Hi Alex
Are you talking about the proxy's own Via hop?
Exactly...
If your "advertised" address is an IP rather than a DNS name, that should be mimicked in the Via headers inserted by the proxy.
Well the issue is, that we operate two kamailio proxy with DMQ synced states so that if one fails, the other will get the traffic.
But that does not work, if the Via contains the IP address of the proxy. So I added a hostname in the advertised config to have a hostname pointing to both ip addresses in the Via.
This works towards our IC SBC and towards other kamailio instances we use as registrar, but not towards one of our older 'commercial' voice switches.
So towards some 'endpoints' I would need an IP in the Via and towards others I would need a hostname.
But I realised, we most probably have to re-consider our idea to run all our kamailio instances in a load-balanced DMQ master-master set-up.
A CPE, even when the NAPTR entry or DNS Hostname it registers to points to multiple registrar instances, in the end registers to ONE ip address. In a NAT scenario, this is the IP which the SIP ALG on the customer firewall handles.
In a Master-Master registrar scenario, the INVITE towards a CPE might originate from the IP of the registrar that CPE did not register to and therefore the SIP ALG not knowing about and never make it through NAT.
PS: Still looking for ideas, how this could be solved.