Windows 2000 DNS: With Active Directory and Without Active Directory

With Windows 2000 DNS, can be utilized as a traditional DNS server. You are able to use similar configuration files and directly interface with non-Microsoft DNS servers and Windows NT 4.0 DNS servers. This use of Windows 2000 DNS provides for integration with an existing DNS implementation as either a secondary or a primary DNS server. If you bring a Windows 2000 DNS into an existing DNS environment, it is typically as a secondary server that uses the typical full-zone file transfers.

You can also integrate the DNS databases into Active Directory. If you decide to use Windows 2000 DNS and Active Directory integration, you are able to take advantage of Active Directory's replication scheme and multi-master approach. Windows 2000 DNS supports RFC1995, which enables zones to be transferred (or replicated) incrementally. In addition, if the Windows 2000 DNS zones are integrated into Active Directory, they become full participants in the multi-master database. This eliminates the single point of failure associated with the traditional DNS strategy. With traditional DNS implementations, the primary DNS server is a single point of failure. If the primary goes down, there is no server to update the secondary servers. With the Microsoft implementation and the integration with Active Directory, each server acts as a primary master.

There is a potential risk with the multi-master replication. With multiple masters, a dynamic DNS (DDNS) update to different DNS servers provides the possible risk that queries to the two different DNS servers could provide different results. This can happen if a system that is registered with DNS is moved. The machine registers with a DNS server, and until it propagates the new address, the remaining DNS servers return the wrong result for the system that is moved.