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