HI all, I have a NAT problem I can't seem to get past. The phone is NATed. From my location with a FIOS router it works fine. But the client recently upgraded to a new SonicWall router and splat, this device failed. There are about 10 Cisco phones at this location working fine. This phone is a Panasonic KX-TGP550. I have poured over the sip logs and identified the problem. The sip packets come from the router IP and port 15xxx but are returned to that IP and the phone's source port 5060 instead of 15xxx. I have tried every NDLB feature I can find, but not every combination. The responses always go back to the wrong port. Any help would be greatly appreciated. Thanks, Sean Sample sip dump: ------------------------------------------------------------------------ recv 492 bytes from udp/[98.204.241.22]:15183 at 23:16:33.764217: ------------------------------------------------------------------------ REGISTER sip:XYZ.bizfocused.com:5060 SIP/2.0 Via: SIP/2.0/UDP 192.168.2.109:5074;branch=z9hG4bKb6be703b Max-Forwards: 70 To: <sip:34@XYZ.bizfocused.com> From: <sip:34@XYZ.bizfocused.com>;tag=3263080642 Call-ID: 97742e94-d1dc14228bad9baadd810080f041d179@192.168.2.109<mailto:97742e94-d1dc14228bad9baadd810080f041d179@192.168.2.109> CSeq: 1 REGISTER Contact: <sip:34@192.168.2.109:5074> Expires: 3600 Allow: INVITE,ACK,CANCEL,BYE,OPTIONS,NOTIFY,REFER,UPDATE User-Agent: Panasonic_KX-TGP550T04/13.33 (0080f041d179) Content-Length: 0 ------------------------------------------------------------------------ send 669 bytes to udp/[98.204.241.22]:5074 at 23:16:33.764394: ------------------------------------------------------------------------ SIP/2.0 401 Unauthorized