Change domain controller OS from 2008R2 to 2008 but keep the same host names.

Hello,

Currently we have four domain controllers running Windows 2008 R2, spread across two AD sites.

We have two Domain controllers in each AD site.

We need to change all our domain controllers from Windows 2008 R2 to Windows 2008. In short, this is required because a trust relationship needs to be temporarily setup with an old NT4 domain, and this is not possible if our domain controllers are Windows 2008 R2.

We don’t want to change the name of any of these domain controllers.

Here’s a really brief summary of what I plan to do.

1. In site1, on DC1, transfer the FISMO roles to DC2.
2. Disable inbound and outbound replication on DC1.
3. Demote DC1
4. Rebuild DC1 with new OS, add back into the domain and promote back as a DC .
5. Transfer FISMO roles back to DC1

I will repeat steps 2-4 with the other domain controllers in site2.

Although I’ve provided a really basic run down of events, is there anything crucial I may have missed here, and what else do I need be particularly mindful of?

Many thanks,