Hi Daniel, Thanks for the response. To answer your questions: is kamailio listening on both externalip and internalip? yes Do you have ip routes from externalip to FS ip? No You can try with mhomed=1 – Already have this enabled force_send_socket() this did fix my problem! But I find it a bit strange that we need to resort to this, could this be a bug ? I forgot to mention previously that we are using VIPs on both the external and internal interfaces, could this be related to the issue? Thanks again Rob From: sr-users-bounces(a)lists.sip-router.org [mailto:sr-users-bounces@lists.sip-router.org] On Behalf Of Daniel-Constantin Mierla Sent: 06 March 2014 11:10 To: Kamailio (SER) - Users Mailing List Subject: Re: [SR-Users] Incorrect IP address in path header Hello, is kamailio listening on both externalip and internalip? Do you have ip routes from externalip to FS ip? You can try with mhomed=1 or force the send socket with force_send_socket() or assignment to $fs. Cheers, Daniel On 05/03/14 20:11, Rob Moore wrote: 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<sip:%28externalip%29;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 _______________________________________________ SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list sr-users@lists.sip-router.org<mailto:sr-users@lists.sip-router.org> http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users -- Daniel-Constantin Mierla - http://www.asipto.com http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda