "HTTP Semantics", RFC 9110, DOI 10.17487/RFC9110, Ed., "HTTP Semantics", RFC 9110, DOI 10.17487/RFC9110,
February 2022, <https://www.rfc-editor.org/info/rfc9110>. March 2022, <https://www.rfc-editor.org/info/rfc9110>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC7301] Friedl, S., Popov, A., Langley, A., and E. Stephan, [RFC7301] Friedl, S., Popov, A., Langley, A., and E. Stephan,
"Transport Layer Security (TLS) Application-Layer Protocol "Transport Layer Security (TLS) Application-Layer Protocol
Negotiation Extension", RFC 7301, DOI 10.17487/RFC7301, Negotiation Extension", RFC 7301, DOI 10.17487/RFC7301,
July 2014, <https://www.rfc-editor.org/info/rfc7301>. July 2014, <https://www.rfc-editor.org/info/rfc7301>.
skipping to change at line 1108 skipping to change at line 1108
Terminology", BCP 219, RFC 8499, DOI 10.17487/RFC8499, Terminology", BCP 219, RFC 8499, DOI 10.17487/RFC8499,
January 2019, <https://www.rfc-editor.org/info/rfc8499>. January 2019, <https://www.rfc-editor.org/info/rfc8499>.
[RFC8914] Kumari, W., Hunt, E., Arends, R., Hardaker, W., and D. [RFC8914] Kumari, W., Hunt, E., Arends, R., Hardaker, W., and D.
Lawrence, "Extended DNS Errors", RFC 8914, Lawrence, "Extended DNS Errors", RFC 8914,
DOI 10.17487/RFC8914, October 2020, DOI 10.17487/RFC8914, October 2020,
<https://www.rfc-editor.org/info/rfc8914>. <https://www.rfc-editor.org/info/rfc8914>.
[STRUCTURED-FIELDS] [STRUCTURED-FIELDS]
Nottingham, M. and P-H. Kamp, "Structured Field Values for Nottingham, M. and P-H. Kamp, "Structured Field Values for
HTTP", RFC 8941, DOI 10.17487/RFC8941, February 2021, HTTP", RFC 8941, DOI 10.17487/RFC8941, March 2021,
<https://www.rfc-editor.org/info/rfc8941>. <https://www.rfc-editor.org/info/rfc8941>.
5.2. Informative References 5.2. Informative References
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
<https://www.rfc-editor.org/info/rfc5234>.
[RFC8586] Ludin, S., Nottingham, M., and N. Sullivan, "Loop [RFC8586] Ludin, S., Nottingham, M., and N. Sullivan, "Loop
Detection in Content Delivery Networks (CDNs)", RFC 8586, Detection in Content Delivery Networks (CDNs)", RFC 8586,
DOI 10.17487/RFC8586, April 2019, DOI 10.17487/RFC8586, April 2019,
<https://www.rfc-editor.org/info/rfc8586>. <https://www.rfc-editor.org/info/rfc8586>.
Authors' Addresses Authors' Addresses
Mark Nottingham Mark Nottingham
Fastly Fastly
Prahran Prahran
 End of changes. 33 change blocks. 
74 lines changed or deleted 69 lines changed or added

This html diff was produced by rfcdiff 1.48. The latest version is available from http://tools.ietf.org/tools/rfcdiff/