Upgrade to a Regional Domain in an Existing Forest
Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2
To complete the process for upgrading to a regional domain in an existing forest, perform the following tasks:
Back up all domain data.
Enable the Windows Server 2003 interim forest functional level in the existing forest.
Delegate the DNS zone in the forest root domain.
Configure protection against domain controller overload.
Upgrade the operating system of the Windows NT 4.0 PDC.
Install Active Directory.
Perform post-upgrade tests.