Common mistakes in setting up DNS on a network

When administrators set up DNS on a network that has a single Windows 2000 domain controller what are the common mistakes that these administrators usually do?

When administrators set up DNS on a network that has a single Windows 2000 domain controller what are the common mistakes that these administrators usually do?
All of administrators do one most common mistake that when they configure DNSÂ to print the DC/ DNS servers to IPs DNS servers as their primary server.
The misconception behind this error is to connect the DC/ DNS servers to the Internet and therefore the ISP DNS IP addresses are being added to DC/ DNS servers and of course they do not understand basic DNS concept.
This is the most common mistake / error done by Network Administrator because they configure DNS they must understand the actual means of each and every option briefly so that it will make misconception clear and it will not lead to mistakes.