If you see requests like: "GET http://somesite/proxycheck.php http://somesite/proxycheck.php Try this in Nginx server config: if ($request ~* "^[^ ]+[ ]+[^:]+:

If you see requests like: "GET http://somesite/proxycheck.php http://somesite/proxycheck.php Try this in Nginx server config: if ($request ~* "^[^ ]+[ ]+[^:]+://" ) { return 444; } 444 is nonstandard Nginx code that closes the connection without sending any headers.