[asterisk-dev] STUN support in chan_sip revisited

[Simon Perreault]

On 08/06/2010 06:23 PM, David Vossel wrote:
> What you do you all think about using STUN as a way to simply detect
> when a network's external IP address has changed?  There is a common
> problem people have who are using Asterisk behind a NAT with an
> external dynamic IP address.  Anytime the external IP changes, all
> the external SIP devices the Asterisk box has registered to will be
> sending calls to the wrong address until the SIP registration is
> renewed.  In the past people have had to respond to this problem by
> forcing Asterisk to restart in order to renew all their SIP
> registrations.  Since there are freely available STUN servers  all
> over the place it seems like giving Asterisk the ability to use a
> STUN server as a way to detect a network address change would be a
> great idea.  By doing this, any channel drivers that register with
> external devices can be made aware of the IP change and automatically
> renew their registrations.

Two questions:

- How do you deal with NATs that have a pool of public addresses?

- What's the problem with using a small expiry parameter value in the
register line?

(Of course, a complete solution would be RFC 5626. I'm assuming we're
looking for an intermediate step that would be easy to implement.)

Simon
-- 
NAT64/DNS64 open-source --> http://ecdysis.viagenie.ca
STUN/TURN server        --> http://numb.viagenie.ca
vCard 4.0               --> http://www.vcarddav.org