Prior to migrating your DHCP servers from Windows Server 2003 to Windows Server 2012 R2, you’ll need to get a good idea of what your DHCP deployment looks like. Just so that you can be sure that you don’t miss anything.
The first, and perhaps easiest, question to deal with is “how many DHCP servers do I have”. DHCP servers are, for the most part, loners on most organization’s networks. It’s only with the introduction of Windows Server 2012 that you can centrally manage DHCP settings and scopes through the included IPAM feature (though there are 3rd party products out there that can do the same thing).
Many organizations have 2 DHCP servers handling the duties for a single scope, with one DHCP server hosting 80% of the addresses and another hosting 20% of the addresses. You’ll need to look at the scopes you use and figure out how they are split across existing DHCP servers.
You’ll also need to ensure that you have documented scope level options and server level options. While there is a method of migrating everything from one DHCP server to another, you’ll need to have everything documented in case something goes wrong and you have to rebuild it from scratch.
In the next post, I’ll discuss how you can migrate DHCP servers from 2003 to 2012 R2.