Via

The Via general header is added by proxies, both forward and reverse proxies, and can appear in the request headers and the response headers. It is used for tracking message forwards, avoiding request loops, and identifying the protocol capabilities of senders along the request/response chain.

Syntax

Via: [ <protocol-name> "/" ] <protocol-version> <host> [ ":" <port> ]
or
Via: [ <protocol-name> "/" ] <protocol-version> <pseudonym>

Directives

<protocol-name>

Optional. The name of the protocol used, such as "HTTP".

<protocol-version>

The version of the protocol used, such as "1.1".

<host> and <port>

Public proxy URL and port.

<pseudonym>

Name/alias of an internal proxy.

Examples

Via: 1.1 vegur
Via: HTTP/1.1 GWA
Via: 1.0 fred, 1.1 p.example.net

Specifications

Browser compatibilityUpdate compatibility data on GitHub

See also

• X-Forwarded-For
• Heroku's proxy library Vegur