draft-ietf-httpbis-proxy-status-03.txt   draft-ietf-httpbis-proxy-status-04.txt 
HTTP M. Nottingham HTTP M. Nottingham
Internet-Draft Fastly Internet-Draft Fastly
Intended status: Standards Track P. Sikora Intended status: Standards Track P. Sikora
Expires: 13 August 2021 Google Expires: 13 August 2021 Google
9 February 2021 9 February 2021
The Proxy-Status HTTP Response Header Field The Proxy-Status HTTP Response Header Field
draft-ietf-httpbis-proxy-status-03 draft-ietf-httpbis-proxy-status-04
Abstract Abstract
This document defines the Proxy-Status HTTP field to convey the This document defines the Proxy-Status HTTP field to convey the
details of intermediary response handling, including generated details of intermediary response handling, including generated
errors. errors.
Note to Readers Note to Readers
_RFC EDITOR: please remove this section before publication_ _RFC EDITOR: please remove this section before publication_
skipping to change at page 2, line 28 skipping to change at page 2, line 28
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Notational Conventions . . . . . . . . . . . . . . . . . 4 1.1. Notational Conventions . . . . . . . . . . . . . . . . . 4
2. The Proxy-Status HTTP Field . . . . . . . . . . . . . . . . . 4 2. The Proxy-Status HTTP Field . . . . . . . . . . . . . . . . . 4
2.1. Proxy-Status Parameters . . . . . . . . . . . . . . . . . 5 2.1. Proxy-Status Parameters . . . . . . . . . . . . . . . . . 5
2.1.1. error . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1.1. error . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.2. next-hop . . . . . . . . . . . . . . . . . . . . . . 6 2.1.2. next-hop . . . . . . . . . . . . . . . . . . . . . . 6
2.1.3. next-protocol . . . . . . . . . . . . . . . . . . . . 7 2.1.3. next-protocol . . . . . . . . . . . . . . . . . . . . 7
2.2. received-status . . . . . . . . . . . . . . . . . . . . . 7 2.1.4. received-status . . . . . . . . . . . . . . . . . . . 7
2.2.1. details . . . . . . . . . . . . . . . . . . . . . . . 7 2.1.5. details . . . . . . . . . . . . . . . . . . . . . . . 7
2.3. Defining New Proxy-Status Parameters . . . . . . . . . . 7 2.2. Defining New Proxy-Status Parameters . . . . . . . . . . 7
2.4. Proxy Error Types . . . . . . . . . . . . . . . . . . . . 8 2.3. Proxy Error Types . . . . . . . . . . . . . . . . . . . . 8
2.4.1. DNS Timeout . . . . . . . . . . . . . . . . . . . . . 8 2.3.1. DNS Timeout . . . . . . . . . . . . . . . . . . . . . 8
2.4.2. DNS Error . . . . . . . . . . . . . . . . . . . . . . 8 2.3.2. DNS Error . . . . . . . . . . . . . . . . . . . . . . 8
2.4.3. Destination Not Found . . . . . . . . . . . . . . . . 9 2.3.3. Destination Not Found . . . . . . . . . . . . . . . . 9
2.4.4. Destination Unavailable . . . . . . . . . . . . . . . 9 2.3.4. Destination Unavailable . . . . . . . . . . . . . . . 9
2.4.5. Destination IP Prohibited . . . . . . . . . . . . . . 9 2.3.5. Destination IP Prohibited . . . . . . . . . . . . . . 9
2.4.6. Destination IP Unroutable . . . . . . . . . . . . . . 10 2.3.6. Destination IP Unroutable . . . . . . . . . . . . . . 10
2.4.7. Connection Refused . . . . . . . . . . . . . . . . . 10 2.3.7. Connection Refused . . . . . . . . . . . . . . . . . 10
2.4.8. Connection Terminated . . . . . . . . . . . . . . . . 10 2.3.8. Connection Terminated . . . . . . . . . . . . . . . . 10
2.4.9. Connection Timeout . . . . . . . . . . . . . . . . . 10 2.3.9. Connection Timeout . . . . . . . . . . . . . . . . . 10
2.4.10. Connection Read Timeout . . . . . . . . . . . . . . . 11 2.3.10. Connection Read Timeout . . . . . . . . . . . . . . . 11
2.4.11. Connection Write Timeout . . . . . . . . . . . . . . 11 2.3.11. Connection Write Timeout . . . . . . . . . . . . . . 11
2.4.12. Connection Limit Reached . . . . . . . . . . . . . . 11 2.3.12. Connection Limit Reached . . . . . . . . . . . . . . 11
