I'm working on a migration NT4 Server Domain Controller to 2003 Active Directory DC, first step is to install a Secondary DC running Windows Server 2003 on a brand new computer.

I joined this machine to the domain, logged in with an account who is an Domain Administrator, and now I'm trying to dcpromo as a Secondary DC.

On the next screen I'm asking to put informations (username, password and domain) I get an error saying something like "No Active Directory DC named domdom.lan (my test domain) can be reached".

I successfully created a NT4 BDC, I can add rights to other users and navigate/search into them, I can tracert and ping the PDC without any troubles... I don't understand why it doesn't work, so please help me. :)


  • Hmmm you don't seem to agree each others. Can I keep the same domain name to make the migration transparent to the users and other application servers or not ? I tried before, as you say, to upgrade NT4 to 2003 but on startup dcpromo wants me to create a new domain, that's not what I want... – Ponpon Aug 31 '10 at 21:16
  • See Flip's comment. – Yuhong Bao Dec 29 '12 at 4:16

This isn't how you upgrade an NT4 domain to active directory. You have 2 options:

  1. Create a new Active Directory domain and migrate all computers and users into the new domain
  2. Upgrade the NT4 server to run Server 2003. During the upgrade process, it will convert the domain to Active Directory. Obviously, make sure you have a good backup first.

Here's Microsoft's white paper on the process. I'd consider it required reading.


  • I tried your 2nd solution first, but after reboot, dcpromo doesn't keep my domain name but wants to create a new one, I have to keep my domain in place... or maybe I missed something? – user52936 Aug 31 '10 at 13:35
  • @Ponpon, You don't really want to keep the single label domain name; it will cause a lot of problem in the future. Please read up on planning an Active Directory install and carefully plan before pulling the trigger. – Chris S Aug 31 '10 at 13:38
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    I'm not so sure I can give any more help than I already have. It's been a very long time since I've messed with NT4. I'd throw it up in my lab, but my Technet doesn't give me access to it. If this is that critical, you should probably hire a consultant. Extra money, but well worth it to have somebody who has done a kabajillion of these and knows where the monsters are hiding. – Jason Berg Aug 31 '10 at 15:48
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    @Ponpon, you're playing with fire doing a shotgun upgrade like this with a thousand clients that can't be reconfigured and no room for downtime. You'd be much better off doing a long duration staged migration where you do the migration over the course of a year (or whatever time frame works best), making changes at opportune times and sharply limiting the potential for outages. As Jason said, hire a consultant who knows this stuff if you don't. – Chris S Sep 1 '10 at 0:14
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    See Flip's comment. You don't need to reconfigure the client computers. – Yuhong Bao Dec 29 '12 at 3:27

There's no way to add a 2003 domain controller to a NT4 domain; your only option is to perform an in-place upgrade of a NT4 PDC: this will convert the domain to Active Directory, and then you will be able to add new 2003 DCs.

Converting the domain will require you to setup a proper DNS infrastructure, which is critical to AD operation; this can be automatically done during the NT -> 2003 upgrade. This will also give your domain two names instead of one: the NetBIOS name (i.e. the NT4-style domain name) will remain unchanged, but a new DNS name will be created, usually by appending some suffix to the NT4 domain name. So, if your domain is called "MYDOMAIN", you will be asked during the upgrade to supply a DNS name, which could be anything you want, provided it's not a single-label name; "mydomain.local" or "mydomain.com" are both fine choices, but usually you don't want this to be the same as your public domain name (if you have one), due to potential DNS issues.

After the upgrade is performed, you'll end up with a working Active Directory domain, but your main 2003 domain controller will be a server that has been upgraded from NT; it's usually not advised to keep it running, as it may not be completely stable and will probably not have very recent hardware. You will need to add other 2003 DCs to the domain (this time using DCPROMO), move the DNS service and the FSMO roles to them, and demote (using DCPROMO again) this server in order to properly remove it from Active Directory; you'll also need to remove NT4 BDCs, if you have them.

As you can see, the process is not overly complex, but it requires a lot of care and attention to details; also, it will require some thorough planning and testing. But it's still strongly suggested to act this way, because migrating your domain to a new one using the Active Directoy Migration Tool is a lot more complex and error-prone.

For more details, refer to the Technet articles other people have linked in their answers.


You can do it like this:

1-Install another NT4 server as BDC off the domain to be upgraded. - It will get a copy of all the accounts

2-Upgrade this (newly installed) NT4 server directly to Win2003 (I have done in the past with no problems) - You now have a Win2003 with all the accounts of the domain - Promote to PDC

3-Install another Win2003 from scratch to have a clean DC.

  • If everything went fine you can know disconnect the NT4 DC

You should try this in lab first!


  • This is exactly the approach I took a couple of years ago to move off of NT4 DC. Worked great. – Chris_K Aug 31 '10 at 17:25
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    "You now have a Win2003 with all the accounts of the domain - Promote to PDC"? Perhaps you mean to assign the PDC emulator role. Let's stop propagating the idea that there is a PDC in Active Directory. – John Gardeniers Aug 31 '10 at 21:45

I highly recommend not upgrading the NT4 Domain to Active Directory. You can use the ADMT to migrate the data from the old domain to a new AD install; eliminating the cruft leftover from the NT4 domain, and carefully planning your AD.

ADMT Guide and Tools links.

  • +1 That's far better than doing an in-place upgrade, which always leaves crap behind. – John Gardeniers Aug 31 '10 at 21:46
  • I disagree. Upgrading a domain doesn't usually leave any crap behind (as opposed to upgrading a server, which does, and should thus only be done as an intermediate step); migrating everything to a new domain can instead easily become a really bigger headache than a properly-done domain upgrade. – Massimo Dec 29 '12 at 16:59

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