Deploying AD DS in a Windows Server 2003 Organization
Applies To: Windows Server 2008, Windows Server 2008 R2, Windows Server 2012
If your organization is currently running Windows Server 2003 Active Directory, you can deploy Windows Server 2008 Active Directory Domain Services (AD DS) by either performing an in-place upgrade of some or all of your domain controllers' operating systems to Windows Server 2008 or by introducing domain controllers running Windows Server 2008 into your environment.
Before you can add a domain controller running Windows Server 2008 to an existing Windows Server 2003 Active Directory domain, you must run adprep, a command-line tool. Adprep extends the AD DS schema, updates default security descriptors of selected objects, and adds new directory objects as required by some applications. Adprep is available on the Windows Server 2008 installation disk (\sources\adprep\adprep.exe). For more information, see Adprep (http://go.microsoft.com/fwlink/?LinkId=99215).
The following illustration shows the steps for deploying Windows Server 2008 AD DS in a network environment that is currently running Windows Server 2003 Active Directory.
If you want to set the domain or forest functional level to Windows Server 2008, all domain controllers in your environment must run the Windows Server 2008 operating system.
Consolidating resource domains and account domains that are upgraded in place from a Windows Server 2003 environment as part of your Windows Server 2008 AD DS deployment may require interforest or intraforest domain restructuring. Restructuring AD DS domains between forests helps you reduce the complexity of the representation of your organization in AD DS, and it helps reduce the associated administrative costs. Restructuring AD DS domains within a forest helps you decrease the administrative overhead for your organization by reducing replication traffic, reducing the amount of user and group administration that is required, and simplifying the administration of Group Policy. For more information, see ADMT v3.1 Migration Guide (http://go.microsoft.com/fwlink/?LinkId=93678).
For a list of detailed tasks that you can use to plan and deploy AD DS in an organization that is running Windows Server 2003 Active Directory, see Checklist: Deploying AD DS in a Windows Server 2003 Organization.