Adding first Windows Server 2012 Domain Controller within Windows 2003/2008/2008R2 network


To be able to configure Windows Server 2012 Domain Controller within Windows 2003/2008/2008R2 network we need to check if Forest Functional Level is set up at least in Windows 2003 mode. This is the lowest required Forest Functional Level allowing Windows Server 2012 Domain Controller installation. That means, Windows 2000 DCs are not supported anymore. Microsoft does not support them with cooperation with 2012 Domain Controllers. It’s time to forget about these old DCs.

Windows Server 2012 DC Forest Functional Level requirements

Windows Server 2012 DC Forest Functional Level requirements

We can check this in domain, where we want to install first 2012 DC. To verify that, we need to use “Active Directory Users and Computers” or “Active Directory Domains and Trusts” console.

Using “Active Directory Users and Computers” console, select your domain and click right mouse button (RMB) on it. Choose “Raise Domain Functional Level” and check that.

If you see screen like this (Windows 2003 mode), it means that you do not need to raise your Domain Functional Level. In other case you have to remove all Windows 2000 Domain Controllers or if you have no any, raise DFL to Windows 2003 mode or higher

Current Domain Functional Level

But remember, raising Domain Functional Level is one time action and cannot be reverted. Before you raise it to 2003 mode, please ensure that all of your Domain Controllers are running at least on Windows Server 2003. In this case all of them are running at least 2003 DCs as DFL is set up to 2003 mode, which would not be possible when any of 2000 DCs are still available.

Windows 2003 mode do not support DCs based on earlier Microsoft Windows systems like NT4 and Windows 2000

Another way for that is using Active Directory Domains and Trusts console. Run this console, select domain for which you want to check Domain Functional Level and choose “Raise Domain Functional Level”

Current Domain Functional Level

Follow the same steps as in previous console.

More about Raising Domain Functional Level you can find in another article on my blog.

In this place, you can also raise your Forest Functional Level if all of your Domain Controllers in entire forest are running on Windows Server 2003. If not, please skip below steps and go to Single Master Operation Roles section.

To raise Forest Functional Level, select “Active Directory Domains and Trusts” node, click on it RMB and choose “Raise Forest Functional Level”. On the list accept “Windows Server 2003” mode by clicking on “Raise” button.

In this case FFL is set up on Windows Server 2003 mode and there is no need to raise it.

Raising Forest Functional Level

For more information about Raising Forest Functional Level please check another article on my blog.

You can also try to determine DFL and FFL levels following artilce on my blog titled: Determine DFL and FFL using PowerShell

Now, it’s time to determine which Domain Controller(s) hold(s) Single Master Operation Roles. The most important for preparing environment for 2012 DC are

  • Schema Master
  • Infrastructure Master

We need to be sure that connection to this/these DC(s) are available during set up process. In previous versions we need to prepare environment using adprep command to extend schema and configure Infrastructure Master. From Windows Server 2012 we don’t have to run adprep first. Of course, if you wish, you can still do that but it is not mandatory step. From, now, Windows Server 2012 will do that for you if it will detect that adprep was not used before for Schema and Infrastructure preparation. That’s the newest feature in Windows Server 2012 which simplifies promotion process as much as it can. You need to only check if connection to DC(s) with mentioned operators master roles is available (it is based on similar solution applied in Exchange 2010 where you do not have to use to extend Schema yourself).

To verify necessary Operation Masters, we can use netdom command installed from Support Tools on Windows Server 2003 (in 2008/2008R2 it is available by default). Open command-line and go to default installation directory:

C:\Program Files\Support Tools and type:

netdom query fsmo

and identify DC(s) from an output

Operation Master (FSMO) roles

We collected almost all necessary information to start AD preparation for the first Windows Server 2008 R2 Domain Controller. The last and the most important part before we start preparation, is checking Forest/Domain condition by running:

  • Dcdiag (from Support Tools)
  • Repadmin (also from Support Tools)

Run in command-line on a DC where you have installed Support Tools

dcdiag /e /c /v

and check if there are no errors. If so, please correct them (in case that your forest/domain has a lot of Domain Controllers, please skip /e switch)

now run in command-line:

repadmin /showrepl /all /verbose

to check if your DCs are replicating data without errors.

For more about Active Directory Troubleshooting Tools check one of my articles on this blog


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