[Asterisk-Users] how to add stun functionality in asterisk

[Olle E Johansson]

21 feb 2006 kl. 21.47 skrev Rich Adamson:

> Stun's primary role in life is to operate as an internet accessible
> application to determine the outside IP address of your firewall or
> nat box. Its usually called (by a sip phone as one example) at  
> startup,
> and the stun server returns the real outside IP address.

Right. And to add to this excellent explanation:

STUN is a discovery protocol. It does not change anything in your  
network.
It discovers properties about a NAT between the device and the STUN  
server and
thus helps the phone to automatically configure communication  
parameters that assists NAT traversal.

Outside IP address is one of them, but even more important is the  
functionality
of the NAT - how it can handle SIP signalling from one endpoint (sip  
proxy) and audio from a completely different and unknown endpoint  
(the phone).

/O