We are migrating mailboxes from a SBS2003 server to an Exchange 2010 server that we just installed this week. These mailboxes have multiple email addresses associated with them. About six months ago they purchased and started publishing to the world a new domain name but continued to use their old domain name. I found that I could not setup their IPhones to sync with the new Exchange 2010 using the Reply To email address (which are the email addresses with the new domain) but had to use the email address they were using before.
I guess this isn't an issue until they want to totally get rid of the old email address. Can someone help me figure out what needs to be configured so I can use the email addresses with the new domain to configure the IPhones?