Make sure trixbox works when Internet is down

It's true that the default trixbox-ce setup can not call PSTN or another extension when internet is down. Actually it still rings the another extension if you wait 20 - 90 sec for DNS queries to timeout.

After examing caching nameserver's debuging log, I found a simple solution that make the trixbox works (such as call internal extension and PSTN) when internet is down or even without internet connection.

1. Install cache only name server on the trixbox (BIND with caching config)

yum -y install caching-nameserver
chkconfig --add named
chkconfig --level 345 named on
echo "* IN A 127.0.0.2" >> /var/named/localdomain.zone
service named start

2. Set trixbox as its own DNS server by adding 127.0.0.1 on the first line of /etc/resolve.conf, like

127.0.0.1
your.other.dns.servers

3. Make sure trixbox has default settings for file /etc/sysconfig/network

NETWOKING=yes
HOSTNAME=trixbox1.localdomain

(Do not change HOSTNAME to trixbox1.yourdomain.com )

and for file /etc/hosts, something like

127.0.0.1 trixbox1.localdomain trixbox1 localhost.localdomain localhost

4. Reboot (try without intetnet)

Please let me know if this works for you.

PS: the problem is not related to the VOIP trunk hostnames, as noted in my previous post on another thread. Can any Asterisk expert answer why asterisk is looking up the ip for 2001-a1b2c3d4.localdomain when ext. 2001 is calling? This is causing the long delay when internet is down. Above solution works around this DNS lookup bug/feature.