I have tested it out here since I have a similar set-up and it appears
that all you need is port 53 UDP open.

Also make sure that you have your external adapter specified in the
named.conf file. This is what screwed me up since, like you, I am using
this host for internal DNS and was specifically directing the server to
listen only on the internal adapter.

options {
listen-on { 12.218.5.147; 127.0.0.1; 192.168.0.1; };
}

hope that helps
>
> I have been trying to set up a DNS server behind a firewall and I have
> had less than desirable results.
>
> I can successfully operate a Web server behind the firewall, by opening
> TCP port 80, but the DNS server does not work even when opening port 53
> UPD and TCP.  I have restarted named and reloaded the configuration
> after placing the DNS server behind the firewall.
> My domains do not resolve from other networks (ISP's) when I put the DNS
> server behind the firewall.
> I also use this DNS server as the primary for my local network.
>
> Is there a change that needs to be made to the named config files?
> Another port that needs to be opened?
>
>
> Thanks In Advance
>
>
>
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