Answer
Active Directory is the directory service for Windows 2000. Active Directory stores all of the objects that make up a Windows 2000 network, such as user objects, group objects, and computer objects. Active Directory provides the services that enable users to locate objects on the network and also provides administrators with the tools that are necessary to manage a Windows 2000 network.
Answer
A site is a combination of one or more IP subnets that are connected by a high-speed link. A domain is a logical grouping of servers and other network resources under a single domain name. A site is a component of the Active Directory physical structure, and a domain is a component of the logical structure.
Answer
A tree is a group of one of more domains, all of which share a contiguous DNS namespace. A forest is a collection of two or more trees that form a noncontiguous DNS namespace. In both trees and forests, all domains share transitive trusts, a common schema, and a common global catalog.
Answer
DNS provides name resolution, the ability to map computer names to the corresponding IP address, and namespace definition. Active Directory domains use DNS naming conventions and a locator service. DNS allows clients to locate servers that provide necessary services, such as the global catalog and authentication.