I am planning an Exchange 2003 to 2010 migration. In our current set-up we only have one Exchange 2003 server sitting inside our domain. As part of the migration I want to implement an Edge Transport Server in a DMZ.
There are a lot of moving parts with getting this migration done, and it is my first move to Exchange 2010 (no real experience with 2007) so I would like to move in small steps if possible. My plan right now is to set up the 2010 Exchange server, migrate to it, and then once I have everything working properly and the Exchange 2003 server is decommisioned I would set about configuring an Edge Transport Server after the fact.
Can it be done in this manner, or should it all be done at the same time?