Hi guys,
We have Exchange 2013 on premise, working fine, serving users with our main domain. (domain.com)
We also have a separate Office365 tenancy, with a subset of users that have a subdomain (sub.domain.com). These users logon to Office365 with credentials stored on just Office365 - they are not federated with our on-premise Exchange / AD.
We are now looking at merging these two environment e.g. moving to a true Hybrid, with the goal being that the users we have on Office365 can have our primary domain as an email address (domain.com) as well as their current subdomain address.
There doesn't seem to be much online about this - it's a slightly unusual situation... If I was to implement the usual plan of ADFS and DirSync and integrate our on-prem, what happens to the existing accounts on Office365? Would they stay as authenticating as they are - e.g. against the current MS accounts? If so can I move them so they are authenticated using an AD user object via federation? How would one do this? Would this just "magically" happen if there is a matching AD user object, could I match the account using the GUI or would I need to run a PowerShell command?
Thanks - Steve