[Asterisk-Users] SIP Phones behind dynamic IPs

[Kevin P. Fleming]

Chris Bagnall wrote:

> I think what's happening is that the ADSL router is reconnecting after a
> break in the connection (as it should), getting a different IP, but the
> phones don't seem to be recognising they've got a different IP and updating
> the asterisk server with the good news.

'recognize'? The phone cannot know that the external IP has been
changed, unless it is using a STUN server and periodically re-doing the
STUN queries (which I doubt any phones do).

Probably the best you are going to be able to do is to set the
registration interval on the phone to something short enough to not be
too painful for your Asterisk server but still enough to keep the phone
reachable.