Exchange Resource Domain for 6 Different Forests


  • Hello all,

    We are going to consolidate all of the Exchange domains that we administer into 2 servers (using DAG across 2 Datacenters). We currently have 6 different forests, each with 1 domain, and each running their own Exchange server. 3 of the forests (Forests A, B, C) have a 2-way transitive trust to a 4th but not with each other (i.e. ForestA<-->ForestZ, ForestB<-->ForestZ, and ForestC<-->ForestZ). The other 2 forests are segmented from all others (including each other) via a firewall and do not have any trusts.

    How could we accomplish a consolidated Exchange infrastructure where Forests A, B, C, D, and E can communicate and update against Forest Z? We have thought through a few scenarios and have agreed that a resource domain inside of Forest Z might be the solution, but I think that forest-level trusts would inhibit Forests D and E from communicating into the forest (provided we allow the appropriate ports through the firewall).

    Thursday, January 12, 2017 8:59 PM

All replies

  • Hi,

    When I see your current configuration , I think that the best choice is to make Forest Z as resource forest where you can install you new Exchange organisation , because the forest trust is already created with the other forests .

    You can also use linked mailbox if you would like that all users from different forest keep same account  to logon on computer after mailbox migration. 

    You check the following link more information :  Manage linked mailboxes
    Thursday, January 12, 2017 10:13 PM
  • Your scenario is not clear but I assume that you will migrate your objects to Forest Z. If yes then you can use ADMT to migrate AD objects and I would advise to ask them in Exchange forums to see how to migrate your mailboxes:

    This posting is provided AS IS with no warranties or guarantees , and confers no rights.

    Ahmed MALEK

    My Website Link

    My Linkedin Profile

    My MVP Profile

    Thursday, January 12, 2017 10:22 PM
  • Hi,

    I am checking how the issue going, if you still have any questions, please feel free to contact us.

    And if the replies as above are helpful, we would appreciate you to mark them as answers, and if you resolve it using your own solution, please share your experience and solution here. It will be greatly helpful to others who have the same question.

    Appreciate for your feedback.

    Best regards,


    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact

    Friday, January 20, 2017 9:34 AM