I am going to be migrating from exchange 2007 which is running on an SBS 2008 box to Exchange 2010 which will be running on a Windows 2008 R2 box. The process is pretty straight forward. However, I do have a few questions:
Some of the guides I've read are instructing me to change my firewall to direct port 25 traffic to the new exchange 2010 server BEFORE I've even moved any mailboxes. Is that right? Why would I try to deliver 25 traffic to my new server before any mailboxes are moved to it - or is exchange 2010 smart enough to know that the mailboxes still reside on the sbs 2008 server?
I'm concerned about what happens after I move a mailbox. First, when that user launches outlook for the first time, what happens? Is outlook/exchange smart enough to see that the mailbox has moved to the new server and outlook automatically points to the new server? Also, what happens to mobile devices like phones, once I move a mailbox? Will that break their mobile phone until I point OWA traffic to the new server? What happens if I were to point 443 traffic to the new server BEFORE I started moving mailboxes (same thinking as changing port 25 traffic before I start moving mailboxes).