2.4.13. TLS Protocol Error . . . . . . . . . . . . . . . . . 11 2.3.13. TLS Protocol Error . . . . . . . . . . . . . . . . . 11
2.4.14. TLS Certificate Error . . . . . . . . . . . . . . . . 12 2.3.14. TLS Certificate Error . . . . . . . . . . . . . . . . 12
2.4.15. TLS Alert Received . . . . . . . . . . . . . . . . . 12 2.3.15. TLS Alert Received . . . . . . . . . . . . . . . . . 12
2.4.16. HTTP Request Error . . . . . . . . . . . . . . . . . 13 2.3.16. HTTP Request Error . . . . . . . . . . . . . . . . . 13
2.4.17. HTTP Request Denied . . . . . . . . . . . . . . . . . 13 2.3.17. HTTP Request Denied . . . . . . . . . . . . . . . . . 13
2.4.18. HTTP Incomplete Response . . . . . . . . . . . . . . 13 2.3.18. HTTP Incomplete Response . . . . . . . . . . . . . . 13
2.4.19. HTTP Response Header Section Too Large . . . . . . . 14 2.3.19. HTTP Response Header Section Too Large . . . . . . . 14
2.4.20. HTTP Response Header Too Large . . . . . . . . . . . 14 2.3.20. HTTP Response Header Too Large . . . . . . . . . . . 14
2.4.21. HTTP Response Body Too Large . . . . . . . . . . . . 14 2.3.21. HTTP Response Body Too Large . . . . . . . . . . . . 14
2.4.22. HTTP Response Trailer Section Too Large . . . . . . . 15 2.3.22. HTTP Response Trailer Section Too Large . . . . . . . 15
2.4.23. HTTP Response Trailer Too Large . . . . . . . . . . . 15 2.3.23. HTTP Response Trailer Too Large . . . . . . . . . . . 15
2.4.24. HTTP Response Transfer-Coding Error . . . . . . . . . 16 2.3.24. HTTP Response Transfer-Coding Error . . . . . . . . . 16
2.4.25. HTTP Response Content-Coding Error . . . . . . . . . 16 2.3.25. HTTP Response Content-Coding Error . . . . . . . . . 16
2.4.26. HTTP Response Timeout . . . . . . . . . . . . . . . . 16 2.3.26. HTTP Response Timeout . . . . . . . . . . . . . . . . 16
2.4.27. HTTP Upgrade Failed . . . . . . . . . . . . . . . . . 17 2.3.27. HTTP Upgrade Failed . . . . . . . . . . . . . . . . . 17
2.4.28. HTTP Protocol Error . . . . . . . . . . . . . . . . . 17 2.3.28. HTTP Protocol Error . . . . . . . . . . . . . . . . . 17
2.4.29. Proxy Internal Response . . . . . . . . . . . . . . . 17 2.3.29. Proxy Internal Response . . . . . . . . . . . . . . . 17
2.4.30. Proxy Internal Error . . . . . . . . . . . . . . . . 17 2.3.30. Proxy Internal Error . . . . . . . . . . . . . . . . 17
2.4.31. Proxy Configuration Error . . . . . . . . . . . . . . 18 2.3.31. Proxy Configuration Error . . . . . . . . . . . . . . 18
2.4.32. Proxy Loop Detected . . . . . . . . . . . . . . . . . 18 2.3.32. Proxy Loop Detected . . . . . . . . . . . . . . . . . 18
2.5. Defining New Proxy Error Types . . . . . . . . . . . . . 18 2.4. Defining New Proxy Error Types . . . . . . . . . . . . . 18
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
4. Security Considerations . . . . . . . . . . . . . . . . . . . 19 4. Security Considerations . . . . . . . . . . . . . . . . . . . 19
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 20 5. References . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.1. Normative References . . . . . . . . . . . . . . . . . . 20 5.1. Normative References . . . . . . . . . . . . . . . . . . 20
5.2. Informative References . . . . . . . . . . . . . . . . . 20 5.2. Informative References . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21
1. Introduction 1. Introduction
HTTP intermediaries -- including both forward proxies and gateways HTTP intermediaries -- including both forward proxies and gateways
skipping to change at page 3, line 47 skipping to change at page 3, line 47
example, 502 Bad Gateway and 504 Gateway Timeout. However, example, 502 Bad Gateway and 504 Gateway Timeout. However,
experience has shown that more information is necessary to aid experience has shown that more information is necessary to aid
debugging and communicate what's happened to the client. debugging and communicate what's happened to the client.
