Use Proxy

Overview

305 Use Proxy was defined to mean the requested resource must be accessed through the proxy given in the Location header. However, it is deprecated for security reasons, and modern browsers and clients do not obey it.

Because a malicious server could force a client onto an arbitrary proxy and intercept traffic, it survives only as a historical code that is not used in practice.

When it happens

• It was originally defined to force requests through a particular proxy, but it is effectively unused today.
• If you encounter it, it usually reflects a stale configuration or a misimplemented server.

Request / Response example

GET /resource HTTP/1.1
Host: example.com

HTTP/1.1 305 Use Proxy
Location: http://proxy.example.com:8080

(deprecated: modern clients ignore this)

In code

HTTP/1.1 305 Use Proxy
Location: http://proxy.example.com:8080

Notes

• Owing to the security vulnerability, major browsers are implemented to ignore 305.
• If a proxy is required, the correct approach is an explicit client/OS proxy configuration or a PAC file, not 305.

Related status codes

Related headers

Specification