I understand a bit about the IP routing issues, I have already seen some of them with Kamailio being confused about a private vs. a published public address.

Thanks for your help, I have more ideas I am going to try today. 


On Wed, Oct 16, 2013 at 8:41 AM, Klaus Darilion <klaus.mailinglists@pernau.at> wrote:
Hi Coy!


On 16.10.2013 14:29, Coy Cardwell wrote:
Thanks.

By "as long as IP connectivity between the outbound proxies and
registrars is not filtered", what exactly must not be filtered?
The proxies and their 'local' registrars will be in the same private IP
cloud.
Then it should be fine.


Are you implying if a proxy tries to reach a nat-ed registrar in
another, different, private IP cloud it won't work?

Probably it depends on the NAT and how the cloud is connected to the Internet and other clouds. But also NATed servers should be fine, if the NAT does not mangle SIP packets and the proxies are configured to announce the public IP address.

Thus, hmm, there may be problems depending on your setup. For example:

             Internet (public IP)                  Cloud 1
              1.1.1.2                    outboundproxy 1: 10.0.1.2
              1.1.1.3                    registrar 1:     10.0.1.3

             Internet (public IP)                  Cloud 2
              2.2.2.2                    outboundproxy 2: 10.0.2.2
              2.2.2.3                    registrar 2:     10.0.2.3


If the outboundproxy (OBP) 1 talks to registrar 1, does it us the internal IP addresses or the public IP addresses? For later, Kamailio can be simply configured to announce the public IP addresses in all SIP messages. But if internal traffic uses internal IP addresses, then the OBP is "virtual" multihomed, and Kamailio must be correctly configured to announce the private IP address when talking to the registrar, but using the public IP address when talking to customer in the Internet.

Further, if OBP1 talks to registrar2, then such "virtual" mutlihomed setups are also needed on the registrar server.

Conclusion: I guess every private cloud has different network techniques how traffic is routed externally and internally. Thus, the Kamailio configuration heavily depends on the underlying network (as IP addresses are put into the SIP messages). But at least Kamailio is very flexible and up to now I always have solved strange network setups.

regards
Klaus