AADconnect with Exchange server but without Hybrid Config - Managing users

LIT-RS 1 Reputation point
2021-02-08T18:44:28.813+00:00

Hi,

We have all of our mailboxes in Exchange Online. MX records point to Exchange Online. Autodiscover points to Exchange Online (autodiscover.outlook.com).
These were migrated to O365 from a previous project (previous supplier).

I have a new on-premises Active Directory forest. I have configured AADConnect server and will be syncing my new AD users to Azure.
I will also be hard matching the Exchange Online mailboxes to my on-premises AD users (using immutableID command. Not an issue).

As I have installed a new Exchange 2016 environment, I want to see the Exchange Online mailboxes visible in my on-premise Exchange ECP.
I want to do this without having to set up a Hybrid Configuration. The reason is, There is no need for Free/Busy, no need for mail to route across on-prem and EXO - because, Autodiscover points to Outlook.com, MX records point direct to Exchange Online.

I just want to be able to see the Exchange Online mailboxes displayed as "Office 365" mailboxes in my on-premise Exchange 2016 so IT admin team can do BAU activities such as changing Exchange related attributes (e.g. hide from address list) etc from on-prem. Or even be able to create a new remote mailbox from Exchange on-prem.

Thanks
Ron

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  1. Lucas Liu-MSFT 6,161 Reputation points
    2021-02-09T08:18:57.693+00:00

    Hi @LIT-RS ,
    According to my research and test. Although there is no official documentation, if you want to manage mailboxes in Exchange online in the on-premises EAC, I think hybrid deployment is necessary.
    The following are the specific steps I tested in the lab environment, hope it can help you:
    1.Same as you stated, create a new AD account in Active directory Users and Computers(ADUC). then use SMTP matching to match on-premises user accounts to Office 365 user accounts for directory synchronization.
    For more information you could refer to: How to use SMTP matching to match on-premises user accounts to Office 365 user accounts for directory synchronization

    2.Connecting a PowerShell session to Office 365 Exchange Online. Then run the following command to get the ExchangeGUID of the Exchange online mailbox.

    Get-Mailbox user | fl ExchangeGuid

    3.Then runt the following commands to create the remote mailbox and set the GUID to remote mailbox in EMS in on-premises Exchange server:

    Enable-RemoteMailbox <> -RemoteRoutingAddress <>  
Set-RemoteMailbox <> -ExchangeGuid <>

    4.Please login to EAC and check whether you could see the Exchange Online mailboxes displayed as "Office 365" mailboxes in on-premise Exchange server.

    5.However, when I edit the mailbox type of Office 365 in the on-premises EAC. For example, set the city to "test1". I found that the mailbox information in Exchange online has not changed, and the object information of type "Mail user" in the contact has changed. It can be seen that the object in the on-premises EAC does not correspond to the mailbox in Exchange online, but the object in contact.

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    1 person found this answer helpful.
  2. Andy David - MVP 142.2K Reputation points MVP
    2021-02-08T18:50:45.703+00:00

    You'll have to enable all the existing accounts as remote mailboxes.
    Ensure you have set the correct primary SMTP addresses on those accounts and I would set the alias the way you want so that syncs
    The remote routing address will sync to the 365 object.

    Enable-RemoteMailbox "Kim Akers" -RemoteRoutingAddress "kima@Company portal .mail.onmicrosoft.com" -alias <alias>

    My assumption is that these on-prem accounts so not show as mail-enabled now.

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