• Stored in %SystemRoot%\Ntds\NTDS.DIT
• It is divided into several partitions: schema, configuration, global catalog, and the domain naming context (contains users, groups, computers, etc.

• Perform AD DS role.
• Run Kerberos Key Distribution Center (KDC) service, which performs authentication.

• Collection of Domains.
• First domain in a forest is the forest root domain.
•  No data is replicated outside the forest.

• The DNS namespace of domains in a forest creates trees with the forest.
• If a domain is a subdomain of another domain, the two domains are considered a tree.

• Domain Functional Levels
•          Windows 2000 native
•          Windows Server 2003
•          Windows Server 2008

     Forest Functional Levels

                 Microsoft Windows Server 2003

                 Microsoft Windows Server 2008