[asterisk-users] ISP down internal phones become unavailable

[Lacy Moore]

On Mon, Jun 21, 2010 at 7:32 AM, Ryan Wagoner <rswagoner at gmail.com> wrote:
> I saw the following lines in the log this morning. From my router logs
> I see that the connection went down as my ISP was doing maintenance
> for a few minutes last night. I can understand the external
> registrations timing out, but why do the phones become unreachable.
> They are on the internal lan within the same subnet as the Asterisk
> server. Internal DHCP and DNS was functional. If I had a PRI card in
> this system as well that would mean I couldn't make phone calls
> because the Internet is down.
>

I have a PRI, and when the Internet connection goes out so do my
phones.  I suspect it is some type of DNS issue.  I do have a SIP
trunk, and it appears that if I lose DNS to the SIP trunk, the entire
PBX is offline.  I have no actual proof of any of this, and have not
done any extensive testing to prove or disprove this.