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Upgrading NT 4.0 BDC to Win2k Domain Controller

Please see my past posted (closed question) for background information:


In a nutshell, I have taken a new system and installed NT 4.0 server on the system as a BDC.  I upgraded it to SP6a.  I  now have a working PDC and the newly created BDC for my NT 4.0 domain.

I was wondering if I could upgrade the newly created BDC to Win2k (and make it be a domain controller), or if I had to use a PDC for the upgrade?  Can a NT 4.0 BDC be used for this, or does the system have to be a PDC?  Basically, I wanted to be able to LEAVE my current NT 4.0 domain running in place, use a seperate system to create a Win2k domain controller with all the NT 4.0 account information in place.  Then, I could simply, pull out the current NT 4.0 PDC and have a working Win2k domain controller.

Any other thoughts about this would be greatly apprecaited!


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1 Solution
You'll have to upgrade the PDC, a BDC won't do it. You can promote your new BDC to PDC, then take the old PDC (now BDC) offline as a backup.
I'd urgently suggest you move to Server 2003, though. The upgrade has been improved since 2000, and I've experienced it to run smoothly, not to mention that 2000 will be retired in the not so far future; there won't even be a Service Pack 5 anymore, only a rollup of the post-SP4 fixes.
Here are some articles that should help.
If you already have W2k/XP clients, you might have a look at this article before starting the upgrade:
How to prevent overloading on the first domain controller during domain upgrade

And you might want (if you haven't done so already) to install a DNS server on your new machine before the upgrade and make sure its DNS settings are correct (don't forget to re-run SP6 after installing the DNS service):
Frequently Asked Questions About Windows 2000 DNS and Windows Server 2003 DNS

Best practices for DNS client settings in Windows 2000 Server and in Windows Server 2003

And some other links that might be useful:
Tools and Documentation for Upgrading to Windows Server 2003

Background Information for Upgrading to Windows Server 2003 Active Directory

Migrating Windows NT Server 4.0 Domains to Windows Server 2003 Active Directory
pugdog_fanAuthor Commented:
One last thing ....

When I upgrade my new BDC to the PDC (which will make the current PDC into a BDC) ...

Can I leave that BDC up and running, so the clients can log in and use the domain ...

While I take the PDC offline and do the upgrade to Win2k?

We need to have the NT 4.0 domain running while this upgrade to Win2k is done in the background with no downtime.

Basically, that should work, too (haven't tried it this way, though). Make sure that while you disconnect the PDC, you physically attach the NIC to a hub or switch or whatever; dcpromo needs a valid IP stack.
If you have a W2k3 machine with 1GB RAM (or more), I'd recommend you create a test environment using Virtual Server (evaluation kit is available), where you can test the upgrade easily without endangering your production environment.
Microsoft Virtual Server 2005

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