Hello,

I have a problem with my basic Kamailio setup using RTPengine. I'm testing initially with two client UAs in the same LAN as the SIP server behind the firewall. The initiating UA starts the media proxy as soon as the receiving UA accepts the call, indicated by the call timer starting. But after accepting the call the receiving UA's timer doesn't start and after 10-15 secs hangs up with a NO ACK error message.

I am using the kamailio default config file that comes with the Debian package and have made minimal changes recommended by various How-Tos for using Kamailio behind a firewall. Because the clients can successfully register over TLS, I'm assuming the problem is in the rtpengine configuration. The two rtp listen parameters I've tried are:

interface = internal/192.168.1.100;external/192.168.1.100!myproxyname.domain.net --or-- interface = internal/192.168.1.100;external/myproxyname.domain.net listen-ng = localhost:2223

I'm not sure why some example rtpengine configs list both the private and public addresses as external.

Any suggestions where to start troubleshooting?

Thanks,

Steve