On 03.01.2014 16:59, Brian Davis wrote:

REGISTER sip:test1.test.com:5060 SIP/2.0
Via: SIP/2.0/UDP 96.xxx.xxx.xxx:33745;rport;branch=z9hG4bKf5s1p`n3TRv5TZx5RXy.RVv+JPz8Nat*UX!8KRx4SRx
Via: SIP/2.0/UDP 192.xx.xxx.xxx:33745;branch=z9hG4bKeb263246c44095f072d8167dd0c7987a343134;rport
Contact: "Joe" <sip:xxxyyyzzzz@192.xx.xxx.xxx:33745;transport=udp>

Dec 30 03:33:45 sip-01 kamailio[20489]: INFO: <script>: 3b0400ca43e28f78f3e6dc945a084b88@192.xx.xxx.xxx|log|source 96.xxx.xxx.xxx:33745

Actually the source IP seem to be identical to the topmost Via address.

But it should detect the private IP address in the contact header.

Maybe you have an exception, that NAT traversal is not triggered, if there is more than 1 Via header.

Klaus