Microsoft Knowledge Base Article 317590 contains the following summary:
This article describes how to configure the DNS dynamic update functionality in Windows 2000.
The DNS dynamic update functionality enables DNS client computers to register and dynamically update
their resource records with a DNS server whenever changes occur. If you use this functionality,
you can reduce the need for manual administration of zone records, especially for clients that frequently
move or change locations and use Dynamic Host Configuration Protocol (DHCP) to obtain an Internet Protocol (IP) address.
Windows 2000 provides client and server support to use the dynamic update functionality as described in Request for Comments (RFC) 2136. For DNS servers, the DNS service allows you to enable or disable the DNS dynamic update functionality on a per-zone basis at each server that is configured to load either a standard primary or directory-integrated zone.