Hi, I am new to openser and trying to use it as a proxy i.e. I have a phone behind NAT, and another SIP server with all our account/registrar/routing details, I want to try mediaproxy as a far-end nat traversal solution to allow us to install phones without doing much (or anything) to the NAT firewalls.... The idea is that I set up phones to use Openser as Outbound proxy, and use symmetric RTP, and tell openser to nathelper to do regular keep alive pings. Then the phone should open SIP port to openser when registering, and OpenSER forwards the registration to the current sip server. Later invites from the current server should go back through Openser to the phone over the still open ip:port pair. MediaProxy on the openser should handle the RTP traffic between phone and old sip server.
I have got ser and mediaproxy running and outgoing calls are fine. The problem is that incoming calls are not going through the proxy... the phone registers via the openser proxy, but when initiating an incoming call to the phone the registrar server sends the SIP invite straight to the NAT firewall, which rejects it...
What do I need to do so that openSER tells the registrar to route SIP INVITES back through the openser server?
I realise that at present I am looking at a very insecure open relay - I'll add more auth and domain checking when I get the basic outbound relay / media proxy bit working.
PHONE ---- NAT ---- SER ----- SIP registrar Server with user details etc.
Thanks.