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  1. HTTP (Hypertext Transfer Protocol)
  1. HTTP Headers
  1. Proxy-Authenticate
      1. Writing responses (servers)
      2. Reading responses (clients)
    1. Overview table
    2. Syntax
      1. Example
    3. History

Proxy-Authenticate

The "Proxy-Authenticate" header field consists of at least one challenge that indicates the authentication scheme(s) and parameters applicable to the proxy for this effective request URI (Section 5.5 of [RFC7230]). A proxy MUST send at least one Proxy-Authenticate header field in each 407 (Proxy Authentication Required) response that it generates.

Writing responses (servers)

Reading responses (clients)

The request should be retried with a Proxy-Authorization header.

Overview table

Name
Proxy-Authenticate
Description
Requests the user-agent authenticate to an intermediate proxy.
Direction
Response
Advertises
Proxy-Authorization
Specification
RFC 9110: HTTP Semantics §11.7.1. Proxy-Authenticate

Syntax

Proxy-Authenticate = 1#challenge
challenge   = auth-scheme [ 1*SP ( token68 / #auth-param ) ]
auth-scheme    = token
auth-param = token BWS "=" BWS ( token / quoted-string )
token68 = 1*( ALPHA / DIGIT / "-" / "." / "_" / "~" / "+" / "/" ) *"="

auth-scheme is one of the registered values in the Authentication Scheme Registry.

Example

Proxy-Authenticate: Basic realm="gateway"

History

  1. 1999-06: RFC 2616 §14.33. Proxy-Authenticate
  2. 2014-06: RFC 7235 §4.3. Proxy-Authenticate. This header was split out from the core document.
  3. 2022-06: RFC 9110 §11.7.1. Proxy-Authenticate. Moved back into HTTP Semantics.