asterisk users - Aug 2007 - Contact: header and NAT.

Greetings,

I have a problem getting Asterisk registered as a UAC against the 
MetaSwitch call agent, because the customer insists on running it on a
NAT'd box.  Thus, the Contact: field in the REGISTER request betrays
the private IP address of the Asterisk box, but the source IP of the
message is a public one.

Most registrars don't have a problem with this, including Asterisk. 
However, MetaSwitch doesn't like that;  it expects (whether doing
IP-trust or user authentication) to contact the SIP peer at such and
such IP address in the SIP binding, and expects that's what the Contact:
reachability information will be too.

Any way to overcome this in Asterisk?  I thought about the externip= 
option but it did not seem to work from an internal test box that is
not behind NAT.

Thanks,

-- Alex

--
Alex Balashov
Evariste Systems
Web    : http://www.evaristesys.com/
Tel    : +1-678-954-0670
Direct : +1-678-954-0671

Got this figured out.  externip= does work if the other NAT-related 
options are also enabled, plus it appears that Trixbox (which is what
the end-user was using, it seems) handles this well in its config file
structure regardless.

--
Alex Balashov
Evariste Systems
Web    : http://www.evaristesys.com/
Tel    : +1-678-954-0670
Direct : +1-678-954-0671