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.
| Header type | General header |
|---|---|
| Forbidden header name | yes |
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
The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.