Hi All,

So an interesting one here. I’m doing pass through registrations using the dispatcher module in Kamailio and I’m using the Path Module to set the Path header In Register request so that Freeswitch knows to follow the route via Kamailio to find the sipPhone in future.

In summary:

[SIP Phone]------[NAT]------[(externalip)Kamailio(internalip)]-------[FS-Registrar]

The problem I’m having is that the Path header is being added with the external ip address of the Kamailio instance not the internal ip  e.g. “Path: sip:(externalip);transport=tcp” which mean FS doesn’t root new calls out to the SIPPhone correctly via kamailios internal ip.

I have noticed that if I remove the ;transport=tcp from the FS-Register address in my dispatcher group so that the last hop (from kamailio to FS-Register) is done over UDP then the problem corrects itself.  (although this does present new issues whilst calling out back along the path from FS, and we also have a prerequisite to use TCP so this doesn’t help).

Has anyone had any experience of this issue?  I can’t see what I’ve done wrong here.

Many Thanks

Rob