Currently running POSTFIX (lots of boxes doing various tasks). Moving to Exchange without an EDGE TRANSPORT server, just MAILBOX, CAS, and HUB. Keeping Postfix on the perimeter and passing to Exchange.
New Exchange domain (xyz.abc.com) doesn't match existing (non-exchange) mail domain (abc.com). How do I slowly migrate abc.com people to xyz.abc.com and maintain BOTH systems? And still make everything look like abc.com? TO make matters harder, our current POSTFIX system handles 3 different e-mail domains and merging all into Exchange.