Active Directory domains. Aka W2000 domains. Used by networks administered by a Windows 2000 Server.
- In a pure W2000 domain, computers are identified by Active Directory object, IP address. A DNS is required but WINS is not.
- In a mixed W200 domain, computers are identified by Active Directory object, IP address, and NetBIOS name. A DNS and WINS are required.
- Active Directory objects mirror the DNS hierarchy but occupy separate namespaces. Both are mapped to the flat NetBIOS namespace as necessary.
Note that the left most item of a DNS name can be a computer, but the Active Directory hierarchy tree only contains domains. Note also that TLDs are outside of the Active Directory although they appear as part of a domain name. EG: Everything after "comp" is a tree:
A forest is a collection of trees organized as peers and connected by two-way transitive trust relationships. Transitive means that if domain A trusts domain B, then domain A trusts all the domains that domain B trusts. The first tree created in the forest is the forest root domain.