I have a phone behind a firewall registering with the internal profile. The address in the Via header is not reachable, and the FS (correctly, IMO) sends the response back to the actual sending IP address. However, rather than sending it to the actual sending udp port, it incorrectly (again, IMO) sends it to the port advertised in the Via header. Of course the message does not get through the firewall, and the phone keeps retransmitting the REGISTER. Is this a bug, or am I missing something? And is there a setting where I can force the behavior that I want (which is: send responses to the sending address:port if the sending address:port is different than the Via header). Trace below.. recv 481 bytes from udp/[66.37.97.53]:1024 at 19:28:12.445081: ------------------------------------------------------------------------ REGISTER sip:65.162.239.204 SIP/2.0 Via: SIP/2.0/UDP 10.93.14.119:5064;branch=z9hG4bK-e73de4bf From: "1002" <sip:1002@65.162.239.204>;tag=7718f2af7f3dcc73o2 To: "1002" <sip:1002@65.162.239.204> Call-ID: 930c7e31-648ae3db@10.93.14.119 CSeq: 53622 REGISTER Max-Forwards: 70 Contact: "1002" <sip:1002@10.93.14.119:5064>;expires=3600 User-Agent: Linksys/SPA962-5.2.8(SC) Content-Length: 0 Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, REFER Supported: replaces ------------------------------------------------------------------------ send 671 bytes to udp/[66.37.97.53]:5064 at 19:28:12.445259: ------------------------------------------------------------------------ SIP/2.0 401 Unauthorized Via: SIP/2.0/UDP 10.93.14.119:5064;branch=z9hG4bK-e73de4bf;received=66.37.97.53 From: "1002" <sip:1002@65.162.239.204>;tag=7718f2af7f3dcc73o2 To: "1002" <sip:1002@65.162.239.204>;tag=t1m9emDKB4trF Call-ID: 930c7e31-648ae3db@10.93.14.119 CSeq: 53622 REGISTER User-Agent: FreeSWITCH-mod_sofia/1.0.head-git-25c725c 2011-06-30 18-30-24 -0500 Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, UPDATE, INFO, REGISTER, REFER, NOTIFY, PUBLISH, SUBSCRIBE Supported: timer, precondition, path, replaces WWW-Authenticate: Digest realm="65.162.239.204", nonce="7e426985-2f7a-40ff-a817-6c167207853f", algorithm=MD5, qop="auth" Content-Length: 0