Firewall settings in Red Hat locking out remote DNS servers
I'm sure that this question is elementary for most here. I'm running a mail server on RH9.0 and i have the firewall settings set to high but within WebMin I have both pop and smtp ports opened. I noticed by using the high settings within the security app in RH9 it auto sets my DNS servers to UDP 0/0 post 55. I change it to TCP the local public IP of the server but still no go. I can't contact my ISP's DNS servers, which in turn is causing problems with email.
Due to my lack of knowledge, it's probably something stupid I've done wrong.