[asterisk-dev] STUN support in chan_sip revisited

[Klaus Darilion]

Am 08.08.2010 21:16, schrieb 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?

Some providers reject too small Expires values. Thus Asterisk would need 
a feature to send REGISTERs with the required high Expires header, but 
reregisters much earlier although the registration has not expired.

regards
klaus


>
> (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