Additionally, intermediaries sometimes want to convey additional Additionally, intermediaries sometimes want to convey additional
information about their handling of a response, even if they did not information about their handling of a response, even if they did not
generate it. generate it.
To enable these uses, Section 2 defines a new HTTP response field to To enable these uses, Section 2 defines a new HTTP response field to
allow intermediaries to convey details of their handling of a allow intermediaries to convey details of their handling of a
response, Section 2.1 enumerates the kind of information that can be response, Section 2.1 enumerates the kind of information that can be
conveyed, and Section 2.4 defines a set of error types for use when a conveyed, and Section 2.3 defines a set of error types for use when a
proxy encounters an issue when obtaining a response for the request. proxy encounters an issue when obtaining a response for the request.
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 BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
skipping to change at page 6, line 5 skipping to change at page 6, line 5
The "error" parameter's value is an sf-token that is a Proxy Error The "error" parameter's value is an sf-token that is a Proxy Error
Type. When present, it indicates that the proxy encountered an issue Type. When present, it indicates that the proxy encountered an issue
when obtaining a response. when obtaining a response.
Unless a Proxy Error Type specifies otherwise, the presences of error Unless a Proxy Error Type specifies otherwise, the presences of error
often, but not always, indicates that response was generated by the often, but not always, indicates that response was generated by the
proxy, not the origin server or any other upstream server. For proxy, not the origin server or any other upstream server. For
example, a proxy might attempt to correct an error, or part of a example, a proxy might attempt to correct an error, or part of a
response might be forwarded before the error is encountered. response might be forwarded before the error is encountered.
Section 2.4 lists the Proxy Error Types defined in this document; new Section 2.3 lists the Proxy Error Types defined in this document; new
ones can be defined using the procedure outlined in Section 2.5. ones can be defined using the procedure outlined in Section 2.4.
For example: For example:
HTTP/1.1 504 Gateway Timeout HTTP/1.1 504 Gateway Timeout
Proxy-Status: SomeCDN; error=connection_timeout Proxy-Status: SomeCDN; error=connection_timeout
indicates that this 504 response was generated by SomeCDN, due to a indicates that this 504 response was generated by SomeCDN, due to a
connection timeout when going forward. connection timeout when going forward.
Or: Or:
skipping to change at page 6, line 29 skipping to change at page 6, line 29
Proxy-Status: SomeReverseProxy; error=http_request_error Proxy-Status: SomeReverseProxy; error=http_request_error
indicates that this 429 Too Many Requests response was generated by indicates that this 429 Too Many Requests response was generated by
the intermediary, not the origin. the intermediary, not the origin.
When sending the error parameter, the most specific Proxy Error Type When sending the error parameter, the most specific Proxy Error Type
SHOULD be sent, provided that it accurately represents the error SHOULD be sent, provided that it accurately represents the error
condition. If an appropriate Proxy Error Type is not defined, there condition. If an appropriate Proxy Error Type is not defined, there
are a number of generic error types (e.g., proxy_internal_error, are a number of generic error types (e.g., proxy_internal_error,
http_protocol_error) that can be used. If they are not suitable, http_protocol_error) that can be used. If they are not suitable,
consider registering a new Proxy Error Type (see Section 2.5). consider registering a new Proxy Error Type (see Section 2.4).
