[asterisk-users] Why asterisk down when inet server down?

[Gordon Henderson]

On Fri, 18 Jun 2010, sean darcy wrote:

> We have a 10.10.0.0 internal network. The asterisk server - 10.10.10.180
> - has a PRI connection to a T-1. Another server is the router to the
> internet. All phones in the office and the workstations are on the network.
>
> Most of the internal phones are aastra 9133i's. Here the network config
> from a phone:
>
> Network Settings
>
>    Basic Network Settings
>    DHCP                         [ ] Enabled
>    IP Address                   10.10.10.44_________
>    Subnet Mask                  255.255.255.0_______
>    Gateway                      10.10.10.180________
>    Primary DNS                  10.10.10.180________
>    Secondary DNS                0.0.0.0_____________
>
> If the network server is down, the phones go out of service. From a
> workstation I can still ssh into the asterisk server. But for some
> reason the phones don't work. I can console dial out from the server.
> The asterisk server doesn't need the internet for connectivity.
>
> Why do the internal phones go down?

If you mean that the phones simply can't dial and don't actually 
un-register themselves, it probably because asterisk needs a working DNS 
server somewhere, and with no Internet, then your DNS server - which looks 
like your gateway - which I'm guessing is just a dumb forwarder - is 
failling.

I've never undersood quite why asterisk wants to do a DNS lookup for every 
call, but not been bothered enough to do something about it other than to 
run a cacheing DNS server on the asterisk box itself just for it's own 
use.

Gordon