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I have two AD servers: and One is a Windows Server 2008 (non-R2) and the other is R2. Both are AD servers for our local network. It's a simple network, 30 clients.

Now I need to replace the hardware of these two servers for newer, most powerful ones. But the server NAMES and IP ADDRESSES must be the same after the replacement.

What should be the best path to follow and to keep the AD database?

(I cannot change the IP address when the machine is an AD server)


I'm thinking in:

  • Demote
  • Remove it from domain.
  • Add the new server into domain with the same IP
  • Promote it.
  • Do everything again for the first server

I think this will work but I'm not sure is the best way. Any tips or better ideas?

Update 2

  • How to know when everything is correctly replicated between AD servers? And how to "force" this replication to occur?
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See comment by Steven below. – murisonc Sep 15 '11 at 2:57

Yes, in your update you have it correct. Demote one and replace it using the same name and IP. Some things to watch for. When you demote make sure it gets removed from sites and services, DNS, and AD. Also make sure 1.1 has all the FSMO roles before/after removing 1.2. Add the new DC and repeat.

One more thing. I would suggest that after you add one of the new servers and get it joined, you let it rot for a day or two just to make sure everything replicates properly. I've found that when making changes to a DC it's a good idea to leave it alone for a while to get acclimated. Sounds goofy but it works.

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Thanks, man! However I will need to replace both them in a weekend, probably in one day (Sat or Sun). If memory serves me, once I did see a command to "force" replication between AD servers (to avoid the wait you mentioned). I'll look for it. – Max Sep 15 '11 at 2:13
You'll want sonar to watch replication:… In the "sites and services" snap in, you can force replication – Steven Sep 15 '11 at 2:36
@Max If you're installing a new DC, one of the options during an advanced install is to replicate all data before finishing the promotion. That should be all that you need to do to ensure that replication is complete on the new DC. – MDMarra Sep 15 '11 at 13:26

First note - As a technical matter, you can change IP addresses of AD servers. We are doing do during our current hardware migration. Perhaps you have some other reason not to do so.

Second note: running through this whole process in a weekend without prior experience is risky.

Third note: Pay particular attention to DNS. Nearly all AD issues are DNS issues. More later.

I would follow this plan

  • build & promote new server (A)
  • Build & promote second server (B)
  • allow replication (will happen quicly on a LAN given the size of your AD)
  • move FSMO roles from old server to one of the new servers
  • re-IP old server (C)
  • Re-IP server A with (C) address
  • Re-IP old server (D)
  • Re-IP server (B) with old server (D) address
  • leave old servers in place for a week, then demote

DNS: When you move it, ensure the DHCP settings for clients are updated to point to current DNS. Also ensure the domain controllers are always pointing the right DNS through each step. The BEST plan I can think of would be to move DNS off the DC for the period of the migration to that you don't have to change settings.

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