Each Proxy Error Type has a Recommended HTTP Status Code. When Each Proxy Error Type has a Recommended HTTP Status Code. When
generating a HTTP response containing "error", its HTTP status code generating a HTTP response containing "error", its HTTP status code
SHOULD be set to the Recommended HTTP Status Code. However, there SHOULD be set to the Recommended HTTP Status Code. However, there
may be circumstances (e.g., for backwards compatibility with previous may be circumstances (e.g., for backwards compatibility with previous
behaviours, a status code has already been sent) when another status behaviours, a status code has already been sent) when another status
code might be used. 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
skipping to change at page 7, line 20 skipping to change at page 7, line 20
established. established.
The value MUST be either an sf-token or sf-binary. If the protocol The value MUST be either an sf-token or sf-binary. If the protocol
identifier is able to be expressed as an sf-token using UTF-8 identifier is able to be expressed as an sf-token using UTF-8
encoding, that form MUST be used. 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
2.2. received-status 2.1.4. received-status
The "received-status" parameter's value indicates the HTTP status The "received-status" parameter's value indicates the HTTP status
code that the intermediary received from the next hop server. code that the intermediary received from the next hop server.
The value MUST be an sf-integer. The value MUST be an sf-integer.
For example: For example:
Proxy-Status: ExampleProxy; received-status=200 Proxy-Status: ExampleProxy; received-status=200
2.2.1. details 2.1.5. details
The "details" parameter's value is an sf-string containing additional The "details" parameter's value is an sf-string containing additional
information not captured anywhere else. This can include information not captured anywhere else. This can include
implementation-specific or deployment-specific information. implementation-specific or deployment-specific information.
For example: For example:
Proxy-Status: ExampleProxy; error="http_protocol_error"; Proxy-Status: ExampleProxy; error="http_protocol_error";
details="Malformed response header - space before colon" details="Malformed response header - space before colon"
2.3. 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.
Registration requests are reviewed and approved by a Designated Registration requests are reviewed and approved by a Designated
Expert, as per [RFC8126], Section 4.5. A specification document is Expert, as per [RFC8126], Section 4.5. A specification document is
appreciated, but not required. appreciated, but not required.
The Expert(s) should consider the following factors when evaluating The Expert(s) should consider the following factors when evaluating
requests: requests:
skipping to change at page 8, line 30 skipping to change at page 8, line 30
* 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] * Reference: [to a specification defining this parameter]
See the registry at https://iana.org/assignments/http-proxy-status See the registry at https://iana.org/assignments/http-proxy-status
(https://iana.org/assignments/http-proxy-status) for details on where (https://iana.org/assignments/http-proxy-status) for details on where
to send registration requests. to send registration requests.
2.4. 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 2.5 for information about defining new Proxy Error Types. See Section 2.4 for information about defining new Proxy Error Types.
2.4.1. DNS Timeout 2.3.1. DNS Timeout
* Name: dns_timeout * Name: dns_timeout
* Description: The intermediary encountered a timeout when trying to * Description: The intermediary encountered a timeout when trying to
find an IP address for the next hop hostname. find an IP address for the next hop hostname.
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: 504 * Recommended HTTP status code: 504
2.4.2. DNS Error 2.3.2. DNS Error
* Name: dns_error * Name: dns_error
* Description: The intermediary encountered a DNS error when trying * Description: The intermediary encountered a DNS error when trying
to find an IP address for the next hop hostname. to find an IP address for the next hop hostname.
* Extra Parameters: * Extra Parameters:
- rcode: A sf-string conveying the DNS RCODE that indicates the - rcode: A sf-string conveying the DNS RCODE that indicates the
error type. See [RFC8499], Section 3. error type. See [RFC8499], Section 3.
