[Asterisk-Users] Problems with chan_sip on multi-homed hosts

[The Traveller]

Hey all,

I'm experiencing a problem with chan_sip on a multi-homed machine.
The machine has 1 interface to the rest of the world and 1 interface
on a local network.  The local network has public IP-addresses, though,
and the IP-addresses of both interfaces are reachable from the outside
world, but by default, outgoing traffic from that machine to the outside
world will have the IP-address of the interface the default-route points
to as it's source, which is the one with the outside world behind it,
obviously.

I've set the bind-address in "sip.conf" to the IP-address of the interface
on the local network, because I want to force it to only use that interface's
IP-address.  This works great for binding only to that IP-address and I can
even make outgoing calls, but when registering to a remote SIP-provider,
chan_sip seems to use the IP-address of the wrong interface (the one the
default-route points to) as the source of it's registration-requests, so
as soon as a call comes in from that SIP-provider, it's sent to that
IP-address and fails, as chan_sip isn't listening on it.
BTW: The remote SIP-provider is FWD in this case.



    Grtz,

      Oliver