This is straigh forward. Here are a few things to look out for:
– AD needs to run Server 2003 native functional mode or higher. Even if you have Server 2008 DC’s, make sure you’ve upgraded the functional mode to at least server 2003 native.
– It’s best practice not to run Exchange 2010 on a Domain Controller. I’ve seen contractors do this in the Exchange 2003 days. It’s not pretty.
– Exchange uses Global Catalogs for domain lookups. If you’ve designed your network to have the domain controllers in a separate VLAN and subnet from Exchange, just add a simple GC to the same subjnet as Exchange.
– Exchange runs 64-bit native. If you have Helpdesk computers that need the Exchange console locally installed, make sure the computers are running a 64-bit OS.
– This is part of the installation process, but make sure to prep the AD forest and domain for exchange. It’s best to do this before installing Exchange. You don’t want errors to occur during the installation.
– If you are worried about branch user authentication during WAN outages, you can deploy a Read-Only Domain Controller at each branch location.