SIP registeration with provider - TCP

I am currently using a Microsoft Lync environment integrated into FreePBX. Lync requires TCP for it’s VOIP traffic yet FreePBX/Asterisk keeps registering with our provider in UDP. This is causing issues and I want to know how to force registration in TCP over port 5060.

I have set ‘transport=tcp’ on all trunks(including one for my provider). I also modified ‘Asterisk SIP Settings’ with the following values


After this I am still seeing the following in wireshark:

-Request: REGISTER
SIP/2.0/UDP XXX.XX.XX.XX:5060;branch=z9hG4bK478eed37;rport

Any ideas how to force registration with TCP?

Have you made sure Flowroute supports TCP?

Ive always used UDP with Flowroute.

Whats wrong with TCP to Lync on its trunk and UDP to Flowroute on its trunk?

How would Lync know the other end was UDP?

Works perfect. Can’t believe I missed that.


ignore my comment above, wrong thread