Manual:Hooks/IsTrustedProxy

Details

 * $ip - The IP address of the proxy.
 * $trusted - A bool indicating the IP is or isn't trusted.

Modifies the behavior of ; this is more or less the dynamic equivalent of setting $wgSquidServers. It mainly means that when a request coming from this IP tells (via the  header) that the real source of the request is some other IP, MediaWiki will trust that claim.