Migrate Active Directory 2008 to 2012 but need to keep the same ip address and server name

Question

Hi,
Current setup is 2 DCs in one site running 2008 R2 AD.
We are planning to migrate from 2008 R2 to 2012 R2 but need to keep the same ip address and server name. I have came up two plans to do this and hope someone can tell me which one would be the best approach. What is the pros
and cons in Plan A and B or may be plan C if there is a better one?
First, I was planning to do plan A but just had a second thought of Plan B.  My concern in Plan A is about changing the server name when the new 2012 R2 already running as DC.  Plan B would be changing all the old server
name and ip before they become member sever and DC. 
Any information and suggestion would be very appreciated.
Plan A
Run adprep /forestprep on 2008 R2 DC
Build a new 2012 R2 server and promote it as 3rd DCs in current Domain
Transfer FSMO from 2008 R2 to 2012 R2
Run Repadmin /syncall to force replication
Rename the demoted 2008 R2 DC to something else
Change the demoted 2008 R2 ip address to something else
Restart the demoted 2008 R2 server to take effect
Now, run Netdom computername command to change the new 2012 R2 server name to the old 2008 R2 DC server name
Change the new 2012 R2 DC's ip to old 2008 R2 DC's ip
Run ipconfig /flushdns
Run ipconfig /registerdns
DCDIAG to see any error
Plan B
Build 2 new 2012 R2 standalone servers
In 2008 R2 ServerA transfer FSMO to 2008 R2 ServerB
Demote 2008 R2 ServerA to become member server
Rename 2008 R2 ServerA to something else and change the ip address to something else and shut it down
Now, rename one of the new 2012 R2 standalone server to the old demoted 2008 R2 ServerA name
Change the new 2012 R2 standalone server ip to the old demoted 2008 R2 ServerA's ip address
Add the new 2012 R2 standalone server (now with the old 2008 R2 ServerA name and ip) to become member server
Run adprep /forestprep on the 2008 R2 ServerB
Promote the new 2012 R2 (now with the old 2008 R2 ServerA name and ip) as DC
Transfer 2008 R2 ServerB FSMO to the new 2012 R2 DC (now with the old 2008 R2 ServerA name and ip)
Demote 2008 R2 ServerB as member server
Rename 2008 R2 ServerB to something else and change the ip address to something else and shut it down
Now, rename the 2nd new 2012 R2 standalone server to the old demoted 2008 R2 ServerB name
Change the new 2012 R2 standalone server ip to the old demoted 2008 R2 SeverB 's ip address
Add the 2nd new 2012 R2 standalone server to become member server
Promote it as DC
Run DCDIAG to check error
Thanks.

Answer 1

Hi,
Renaming a Domain Controller is a risky operation which may lead to issues, therefore, I would suggest you go with the Plan B, rename the server before it becomes DC.
Here is a blog below which could be helpful to you:
Remove an Old DC and Introduce a New DC with the Same Name and IP Address
http://blogs.msmvps.com/acefekay/2010/10/09/remove-an-old-dc-and-introduce-a-new-dc-with-the-same-name-and-ip-address/
Best Regards,
Amy
Please remember to mark the replies as answers if they help and un-mark them if they provide no help. If you have feedback for TechNet Subscriber Support, contact
[email protected]