[noobface]

Active Directory and DHCP go hand-in-hand. Your Domain Controllers aren't always your DHCP servers, but under a certain scale, they very likely are.

[EvanAnderson]

I'm a 20+ year Windows sysadmin and I don't buy it. If you'd said "Active Directory and DNS go hand-in-hand" I'd agree-- the coupling there is pretty tight (and it's a pain-in-the-ass to run Active Directory with non-Microsoft DNS servers being authoritative for the AD domain name). DHCP is a lot less tightly coupled.

[forgotusername6]

If you create a brand new domain, it will automatically configure it to be the DHCP server by default.

[blakes]

That's true of DNS, not DHCP. One has to specifically install the DHCP role in a new AD domain.