Dynamic DNS and AD in Windows 2000
Windows 2000 runs on TCP/IP, and to utilize AD, you must forsake the older Windows Internet Naming Service (WINS) technology in favor of DNS. WINS can still be useful on Windows 2000 networks, especially if you have non-Windows 2000 or XP clients. However, Active Directory will not use WINS for name resolution.The biggest downside to DNS has been that although distributed, it was still designed as a system that requires manual updates. Whenever a new host is added to a domain, an administrator needs to manually update the zone database on the primary DNS server to reference the new host. If there are secondary name servers on the network, the changes are replicated in a zone transfer.
However, a dynamic updating feature proposed in RFC 2136 provides the means for updating a zone's primary server automatically. Windows 2000 supports this new dynamic DNS, or simply DDNS. The caveat is that it works only with Windows 2000 clients, and older Windows NT, Windows 9X, and non-Windows clients still require manual updates, or at minimum, a Windows 2000 Dynamic Host Configuration Protocol (DHCP) proxy to act on their behalf during the dynamic registration process. When DDNS is enabled and Windows 2000 boots up and contacts a DHCP proxy for IP addressing information, it automatically sends an update to the name server it has been configured to use, adding its Address (A) resource record. This greatly simplifies the administration of DNS on a Windows 2000 network. In addition, DDNS simplifies the administration of AD by allowing domain controllers (DCs) to automatically register their Service (SRV) resource records into DNS without administrator intervention. It is important to note that, by default, DHCP will not automatically update DNS; you have to configure DHCP explicitly to update DNS by editing its properties and checking the box labeled Enable Updates for Clients That Do Not Support Dynamic Updates.
WINS is a proprietary Microsoft name-resolution scheme for resolving NetBIOS names to IP addresses on Microsoft networks. It's a dynamic database that allows clients to register themselves automatically and, as with DNS, is a replacement for an older, manually updated system. On Microsoft networks, LMHOSTS was the equivalent of the HOSTS files used on the Internet.
Throughout this chapter, we discuss many of the terms used in this section, including zones, zone transfers, and resource records. Also, before installing DNS, you'll need to take into account some planning considerations. We'll examine those next.