On Premise Exchange Server after wonky migration to Identity Hybrid

Lipschutz, David 1 Reputation point
2021-03-12T21:49:27.373+00:00

We were hit with a ransomware attack back in 2019 and lost our Exchange Server 2016. We synced our users from Active Directory to 365 and gave them new mailboxes. Then, we reinstalled Exchange 2016 and restored our old mailboxes. We migrated users' messages from their old mailboxes on the restored-on-premise-server to their new 365 mailboxes. What does this give us? “Identity Hybrid”? The on-premise Exchange server is 2016 with CU19 installed on Windows 2016. It still has all the server roles and footprint as when it was a mailbox and transport server. I’m not confident in my AD setup as far as Exchange is concerned. I’d like to get that disk space back and clean up my environmCan ent. Can I remove the old unused mailboxes and the any link from the AD accounts to them? Can I remove the unused server roles from the server and from Active Directory. Can I migrate the 2016 server to a new server Exchange 2019 on Windows 2019 with only with only the hardware and functionality needed for “Identity Hybrid”? Or decomission the server and install a 2019 server on-premise for management?

Sorry if I got the tags wrong, or composed the descripton of this mess poorly

Microsoft Exchange Online Management
Microsoft Exchange Online Management
Microsoft Exchange Online: A Microsoft email and calendaring hosted service.Management: The act or process of organizing, handling, directing or controlling something.
4,151 questions
Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
7,326 questions

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  1. Joyce Shen - MSFT 16,641 Reputation points
    2021-03-15T06:09:19.997+00:00

    Hi @Lipschutz, David

    The official document here introduced about the What is hybrid identity with Azure Active Directory?

    What migration method did you use to finish this? "We migrated users' messages from their old mailboxes on the restored-on-premise-server to their new 365 mailboxes."

    Did you run the HCW to deploy a hybrid between your on-premise Exchange server and O365?

    And now the mailboxes are located in cloud and they still use AAD connect to sync from on-premise right? Correct me if I have any misunderstanding about your environment.

    If you run HCW before to deploy a hybrid, and you have all of mailboxes in Exchange Online. Do not need to manage my users from on-premises and no longer have a need for directory synchronization or password synchronization. Refer to the Scenario one in this official document.

    If you didn't deploy a hybrid previously, refer to this link: Convert Synced user to In Cloud Only User Account on Office365

    Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.

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  2. Lipschutz, David 1 Reputation point
    2021-03-23T21:40:09.767+00:00

    I really can't remember how we migrated the messages.
    I think some sort of export / import.
    Can remember how we got Hybrid set up either.
    I don't think it was the wizard.
    There is a mailbox in the cloud currently used, and an unused mailbox containing the migrated messages on-premise, for each user.
    I will follow your provided links asap.
    I thought I had some time carved out when I posted this.

  3. Lipschutz, David 1 Reputation point
    2021-03-26T14:40:13.91+00:00

    I am Scenario two.
    I am digesting the article
    My public folders are migrated but the on premise server still says.
    PublicFoldersEnabled : Local

    I'll keep reading

    0 comments
  4. Lipschutz, David 1 Reputation point
    2021-03-29T16:04:36.533+00:00

    https://learn.microsoft.com/en-us/exchange/troubleshoot/user-and-shared-mailboxes/mailbox-exists-exo-onpremises
    From this article, I am able to
    Disable-Mailbox "mailbox identity"
    then
    Enable-RemoteMailbox "user identity" -RemoteRoutingAddress "user@Company portal .mail.onmicrosoft.com"
    That leaves me seeing the user as "Mailbox Type" "Office 365" on my on premise server ecp.
    I think that is what I need to do, right?
    But now I will need to do that for ALL my users.

  5. Lipschutz, David 1 Reputation point
    2021-04-04T16:54:13.77+00:00

    All mail flow is as expected.
    No issues there.
    I think this would work for me other than any aliases.
    I would also need my account creation to handle the enable-remotemailbox.

    Disable-Mailbox "mailbox identity"
    then
    Enable-RemoteMailbox "user identity" -RemoteRoutingAddress "user@Company portal .mail.onmicrosoft.com"
    That leaves me seeing the user as "Mailbox Type" "Office 365" on my on premise server ecp.
    I think that is what I need to do, right?
    But now I will need to do that for ALL my users.