DNS is a lifeline of for internet apps. Almost all critical UNIX and Linux services depends upon working of DNS servers. Here are five things you can do to make sure your DNS is in good shape and not causing problems for the rest of the Internet, which, by the way, also includes you.
DNS Is Really, Really Important
Every time we get email, access a web page, make a VoIP call, or complete many other tasks, we use the Domain Name System (DNS). That makes DNS part of the critical infrastructure of the Internet.
This article describes five things that you can do to keep you and your organization safe as well as reduce unnecessary load on the DNS infrastructure:
a] Reverse-Map Private (RFC1918) IP Addresses in Your DNS
b] Ensure That Localhost Is Forward- and Reverse-Mapped
c] Ensure That Your Domain Name Does Not Have a Lame Delegation
d] Ensure That You Are Not Running an Open Recursive Name Server
e] Ensure That Your Email Address Is Correct in the SOA RR
For each of the items discussed, the corrective actions and BIND configuration (named.conf) or zone file fragments are included. You may also find our list of troubleshooting BIND tools useful.
=> Five Basic Mistakes Not to Make in DNS [oreillynet.com]