305 Use Proxy

What it means

HTTP 305 Use Proxy was meant to tell a client that the requested resource is only available through a proxy named in the response. Browsers never implemented it properly, and because it could be abused to silently route traffic through an attacker's proxy, it was deprecated for security reasons. You should treat it as obsolete.

When it happens

In practice it almost never happens. A misconfigured or very old server might emit it, but modern browsers ignore it and no current software relies on it.

How to fix it

• Do not use 305 — it is deprecated and unsupported by browsers.
• If a server returns it, reconfigure that server to use a normal redirect or proper proxy settings instead.
• Configure proxies through client or network settings rather than an HTTP status.

SEO impact

None in any useful sense. Crawlers ignore it, so a page depending on 305 simply will not be reached or indexed.