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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

Specification Title
RFC 7230, section 5.7.1: Via Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing

Browser compatibility

Feature Chrome Firefox Edge Internet Explorer Opera Safari
Basic Support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)
Feature Android Chrome for Android Edge mobile Firefox for Android IE mobile Opera Android iOS Safari
Basic Support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)

See also

© 2005–2017 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Via