Concise Guide to DNS and BIND, The

Firewall Rules and DNS

At least two kinds of firewalls are available. The simplest is packet filtering firewalls, and at the more advanced end of the spectrum is firewalls such as FireWall-1, which maintains complete connection state engines capable of filtering traffic in a much more intelligent manner. A commercial, GUI-equipped firewall should be quite easy to set to allow DNS traffic to pass correctly. However, please check the documentation because it might have specific, not-so-obvious recommendations about DNS configuration that you should adhere to.

In the old days, when BIND 4 ruled the networks, setting up firewall rules for DNS was quite simple. Everything—TCP and UDP, information coming from port 53, information addressed to port ...