We are in the beginning stages of setting up our migration from an on premise Exchange 2010 SP3 server to Office 365 hosting. We have single sign on setup and have setup our Exchange server for the hybrid configuration and federated trust. We can see all of our users in the Office 365 portal and we can see information flowing between Office 365 and our on-premise server.
We are now at the point where we would like to test move a user's mailbox to the cloud service, however, we are running into a roadblock with regard to the MX record. It looks like Office 365 is not recognizing our domain as being valid for email since we haven't modified our MX record to point to Office 365.
So, the short question is, do we need to replace our current MX record and insert the new MX pointing to Office 365? And, if so, will that point all mail to Office 365 (and FOPE) and direct email through the trust for the on-premise mailboxes?