[Asterisk-Users] Asterisk behind LinkSys NAT Routing

[Robert L Mathews]

At 11/3/03 10:00 AM, Martin Pycko <martinp at digium.com> wrote:

>> Is "externip" and new parameter??
>
>It's new. It prevents asterisk from putting the private IP in the messages
>that asterisk sends with SIP.

Does it take an IP address, like "externip=1.2.3.4"? And does it then 
force the SIP messages for that channel to use the "externip" value 
instead of the server's local IP address?

If so, that's useful; it will help people who know in advance that a 
certain phone is on one side of a NAT or the other.

However, it would be nicer still if it could "fix" the SIP messages only 
when necessary, using a subnet mask or STUN, as has been proposed.

The reason is that hard-coding an IP address to use when communicating 
with a certain client means you can't have a phone in an office (on the 
same side of the NAT as Asterisk) during the day, then take the phone 
home at night (on the other side of the NAT) and have it work without 
changing sip.conf.

-- 
Robert L Mathews, Tiger Technologies      http://www.tigertech.net/