I have a Windows Server 2003 with a domain name of: test.testdomain.com
I want to replace this DC with a new 2012r2 but want to know if I should rename the domain first and then promote a new domain controller or promote the new 2012r2 and then perform the rename process?
With my test VMs, I am running 2012r2 and no problems at all, whole rename process went very smoothly but I am not as confident with 2003. Any advice?
Barring anything else that might prevent bringing the domain up to 2012 functional levels, I would vote to bring the domain up first and then rename the domain.
While renaming is supported on 2003 domain/forest functional levels, IMO it would be better to get the domain up to 2012 levels. But it isn't a requirement necessarily...you can do a domain rename starting with Windows 2003.
But since you already know the procedure on your test 2012R2 VMs, this is what I'm recommending above ^^.
