Forum Discussion
Azure AD Connect and "Exchange hybrid deployment" write-back
Why the need not to writeback?
If you have mailboxes both and in 365, you'll want that writeback enabled.
For example the legacyExchangeDN of a moved mailbox is written back as an X500 address on-prem to the remote mailbox .
If you dont have that, its going to cause issues for your Outlook clients with cached values and public folders.
Can the Exchange Hybrid writeback option be chosen at a later stage in AD Connect when the organization is ready to implement Exchange Hybrid and perform migrations?
Enabling Exchange hybrid deployment in AAD connect allows Exchange Online and Exchange on-premise to learn where exactly the mailbox is hosted. If this is not turned on and if a license that allows an Exchange mailbox is assigned to the user in O365, let's say an E3, a mailbox will be provisioned in O365. To avoid this situation, it makes sense to do so before license allocation in O365. Another option is to select specific services under the license to avoid creating a cloud mailbox if you want to consider enabling this optional feature at a later stage.
Cheers,
Azhar Syed
