Im running ubuntu 10.04 and Bind9 behind a firewall. I have forwarded Ports 53 (UDP/TCP) to the local server (192.168.0.4).
The DNS system seems to be hit-and-miss when the firewall is enabled, however when I assign the server as the default DMZ server it works fine.
I do know Bind was never designed to run behind a firewall, however I am a bit weary of running the server open to the wide world all the time (I'm not a security guru, so I'm treading cautiously!)
If anyone could shed light on the situation I'd appreciate it. The server is located at 18.104.22.168 (currently behind a firewall) if anyone wants a play around