Exchange hybrid deployments with multiple forests and moving mailboxes

Question

Hello,
I would like to implement an Exchange hybrid deployments with multiple forests.
Currently there are two forests company a and company b that are in trust with each other and each has an exchange server.
An exchange hybrid has already been configured for company a and now I would like to hybrid also with the exchange of company b. It's possible?
Once both exchanges are hybridized, since I would like to dispose of the forest of company a, I would like to ask if it is possible in some way to link the mailboxes of company a to the users of company b.
I would like to do this as I would like to unify all users and mailboxes under the company forest b.
It's possible?

Thanks

Greetings

Answer 1

@pazzoide76

Exchange online hybrid with two forests is supported. But you need to change the topologies of AAD Connect first:

About link mailboxes in hybrid, you could have a look about this article: EXCHANGE RESOURCE FOREST AND OFFICE 365 – PART IV

Personally, I suggest you merge the two forests, which will facilitate the management and deployment of hybrids：

• After adding domain B in forest A "Active Directory Domain and Trusts", you will could use domain B as logon name in forest A.
• Then, add the domain B as an accepted domain in forest A Exchange, you will could use domain B as email address for forest A mailbox.

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