[asterisk-users] Losing local SIP phones when internet goes down?

[--[ UxBoD ]--]

----- "Randy R" <randulo2008 at gmail.com> wrote:

> On Fri, Feb 5, 2010 at 8:41 AM, Olle E. Johansson <oej at edvina.net>
> wrote:
> >>> What I have seen on my asterisk box when I had a up/down adsl line
> was
> >>> that the asterisk box couldn't do dns resolution and would hang(
> well no
> >>> other internal calls could be made, seemed like some sort of
> semaphore
> >>> was stuck) when the adsl came up and dns could be done,
> everything
> >>> worked fine again
> 
> Confirmed and experienced years ago in a release far, far away.
> 
> > Yes, that is the case. Asterisk doesn't have asynchronus DNS
> support, so in order to work when the link is down, you need a local
> resolver, like a caching BIND server, on the same host. The calls to
> DNS resolvers in Asterisk is synchronus, so Asterisk will wait for the
> response to arrive.
> 
> IIRC, at the time I had this problem, asterisk did not answer analog
> phone lines either so as a company we had no phones and had to revert
> to regular telephones plugged into the wall. Even if Internet is
> working, if the configured DNS is down, you're still sunk. This
> sorely
> needs to be fixed IMO.
> 
> /r

Why not run a internal DNS with forwarders to your ISP ? That way Asterisk can still resolve itself and hosts internally.

-- 
Thanks, Phil