Back To Basics: DNS Server Roles -- Caching-only Servers Page 4
Dynamic DNS Servers (DDNS)
If there is one characteristic the defines the difference between the Windows 2000 DNS Server and previous versions of Microsoft DNS Servers, it is the Windows 2000 DNS Server's ability to dynamically update the information contained in its zone databases.
This behavior is very much like what you have seen with WINS Servers. A WINS Server allows NetBIOS nodes on the network to update their NetBIOS name and IP address mappings dynamically. This was a real advantage on earlier versions of Microsoft networks since all of them had been NetBIOS based.
Windows 2000 is free of the shackles of NetBIOS (for the most part) and uses the DNS scheme for computer and domain naming. While there are many advantages to using the DNS rather than NetBIOS, there is a major problem: zone database files were originally designed to be static databases. If any update needed to be done to the zone contents, it would have to be done manually by the DNS administrator.
Manual administration of the zone databases on a large a DNS based network, such as an enterprise Windows 2000 network, would be a very large and difficult task. The task would be even more onerous when DHCP is used extensively and when DHCP assigns varying IP addresses to shared network resources. The Dynamic DNS Update Protocol solves this major hurdle to widespread implementation of DNS on Windows networks.
Dynamic DNS works more effortlessly when all the clients on the network are running Windows 2000. A Windows 2000 client can register its own Host (A) record and Pointer (PTR) record information in the DDNS zone database file. Most network won't work this way, and you'll have a mix of network clients. In this case, you should take advantage of the Windows 2000 DHCP Server's ability to dynamic register Host and Pointer record information at the DDNS Server on the behalf of downlevel Windows based clients.
The Windows 2000 Server can take on many different roles. What role the server takes depends on what requirements you have for your network. DNS Server roles are also dependent on whether or not you choose to integrate DNS with the Active Directory. We haven't address Active Directory Integrated DNS Servers yet, but they are something you should become familiar with before implementing DNS on your network, and definitely before you take your Windows 2000 exams!