I am trying Asterisk SRTP in my environment, and find that when Asterisk is behind a NAT, the audi/video UDP ports opened for SRTP relay by Asterisk are local ports on the Asterisk server, media from the two clients out of the NAT (for example from Internet) can not reach the ports, and thus the two client can not establish the secure call via Asterisk. I have set up a STUN server and configured in rtp.conf, but seems Asterisk does not do STUN
before it opens ports for SRTP. BTW, Non-SRTP call can work though.
Anyone can give advice on how to make SRTP work in such an env?
Thanks a lot in advance!