[asterisk-users] SIP source address error

[Dave Platt]

> It's set to bind to 0.0.0.0, which IIRC is nothing strange.
> 
> The question remains: how can a remote Asterisk server be receiving  
> SIP packets that still contain the private net IP address of a client?

It sounds to me as if the client hasn't been told to use its
gateway's public IP address in the SIP conversation, and as if
the client isn't sending its outbound packets through a gateway/NAT
which is SIP-aware and can rewrite the SIP data accordingly.

There are several approaches which can work:

-  The gateway is properly configured to forward its external
   ports to the client, and the client is manually configured to
   use the gateway's external IP address in its SIP protocol
   exchanges.

-  The gateway does port forwarding and NAT properly, and is
   also SIP-aware - it intercepts and rewrites the contents of
   the outbound SIP packets, changing the IP address and port
   given by the client to its own IP address and whatever
   external port it has NAT'ed / redirected to the client.

-  The gateway does port forwarding and NAT properly, and the
   client is configured to use STUN to figure out what public
   IP address/port its packets are being NAT'ed to.

-  The client doesn't talk directly to the outside peers, but
   goes through a SIP proxy running on the gateway.

In your case, it sounds as if the client and gateway aren't
doing one of these things.  As a result, the client's SIP
protocol packets still contain its private-net IP and port,
at the time they reach the remote server.