@dave247 said in question about setting up a new domain controller:
Hi guys I have kind of a noob question..
I have two 2008 R2 domain controllers: DC1 and DC2 (one physical one virtual), and an on-prem Exchange 2010 (SP3) server in my environment. I think I've learned enough now where I'm comfortable setting up a new domain controller and replacing an old one but I still technically haven't done it yet.
I would like to set up a 2012 R2 domain controller to replace the physical 2008 R2 domain controller, DC1. DC1 is the primary DNS server that everything in the environment looks to, and so I want to make sure everything gets replaced with the new IP address.
Note: I am going 2012 R2 DC right now because it's the highest I can go with having Exchange 2010 SP3 running. I will eventually be going to Exchange 2016 and then at that point I can make a 2016 DC.
The main thing I'm wondering about is if I can simply set up the new 2012 R2 server, promote it to domain controller, and then one by one point my servers and all the other statically mapped systems to it, without experiencing any disruptions. And right now DHCP is being controlled by the physical DC but of course that would be trivial to replace once I get the new 2012 R2 DC up and running. I really just want to be able to make the transition without disruption.
Is this pretty much the way to do it?
I just went through a DC upgrade myself over the holidays. We already used hosted Exchange so I wasn't worried about any issues there.
I have two DCs .10 and .15, with .10 holding FSMO roles and being DHCP server. I first transferred FSMO roles to the .15 server and gave it a day or two. I downloaded the AD Replication Status Tool and verified replication was working as intended.
On a weekend/holiday, I then demoted .10 as DC and changed its IP Address to .11 (this was also our file server so it was staying online a while longer until we migrate it to 2016). I then went into DNS and ensured that all the records were properly updated/removed before proceeding.
I then changed the IP Address of the new DC to .10 and promoted it as DC, DNS, DHCP. Again, I ensured that replication was working properly and that DNS records all got properly updated. Then I backed up my DHCP scope and migrated it to the new DC, and removed DHCP and DNS roles from old DC.
I think I've read in a recent post here that setting up with same IP as old DC isn't recommended, however, I've done it twice now over the years without issue. I would say if you are going the route you mentioned which is to give DC new IP and update this manually across your devices, take the time to make these DHCP reservations so that in the future, all you have to do is update your DHCP scope with the new config and when it renews the leases all the devices will get the updated info automatically.