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

[Olle E. Johansson]

5 feb 2010 kl. 06.49 skrev Anthony Messina:

> On Thursday 04 February 2010 23:22:27 Alex Samad 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
> 
> I can confirm that exact same behavior: 1.6.1.12

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.

I've applied for funding to fix this for a few years, but it hasn't really gotten the attention from anyone with resources needed. There are several libraries out there we could use. Resiprocate use the c-ares library, originally from curl. If anyone wants to add this code, contributions are always welcome.

/O