Tipicall SIP- call cut off

Come across an issue with the IPCortex and Tipicall SIP where the call sets up fine but drops after about 10 seconds. From a Wireshark I think that the issue is where the internal IP address( of the IPCortex is listed in the Contact URI of the Message header ->

Contact: sip:01603964312@
Contact URI: sip:01603964312@
Contact URI User Part: 01603964312
Contact URI Host Part:
Contact URI Host Port: 5060

which the SBC then uses as the return address but can’t route to it so the call is dropped due to timeout. I have confirmed this with Tipicall.

Do you know/can you find out where this Contact URI information for the SIP packet construction is located so that we can modify to get this working ok?

There’s a setting called “Identify using external NAT address” under the SIP trunk configuration. Set this to yes to use the external address instead, which is normally configured from the global screen.

SIP trunk configuration like the following:

If, like the above it says “Global is NOT SET”, add the external IP in the global screen:

After that, the SDP should be shown to originate the correct IP.

Hope this helps!