php获得ip，真实IP

    function getIP(){
        global $ip;
        if (getenv("HTTP_CLIENT_IP"))
            $ip = getenv("HTTP_CLIENT_IP");
        else if(getenv("HTTP_X_FORWARDED_FOR"))
            $ip = getenv("HTTP_X_FORWARDED_FOR");
        else if(getenv("REMOTE_ADDR"))
            $ip = getenv("REMOTE_ADDR");
        else $ip = "Unknow";
        return $ip;
    }

调用：getIP();