Use SER nathelper module and rtpproxy. Use SIP ping from SER every few seconds (not too sparse, because NAT will close; but not too frequent either - use 8 seconds). If your device is capable of it - use SIP ping and RTP/RTCP ping every 8 seconds.
-- Regards, Arek Bekiersz
Istvan De wrote:
Hi!
I've read about the above topic in the arcives and now I've got the same problem.
User A is behind a symmetric NAT -> a new port is bound for every different (external ip, external port) pair. User B has a connection to the net without any NAT or firewall.
User A wants to have a SIP+RTP session with user B. How?
I guess basically what is needed is forming of a SIP message like "send the your reply to the same ip and same port from where you have received this" and user A can send this to user B.
For the RTP session, a pretty similar thing would be needed like, A says to B: "I send you the RTP stream on your x port, send your rtp stream back to the same ip and port from where you receive mine".
How to setup such a SIP packet? Or maybe there is a standard solution for this already? (STUN wont help in this case I guess, and TURN is not an option for me.)
I've read about "symmetric SIP + symmetric RTP" maybe that is the same as I've described above?