* Recommended HTTP status code: 502 * Recommended HTTP status code: 502
2.4.3. Destination Not Found 2.3.3. Destination Not Found
* Name: destination_not_found * Name: destination_not_found
* Description: The intermediary cannot determine the appropriate * Description: The intermediary cannot determine the appropriate
next hop to use for this request; for example, it may not be next hop to use for this request; for example, it may not be
configured. Note that this error is specific to gateways, which configured. Note that this error is specific to gateways, which
typically require specific configuration to identify the "backend" typically require specific configuration to identify the "backend"
server; forward proxies use in-band information to identify the server; forward proxies use in-band information to identify the
origin server. origin server.
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: 500 * Recommended HTTP status code: 500
2.4.4. Destination Unavailable 2.3.4. Destination Unavailable
* Name: destination_unavailable * Name: destination_unavailable
* Description: The intermediary considers the next hop to be * Description: The intermediary considers the next hop to be
unavailable; e.g., recent attempts to communicate with it may have unavailable; e.g., recent attempts to communicate with it may have
failed, or a health check may indicate that it is down. failed, or a health check may indicate that it is down.
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: 503 * Recommended HTTP status code: 503
2.4.5. Destination IP Prohibited 2.3.5. Destination IP Prohibited
* Name: destination_ip_prohibited * Name: destination_ip_prohibited
* Description: The intermediary is configured to prohibit * Description: The intermediary is configured to prohibit
connections to the next hop IP address. connections to the next hop IP address.
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: 502 * Recommended HTTP status code: 502
2.4.6. Destination IP Unroutable 2.3.6. Destination IP Unroutable
* Name: destination_ip_unroutable * Name: destination_ip_unroutable
* Description: The intermediary cannot find a route to the next hop * Description: The intermediary cannot find a route to the next hop
IP address. IP address.
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: 502 * Recommended HTTP status code: 502
2.4.7. Connection Refused 2.3.7. Connection Refused
* Name: connection_refused * Name: connection_refused
* Description: The intermediary's connection to the next hop was * Description: The intermediary's connection to the next hop was
refused. refused.
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: 502 * Recommended HTTP status code: 502
2.4.8. Connection Terminated 2.3.8. Connection Terminated
* Name: connection_terminated * Name: connection_terminated
* Description: The intermediary's connection to the next hop was * Description: The intermediary's connection to the next hop was
closed before complete response was received. closed before complete response was received.
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: 502 * Recommended HTTP status code: 502
* Notes: Responses with this error type might not have been * Notes: Responses with this error type might not have been
generated by the intermediary. generated by the intermediary.
2.4.9. Connection Timeout 2.3.9. Connection Timeout
* Name: connection_timeout * Name: connection_timeout
* Description: The intermediary's attempt to open a connection to * Description: The intermediary's attempt to open a connection to
the next hop timed out. the next hop timed out.
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: 504 * Recommended HTTP status code: 504
2.4.10. Connection Read Timeout 2.3.10. Connection Read Timeout
* Name: connection_read_timeout * Name: connection_read_timeout
* Description: The intermediary was expecting data on a connection * Description: The intermediary was expecting data on a connection
(e.g., part of a response), but did not receive any new data in a (e.g., part of a response), but did not receive any new data in a
configured time limit. configured time limit.
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: 504 * Recommended HTTP status code: 504
* Notes: Responses with this error type might not have been * Notes: Responses with this error type might not have been
generated by the intermediary. generated by the intermediary.
2.4.11. Connection Write Timeout 2.3.11. Connection Write Timeout
* Name: connection_write_timeout * Name: connection_write_timeout
* Description: The intermediary was attempting to write data to a * Description: The intermediary was attempting to write data to a
connection, but was not able to (e.g., because its buffers were connection, but was not able to (e.g., because its buffers were
full). full).
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: 504 * Recommended HTTP status code: 504
* Notes: Responses with this error type might not have been * Notes: Responses with this error type might not have been
generated by the intermediary. generated by the intermediary.
2.4.12. Connection Limit Reached 2.3.12. Connection Limit Reached
* Name: connection_limit_reached * Name: connection_limit_reached
* Description: The intermediary is configured to limit the number of * Description: The intermediary is configured to limit the number of
connections it has to the next hop, and that limit has been connections it has to the next hop, and that limit has been
passed. passed.
