Hello, in kazoo is there a way to force symmetric RTP? I have a client who's behind a NAT and when they send an invite the SDP contains the private IP and port, but their router is doing NAT translation so the RTP goes out through a different port. I can see through a packet capture that freeswitch is trying to send RTP to the SDP port instead of the port it was received from.

The weird thing is that it works in other cases where the SDP port is the same as this one and the device is on the same private subnet, so there seems to be something about this device or account that is not set correctly, because I don't see any significant differences in the SIP trace

nlogex there are some Kamailio settings you could mess with---I thought symmetric was the default, but it's possible that only applies in certain cases.

Also, look in your Kamailio logs---it should be telling you details about what it's doing with the NAT when that happens.

nlogex and make sure you have NAT_TRAVERSAL_ROLE enabled in your local.cfg

If it's already enabled, the settings for config on that are in /etc/kazoo/kamailio/nat-traversal-role.cfg and the module documentation is here: kamailio.org/docs/modules/5.5.x/modules/nathelper.html

Thanks, I do have NAT_TRAVERSAL_ROLE enabled and it works for most devices behind NAT, but not for this one and I can't figure out why not. On the other devices, I noticed freeswitch is sending a SIP UPDATE after the first 200 OK (with SDP) received from the device and then it prints "Auto Changing audio port from <privateip:port> to <publicip:port>" but it doesn't do that for this device...