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exchange on prem to online migration RRS feed

  • Question

  • Hi guys,

    Just a question:

    We are in the process of migration our 2016 HA exchange environment to exchange online.  Our hybrid deployment is working, we already successfully migrated some pilot mailboxes(including mine*) to EO. autodiscover does his job and all is getting redirected.  still using the on premise emaillpolicies,... 

    now what our goal is or should be... is to decommision the on premise exchanges, this possible?, i read some articles you still need an exchange on premise? someone can confirm?

    When a new user joins the company, i tested to create the mailbox in exchange online instead of on premise (so i dont need to migrate it afterwards..), so i noticed the mail attributes are not coming in our on premise AD, something we miss here to get that attributes filled in or is this not necessary?

    greetings 

    thx already

    Tuesday, January 15, 2019 1:19 PM

Answers

  • For your questions:

    1. now what our goal is or should be... is to decommision the on premise exchanges, this possible?, i read some articles you still need an exchange on premise? someone can confirm?

    We could get the answer in the following article: 
    How and when to decommission your on-premises Exchange servers in a hybrid deployment

    If all of the users will be managed in Office 365, and there are no additional directory synchronization requirements, you can safely disable directory synchronization and remove Exchange from the on-premises environment, otherwise it would be the best to retain at least one on-premises Exchange server in a hybrid environment.

    2. When a new user joins the company, i tested to create the mailbox in exchange online instead of on premise (so i dont need to migrate it afterwards..), so i noticed the mail attributes are not coming in our on premise AD, something we miss here to get that attributes filled in or is this not necessary?

    If the mailbox is created in the cloud, then there is not an associated account in on-premises AD, am I right?

    In this case we need to match the cloud identity to an on-premises user. To achieve this, follow the steps in the KB article linked below:

    How to use SMTP matching to match on-premises user accounts to Office 365 user accounts for directory synchronization -- How to use SMTP matching to match an on-premises user to a cloud identity

    Then the account can be managed through an on-premises AD user account by using directory synchronization, while this doesn't mean all the mail attributes will be written back to on-premise Exchange, and SMTP matching can be used only one time for user accounts that were originally authored by using Office 365 management tools. After that, the Office 365 user account is bound to the on-premises user by an immutable identity value instead of a primary SMTP address.

    Hope it helps.

    Regards,

    Manu Meng


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

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    Wednesday, January 16, 2019 7:48 AM
    Moderator

All replies

  • If you're going to keep using Azure AD Connect to keep your directories in sync and/or for single sign-on, then you'll want to keep your on-premises hybrid server in place so that you can continue to perform recipient administration in a supported way.  If you have on-premises SMTP senders sending mail to internal cloud recipients, the on-premises server does that better as well.

    You should be creating the mailbox in on-premises as a remote mailbox (New-RemoteMailbox, or New > Office 365 Mailbox in the EAC).  After synchronization, and licensing the user in Office 365, a cloud mailbox is created.  You don't need to create the mailbox on-premises and move it.


    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."
    Celebrating 20 years of providing Exchange peer support!

    Wednesday, January 16, 2019 7:34 AM
    Moderator
  • For your questions:

    1. now what our goal is or should be... is to decommision the on premise exchanges, this possible?, i read some articles you still need an exchange on premise? someone can confirm?

    We could get the answer in the following article: 
    How and when to decommission your on-premises Exchange servers in a hybrid deployment

    If all of the users will be managed in Office 365, and there are no additional directory synchronization requirements, you can safely disable directory synchronization and remove Exchange from the on-premises environment, otherwise it would be the best to retain at least one on-premises Exchange server in a hybrid environment.

    2. When a new user joins the company, i tested to create the mailbox in exchange online instead of on premise (so i dont need to migrate it afterwards..), so i noticed the mail attributes are not coming in our on premise AD, something we miss here to get that attributes filled in or is this not necessary?

    If the mailbox is created in the cloud, then there is not an associated account in on-premises AD, am I right?

    In this case we need to match the cloud identity to an on-premises user. To achieve this, follow the steps in the KB article linked below:

    How to use SMTP matching to match on-premises user accounts to Office 365 user accounts for directory synchronization -- How to use SMTP matching to match an on-premises user to a cloud identity

    Then the account can be managed through an on-premises AD user account by using directory synchronization, while this doesn't mean all the mail attributes will be written back to on-premise Exchange, and SMTP matching can be used only one time for user accounts that were originally authored by using Office 365 management tools. After that, the Office 365 user account is bound to the on-premises user by an immutable identity value instead of a primary SMTP address.

    Hope it helps.

    Regards,

    Manu Meng


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

    Click here to learn more. Visit the dedicated forum to share, explore and talk to experts about Microsoft Teams.

    Wednesday, January 16, 2019 7:48 AM
    Moderator