I think maybe this can help you: http://lists.iptel.org/pipermail/serusers/2004-November/013540.html
At the bottom of the post there is a link to an rtpproxy patch for behind-NAT operation. g-)
Giovanni Balasso wrote:
Hi serusers, after reading lots of docs and mailing lists I still have some doubts about nathelper+rtpproxy and the error message I usually get from it is
rtpproxy: can't bind to the IPv4 port 35000: Cannot assign requested address
what is the correct way to start rtpproxy? do I have to provide nat and public ip?
In the following situation: machine behind nat with private IP, running ser and reachable from the outside via port forwarding on router's public ip (forwarding port 5060 for ser and ports 35000-.... for rtpproxy range, both udp/tcp), can I use rtpproxy? how should i start it? (in the above situation ser registration from the outside works!)
thanks in advance