[OpenSER-Users] Problem with otg proxy when service provider has two registrars

[Robert Dyck]

I am experimenting with using openser as the basis for a home telephone 
system. Openser resides on the same node as my NAT. I have also employed the 
rtp proxy feature. I have had some success with my setup but recently I 
encountered a problem registering with a particular service provider.

My phones are set up to use openser as an outgoing proxy. They can register 
with various service providers except one. From tracing the messages I 
believe I know what is going wrong. The REGISTER is sent to openser which 
does a DNS lookup. This results in two registrars. Openser picks one and 
forwards the messages. The registrar issues a challenge as expected which is 
sent back to the phone. The phone sends its credentials to openser. Openser 
does another DNS lookup and sends the message to the other registrar. This 
registrar also issues a challenge. Thus it continues forever with the 
credentials being sent to the wrong registrar.

My question is, how do I get openser to send the credentials to the registrar 
that is requesting them?

Thanks in advance for any advice.