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: 503 * Recommended HTTP status code: 503
2.4.13. TLS Protocol Error 2.3.13. TLS Protocol Error
* Name: tls_protocol_error * Name: tls_protocol_error
* Description: The intermediary encountered a TLS error when * Description: The intermediary encountered a TLS error when
communicating with the next hop, either during handshake or communicating with the next hop, either during handshake or
afterwards. afterwards.
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: 502 * Recommended HTTP status code: 502
* Notes: Responses with this error type might not have been * Notes: Responses with this error type might not have been
generated by the intermediary. generated by the intermediary.
Note that additional information about the error can be recorded in Note that additional information about the error can be recorded in
the details parameter (as is the case for all errors). the details parameter (as is the case for all errors).
2.4.14. TLS Certificate Error 2.3.14. TLS Certificate Error
* Name: tls_certificate_error * Name: tls_certificate_error
* Description: The intermediary encountered an error when verifying * Description: The intermediary encountered an error when verifying
the certificate presented by the next hop. the certificate presented by the next hop.
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: 502 * Recommended HTTP status code: 502
Note that additional information about the error can be recorded in Note that additional information about the error can be recorded in
the details parameter (as is the case for all errors). the details parameter (as is the case for all errors).
2.4.15. 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-message: an sf-token containing the applicable - alert-message: an sf-token containing the applicable
description string from the TLS Alerts registry. description string from the TLS Alerts registry.
* Recommended HTTP status code: 502 * Recommended HTTP status code: 502
* Notes: Responses with this error type might not have been * Notes: Responses with this error type might not have been
generated by the intermediary. generated by the intermediary.
2.4.16. 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) * Description: The intermediary is generating a client (4xx)
response on the origin's behalf. Applicable status codes include response on the origin's behalf. Applicable status codes include
(but are not limited to) 400, 403, 405, 406, 408, 411, 413, 414, (but are not limited to) 400, 403, 405, 406, 408, 411, 413, 414,
415, 416, 417, 429. 415, 416, 417, 429.
* Extra Parameters: * Extra Parameters:
skipping to change at page 13, line 27 skipping to change at page 13, line 27
code. code.
- status-phrase: an sf-string containing the generated status - status-phrase: an sf-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
* 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.
2.4.17. HTTP Request Denied 2.3.17. HTTP Request Denied
* Name: http_request_denied * Name: http_request_denied
* Description: The intermediary rejected the HTTP request based on * Description: The intermediary rejected the HTTP request based on
its configuration and/or policy settings. The request wasn't its configuration and/or policy settings. The request wasn't
forwarded to the next hop. forwarded to the next hop.
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: 403 * Recommended HTTP status code: 403
2.4.18. HTTP Incomplete Response 2.3.18. HTTP Incomplete Response
* Name: http_response_incomplete * Name: http_response_incomplete
* Description: The intermediary received an incomplete response to * Description: The intermediary received an incomplete response to
the request from the next hop. the request from the next hop.
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: 502 * Recommended HTTP status code: 502
* Notes: Responses with this error type might not have been * Notes: Responses with this error type might not have been
generated by the intermediary. generated by the intermediary.
2.4.19. 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 sf-integer indicating how large the
headers received were. Note that they might not be complete; headers received 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
* Notes: Responses with this error type might not have been * Notes: Responses with this error type might not have been
generated by the intermediary. generated by the intermediary.
2.4.20. HTTP Response Header Too Large 2.3.20. HTTP Response Header 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 line that was considered too containing an individual header line that was considered too
large. large.
* Extra Parameters: * Extra Parameters:
- header-name: an sf-string indicating the name of the header - header-name: an sf-string indicating the name of the header
that triggered the error. that triggered the error.
- header-size: an sf-integer indicating the size of the header - header-size: an sf-integer indicating the size of the header
that triggered the error. that triggered the error.
* Recommended HTTP status code: 502 * Recommended HTTP status code: 502
* Notes: Responses with this error type might not have been * Notes: Responses with this error type might not have been
generated by the intermediary. generated by the intermediary.
