new Domain Controller with same IP

ithawaii used Ask the Experts™
I have 2 win2003 domain controllers (let's call them DC1 and DC2). Both of them are our DNS and DHCP servers. Since both of them are very old (more than 8 years old), I want to replace them with win2008 (call them DC3 and DC4). More than 50% of our workstations are using static IP with static DNS servers info. I want to keep administrative tasks to the minimum. So by the end of this project, I want DC3 and DC4 to have IP of DC1 and DC2.

Here's my plan: promote DC3 to domain controller > demote DC2 and take it offline> assign DC2's IP to DC3 > promote DC4 to domain controller > demote DC1 and take it offline > assign DC1's IP to DC4

It sounds simple but you'll never know what you get yourself into when it comes to domain controller.

couple questions:
- Is it a good plan?
- or is there a better way to handle it?
- or should I keep it simple like this: give DC3 and DC4 new IP > change DNS servers on all workstations that use static IP?
- anything I should be aware of when new domain controllers use same IP as old domain controllers?
- should I go with win2008 or win2008 R2? we have about 300 clients (workstations + servers)

Thanks in advance!!

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Top Expert 2013
Yes you can use the same IP and same name   good blog from ace here

Transfer the FSMO roles, double check that the old machine/IP are not in AD to make sure.

I'd go with 2008 R2.  (if you current DCs are 32 bit use adprep32 to prep your forest/domain)


You plan could do but why not set all the clients to DHCP. THis wil make it a lot easier to change is the future.
Top Expert 2012
Just to add

Here is a full guide

Article about adprep in Windows 2008 Server R2

Run Dcdiag to check health of the domain before promotion and demotion

Make sure you delete any DNS records for the DC before adding the new DC

Easier thing to do, is to promote DC3 and DC4 and never touch their original IP addresses. Onve you take you old DCs done (one at a time) add the old IP addresses to your new servers.
(You can jave multiple addresses assignes to the same adapter) This way you avoid any DNS problems both for your servers and clients.


Thanks for all the details. It really helps to point me to the right direction.

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