Windows 2000 Server (all editions) and Windows Server 2003 support Dynamic DNS. The benefit of Dynamic DNS is that it’s not necessary to manually update client resource records in DNS. A Windows 2000/2003 server running DHCP can also update legacy client’s resource records in DNS. If your network includes clients older than Windows 2000, this feature can save you much time.
By default this should be turned on, but you can check by right-clicking on an appropriate DHCP server or its scope and choosing Properties. Under the DNS tab, ensure that the box labeled, “Enable updates for DNS clients that do not support dynamic updates” is checked. It’s similar in Windows Server 2003, except the check box is labeled, “Dynamically update DNS A and PTR records for DHCP clients that do not request for updates (for example, clients that are running Windows NT 4.0).”