2.4.21. 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 body received - body-size: an sf-integer indicating how large the body received
was. Note that it may not have been complete; i.e., the was. Note that it may not have been complete; i.e., the
intermediary may have discarded or refused additional data. intermediary may have discarded or refused additional data.
* Recommended HTTP status code: 502 * Recommended HTTP status code: 502
* Notes: Responses with this error type might not have been * Notes: Responses with this error type might not have been
generated by the intermediary. generated by the intermediary.
2.4.22. 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 sf-integer indicating how large the
trailers received were. Note that they might not be complete; trailers received 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
* Notes: Responses with this error type might not have been * Notes: Responses with this error type might not have been
generated by the intermediary. generated by the intermediary.
2.4.23. HTTP Response Trailer Too Large 2.3.23. HTTP Response Trailer 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 line that was considered too containing an individual trailer line that was considered too
large. large.
* Extra Parameters: * Extra Parameters:
- trailer-name: an sf-string indicating the name of the trailer - trailer-name: an sf-string indicating the name of the trailer
that triggered the error. that triggered the error.
- trailer-size: an sf-integer indicating the size of the trailer - trailer-size: an sf-integer indicating the size of the trailer
that triggered the error. that triggered the error.
* Recommended HTTP status code: 502 * Recommended HTTP status code: 502
* Notes: Responses with this error type might not have been * Notes: Responses with this error type might not have been
generated by the intermediary. generated by the intermediary.
2.4.24. 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 that caused - coding: an sf-token containing the specific coding that caused
the error. the error.
* Recommended HTTP status code: 502 * Recommended HTTP status code: 502
* Notes: Responses with this error type might not have been * Notes: Responses with this error type might not have been
generated by the intermediary. generated by the intermediary.
2.4.25. 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 that caused - coding: an sf-token containing the specific coding that caused
the error. the error.
* Recommended HTTP status code: 502 * Recommended HTTP status code: 502
* Notes: Responses with this error type might not have been * Notes: Responses with this error type might not have been
generated by the intermediary. generated by the intermediary.
2.4.26. HTTP Response Timeout 2.3.26. HTTP Response Timeout
* Name: http_response_timeout * Name: http_response_timeout
* Description: The intermediary reached a configured time limit * Description: The intermediary reached a configured time limit
waiting for the complete response. waiting for the complete response.
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: 504 * Recommended HTTP status code: 504
* Notes: Responses with this error type might not have been * Notes: Responses with this error type might not have been
generated by the intermediary. generated by the intermediary.
2.4.27. HTTP Upgrade Failed 2.3.27. HTTP Upgrade Failed
* Name: http_upgrade_failed * Name: http_upgrade_failed
* Description: The HTTP Upgrade between the intermediary and the * Description: The HTTP Upgrade between the intermediary and the
next hop failed. next hop failed.
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: 502 * Recommended HTTP status code: 502
2.4.28. HTTP Protocol Error 2.3.28. HTTP Protocol Error
* Name: http_protocol_error * Name: http_protocol_error
* Description: The intermediary encountered a HTTP protocol error * Description: The intermediary encountered a HTTP protocol error
when communicating with the next hop. This error should only be when communicating with the next hop. This error should only be
used when a more specific one is not defined. used when a more specific one is not defined.
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: 502 * Recommended HTTP status code: 502
* Notes: Responses with this error type might not have been * Notes: Responses with this error type might not have been
generated by the intermediary. generated by the intermediary.
Note that additional information about the error can be recorded in Note that additional information about the error can be recorded in
the details parameter (as is the case for all errors). the details parameter (as is the case for all errors).
2.4.29. Proxy Internal Response 2.3.29. Proxy Internal Response
* Name: proxy_internal_response * Name: proxy_internal_response
* Description: The intermediary generated the response locally, * Description: The intermediary generated the response locally,
without attempting to connect to the next hop (e.g. in response to without attempting to connect to the next hop (e.g. in response to
a request to a debug endpoint terminated at the intermediary). a request to a debug endpoint terminated at the intermediary).
