Migration to Exchange 2007 from 2003

hello, I currently have one exchange server 2003 along with domain controller and dns server > all on one server. We are running a company of 15 people and find no need in separating them out. I am trying to Migrate to exchange 2007. I have followed some instructions on how to migrate http://www.msexchange.org/tutorials/Transitioning-Exchange-2000-2003-Exchange-Server-2007-Part1.html I am confused on what will happen to my active directory. Do I need to transfer first my active directory on my new server or I will keep the old server as mine domain controller. Or do I add my exchange 2007 server as a second DC? Thanks in advance, Roman

If you want to keep your old Exchange 2003 server around as a domain controller. You do not need to promote the new Exchange 2007 to be a DC. If you want to remove your old exchange server completely you will want to promote the 2007 server to be a DC and GC and then move the FSMO roles.

 Its really up to you on how you want to do it.

And that is exactly how I would do it. When you are done, you will have your DC/GC on 1 server and Exchange 2007 on another. After you remove exchange 2003 from that server, it will still remain as DC/GC.