asterisk users - Aug 2012 - sip trunk failing to register causes sip phones to become unreachable

Hi,

I have only seen this problem when using sipgate SIP trunks which actually
"register". If the ADSL connection goes down that the sip trunk uses,
the sip phones registered locally become unreachable. This happens on any 1.6.x
or 1.8 version of asterisk I've tried. Is there a work around that
doesn't involve putting an opensips server between the asterisk server and
the sip trunk?

Thanks.

Regards,
John

On Aug 23, 2012, at 10:30 AM, John Cahill <john at dmcip.com>
wrote:
> I have only seen this problem when using sipgate SIP trunks which actually
"register". If the ADSL connection goes down that the sip trunk uses,
the sip phones registered locally become unreachable. This happens on any 1.6.x
or 1.8 version of asterisk I've tried. Is there a work around that
doesn't involve putting an opensips server between the asterisk server and
the sip trunk?
This is a common issue that I've seen many times.  The problem has to do
with DNS cache look-ups and timeouts.  What typically solves it for me is to
install a local cacheing-only DNS server on the asterisk box and point the
resolvers on the asterisk box to itself.  This will only solve the issue of an
internet outage causing the sip phones to stop working, and only for as long as
the local cache stays relevant.  If there is a power outage that takes out both
the asterisk server and the internet, and your asterisk box comes up but your
internet doesn't, this won't work.


--
Thanks,
Warren Selby, dCAP