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: * Recommended HTTP status code:
2.4.30. Proxy Internal Error 2.3.30. Proxy Internal Error
* Name: proxy_internal_error * Name: proxy_internal_error
* Description: The intermediary encountered an internal error * Description: The intermediary encountered an internal error
unrelated to the origin. unrelated to the origin.
* Extra Parameters: None * Extra Parameters: None
* Recommended HTTP status code: 500 * Recommended HTTP status code: 500
Note that additional information about the error can be recorded in Note that additional information about the error can be recorded in
the details parameter (as is the case for all errors). the details parameter (as is the case for all errors).
2.4.31. Proxy Configuration Error 2.3.31. Proxy Configuration Error
* Name: proxy_configuration_error * Name: proxy_configuration_error
* Description: The intermediary encountered an error regarding its * Description: The intermediary encountered an error regarding its
configuration. configuration.
* Extra Parameters: None * Extra Parameters: None
* Recommended HTTP status code: 500 * Recommended HTTP status code: 500
Note that additional information about the error can be recorded in Note that additional information about the error can be recorded in
the details parameter (as is the case for all errors). the details parameter (as is the case for all errors).
2.4.32. Proxy Loop Detected 2.3.32. Proxy Loop Detected
* Name: proxy_loop_detected * Name: proxy_loop_detected
* Description: The intermediary tried to forward the request to * Description: The intermediary tried to forward the request to
itself, or a loop has been detected using different means (e.g. itself, or a loop has been detected using different means (e.g.
[RFC8586]). [RFC8586]).
* Extra Parameters: None. * Extra Parameters: None.
* Recommended HTTP status code: 502 * Recommended HTTP status code: 502
2.5. Defining New Proxy Error Types 2.4. Defining New Proxy Error Types
New Proxy Error Types can be defined by registering them in the HTTP New Proxy Error Types can be defined by registering them in the HTTP
Proxy Error Types registry. Proxy Error Types registry.
Registration requests are reviewed and approved by a Designated Registration requests are reviewed and approved by a Designated
Expert, as per [RFC8126], Section 4.5. A specification document is Expert, as per [RFC8126], Section 4.5. A specification document is
appreciated, but not required. appreciated, but not required.
The Expert(s) should consider the following factors when evaluating The Expert(s) should consider the following factors when evaluating
requests: requests:
skipping to change at page 19, line 43 skipping to change at page 19, line 43
See the registry at https://iana.org/assignments/http-proxy-status See the registry at https://iana.org/assignments/http-proxy-status
(https://iana.org/assignments/http-proxy-status) for details on where (https://iana.org/assignments/http-proxy-status) for details on where
to send registration requests. to send registration requests.
3. IANA Considerations 3. IANA Considerations
Upon publication, please create the HTTP Proxy-Status Parameters Upon publication, please create the HTTP Proxy-Status Parameters
registry and the HTTP Proxy Error Types registry at registry and the HTTP Proxy Error Types registry at
https://iana.org/assignments/http-proxy-statuses https://iana.org/assignments/http-proxy-statuses
(https://iana.org/assignments/http-proxy-statuses) and populate them (https://iana.org/assignments/http-proxy-statuses) and populate them
with the types defined in Section 2.1 and Section 2.4 respectively; with the types defined in Section 2.1 and Section 2.3 respectively;
see Section 2.3 and Section 2.5 for its associated procedures. see Section 2.2 and Section 2.4 for its associated procedures.
4. Security Considerations 4. Security Considerations
One of the primary security concerns when using Proxy-Status is One of the primary security concerns when using Proxy-Status is
leaking information that might aid an attacker. For example, leaking information that might aid an attacker. For example,
information about the intermediary's configuration and back-end information about the intermediary's configuration and back-end
topology can be exposed. topology can be exposed.
As a result, care needs to be taken when deciding to generate a As a result, care needs to be taken when deciding to generate a
Proxy-Status field. Note that intermediaries are not required to Proxy-Status field. Note that intermediaries are not required to
 End of changes. 44 change blocks. 
82 lines changed or deleted 82 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/