Before you can introduce Windows Server 2003 domain controllers, you must prepare the forest and domains with the ADPrep utility.

• ADPrep /forestprep on the schema master in your Windows 2000 forest.
• ADPrep /domainprep on the Infrastructure Master in each AD domain.

ADPrep is located in the i386 directory of the Windows Server 2003 install media.

Note: In Windows Server 2003 R2, ADPrep is not located in the same folder as in the older Windows Server 2003 media, and instead you need to look for it in the second CD. You see, Windows Server 2003 R2 comes on two installation disks. Installation disk 1 contains a slip-streamed version of Windows Server 2003 with Service Pack 2 (SP2). Installation disk 2 contains the Windows Server 2003 R2 files.

The correct version of the ADPrep.exe tool for Windows Server 2003 R2 is 5.2.3790.2075.

You can find the R2 ADPrep tool in the following folder on the second CD:

drive:\CMPNENTS\R2\ADPREP\

(where drive is the drive letter of your CD-Rom drive)

Read more about ADPrep and Windows Server 2003 R2 in KB 917385

Microsoft recommends that you have at least Service Pack (SP) 2 installed on your domain controllers before running ADPrep. SP2 fixed a critical internal AD bug, which can manifest itself when extending the schema. There were also some fixes to improve the replication delay that can be seen when indexing attributes.

The ADPrep /forestprep command extends the schema with quite a few new classes and attributes. These new schema objects are necessary for the new features supported by Windows Server 2003.

Since the schema is extended and objects are added in several places in the Configuration NC, the user running /forestprep must be a member of both the Schema Admins and Enterprise Admins groups.

The ADPrep /domainprep creates new containers and objects, modifies ACLs on some objects, and changes the meaning of the Everyone security principal.

In order to identify the current version of the schema on your active directory, please review this technote

Schema Version ObjectVersion values and corresponding operating system support level

• 13=Microsoft Windows 2000 
• 30=Original release version of Microsoft Windows Server 2003 and Microsoft Windows Server 2003 Service Pack 1 (SP1)  
• 31=Microsoft Windows Server 2003 R2