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Md. Shamim Reza's avatar
Md. Shamim Reza
Copper Contributor
Jul 06, 2020
Solved

Deploy Hybrid existing Office 365 with new AD and new Exchange server

We have an existing Office 365 portal that have custom domain like abc.com.bd. There are 300 users who already used all Office 365 services including Exchange online.

We have deployed a new AD primary domain abc.com more than 2000 users including existing office 365 users and added UPN suffix abc.com.bd. The new Exchange server domain will be abc.com.bd. We know that we need to match existing Office 365 users and new AD users for same UPN account. This is not my concern.

 

My concern is when we will deploy exchange server using abc.com.bd, mailbox will be created for all AD users. Then a user already has one mailbox in Office 365 and one will be created in an on-premises Exchange server same SMTP address.

 

Now, how we can configure Exchange Hybrid for existing Office 365 user in this scenario?

 

Please any one can share idea and configuration process of Exchange Hybrid in this scenario.

 

Thanks

exchange
hybrid

3 Replies

  • DaniloBelcastro's avatar
    DaniloBelcastro
    Copper Contributor
    Jul 06, 2020

    Hi Md. Shamim Reza,

     

    I think best option could be:

    1. Sync Users with ADConnect
    2. Enable Exchange Hybrid Configuration (I think this configuration could be optional, based on your needs)
    3. For users that already have an Office 365 Mailbox, don't create a mailbox but use powershell command Enable-RemoteMailbox (https://docs.microsoft.com/it-it/powershell/module/exchange/enable-remotemailbox?view=exchange-ps). In this way users should make a soft match (via UPN and ProxyAddress) with those who have mailboxes already present on Exchange Online.

    My advice is if possible to replicate the scenario in a laboratory and test it before going into production.

     

    Best regards

    • Md. Shamim Reza's avatar
      Md. Shamim Reza
      Copper Contributor
      Jul 12, 2020

      DaniloBelcastro Thanks for share the link.

       

      Using the Enable-RemoteMailbox (https://docs.microsoft.com/en-us/powershell/module/exchange/enable-remotemailbox?view=exchange-ps) cmdlet create a new mailbox in the Exchange online for Active Directory sync users.

       

      According my scenario suppose, mailto:user1@abc.com.bd is existing user in Office 365. This user will be created in AD and match to Office 365 as sync user. You mention @For users that already have an Office 365 Mailbox, don't create a mailbox but use powershell command Enable-RemoteMailbox. I appreciate with you. but when I will use Enable-RemoteMailbox cmdlet from on-prem Exchange server for mailto:user1@abc.com.bd that already have an Office 365 mailbox, then what will happen?