[SR-Users] Kamilio and AWS Route 53 latency regions

Klaus Darilion klaus.mailinglists at pernau.at
Wed Oct 16 14:41:32 CEST 2013

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
                         outboundproxy 1:
                         registrar 1:

              Internet (public IP)                  Cloud 2
                         outboundproxy 2:
                         registrar 2:

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.


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