Hi there

When someone calls to num_msk, it shoot to port 5070. Call is received, but is rejected after 30 seconds by timeout (not received ACK on 200 OK). I think it's because FS sends 200 OK with port number = 0 in field Contact. All another headers are good (it seems).

In the profile check the value of ext-sip-ip is not stun or auto-nat as this could result in the 0 port number if the discovery fails (just a guess on my part). Better to set it to auto or the actual IP address.

Does someone know how to say FS to use correct port number in field Contact in 200 OK?

If the suggestion above does not work there is an undocumented profile parameter of ext-sip-port so you could try that.

Richard