Q:

How Exchange integrates with DC

This probably is a very open ended question, but really I'm only looking for a specific aspect I suppose. It relates to a reboot question I posted earlier, relating to restart orders of servers, Server Restarts and Respective Orders. Please take a look if you get a second for input!
Basically - in relation to how Exchange integrates with AD, what would happen in two scenarios:
1). The Exchange server is booted up before the DC is online
2). You replace a DC but keep your current Exchange server.
I'm fairly new to all of this, so hopefully this isn't a silly question (I'm an apprentice in fact!).
Many thanks

A:

Exchange needs to be able to connect to Active Directory, and to Global Catalog servers. If those are not reachable (for example, by only having one DC that's down), Exchange will have problems. Those problems should go away when the DC/GC is back up.
If you're replacing a DC that is the only DC in your domain, you can't have the first one down before the new one is promoted, so that scenario can't happen. dcpromo the new one, make it a GC, point Exchange at it, take the old one down (or, for heaven's sake, leave it running, because now you have 2 DCs.)

