Dear Friends, With Kamailio 3.1.2, after successfully registering, the caller sends INVITE to the proxy, and is always responded with 403 not relaying. I found that in the route[AUTH] subroutine, like below. Regarding the red comparing, it failed. I also check the code, and found Kamailio will use the host name in the From header to compare all the socket's IP address, such as host = mysipserver.com, but socket's ip = 127.0.0.1 or 10.1.1.5. As you can see, this comparing will never be equal.Could anyone show me how to handle this problem? Thanks a lot!         # authenticate if from local subscriber        if (from_uri==myself)        {            if (!proxy_authorize("$fd", "subscriber")) {                proxy_challenge("$fd", "0");                exit;            }            if (is_method("PUBLISH"))            {                if ($au!=$tU) {                    sl_send_reply("403","Forbidden auth ID");                    exit;                }            } else {                if ($au!=$fU) {                    sl_send_reply("403","Forbidden auth ID");                    exit;                }            }                consume_credentials();            # caller authenticated        } else {            # caller is not local subscriber, then check if it calls            # a local destination, otherwise deny, not an open relay here            if (!uri==myself)            {                sl_send_reply("403","Not relaying");                exit;            }        } Best Regards,Spencer