On Mon, Feb 01, 2016 at 09:17:41AM +0100, Federico Cabiddu wrote:
a solution in this case could be making usage of Path header ( https://tools.ietf.org/html/rfc3327). You have to load the path module http://www.kamailio.org/docs/modules/devel/modules/path.html and enabled its usage in registrar module
Be warned that any stateful firewall or NATed client will not accept the messages from any other sipserver to that client. My solution was to use edge/loadbalancer proxies which add the Path header using add_path_received to store both the edge/loadbalancer ip and client source before passing the request to the backends (using dispatcher).
Any backend will send messages based on the Path headers to the edge/loadbalancer and that will pass it to the client to appease statefull firewalls.