Editing Windows 2000 (section)

==== Active Directory ====
{{main|Active Directory}}

A new way of organizing [[Windows Server domain|Windows network domains]], or groups of resources, called Active Directory, is introduced with Windows 2000 to replace Windows NT's earlier domain model. Active Directory's hierarchical nature allowed administrators a built-in way to manage user and computer policies and user accounts, and to automatically deploy programs and updates with a greater degree of scalability and centralization than provided in previous Windows versions. User information stored in Active Directory also provided a convenient phone book-like function to end users. Active Directory domains can vary from small installations with a few hundred objects, to large installations with millions. Active Directory can organise and link groups of domains into a contiguous [[domain name]] space to form ''trees''. Groups of trees outside of the same namespace can be linked together to form ''forests.''

Active Directory services could always be installed on a Windows 2000 Server Standard, Advanced, or Datacenter computer, and cannot be installed on a Windows 2000 Professional computer. However, Windows 2000 Professional is the first client operating system able to exploit Active Directory's new features. As part of an organization's migration, Windows NT clients continued to function until all clients were upgraded to Windows 2000 Professional, at which point the Active Directory domain could be switched to [[native mode]] and maximum functionality achieved.

Active Directory requires a DNS server that supports [[SRV resource record]]s, or that an organization's existing DNS infrastructure be upgraded to support this. There should be one or more [[domain controller]]s to hold the Active Directory database and provide Active Directory [[directory services]].