My company has been acquired and I have been tasked with merging the two mail systems. The end goal is that my company’s domain goes away, however this will take time to complete and the number one priority is to allow users still in the old domain to send and receive mail with the new domain. My company runs Exchange 2013 and the company that acquired us runs Exchange 2007. They are in the process of upgrading their system to Exchange 2013, but before that will complete, the old company needs the ability to send and receive as the new company. For all examples, my company will be “olddomain.com” and the company that is acquiring us will be “newdomain.com”.
My first thought was to just create all olddomain.com users in newdomain.com and give them all 2007 mailboxes. Since the end game is that olddomain.com goes away, I think we could live with the multiple credentials/sign-ons temporarily… the big downside of that to me is, we’d have to export all mail from the 2013 DB’s to .pst and then import them to 2007. With over 150 mailboxes and 500GB of mail, this doesn’t seem feasible.
My next thought was to create all olddomain.com users a mailbox in newdomain.com, then set the mailboxes to forward to the olddomain.com email address. Then create contacts in each organization for all users in the other. I like this plan, but the overhead of managing the contacts seems too much. Having to add a contact in both organizations every time an employee is added… leaves a lot of room for error.
Lastly, I looked at SMTP Name Space sharing… but I’m not sure if this solution would meet our goals, since I do not want a new namespace, rather to share the existing one.
I’m looking for any suggestions or experiences from anyone with knowledge on this subject.