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

[Olle E. Johansson]

5 feb 2010 kl. 09.28 skrev --[ 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.
> 
See above:
>> you need a local
>> resolver, like a caching BIND server, on the same host. 

/O :-)