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
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!