Delegating a mailbox to another domain forest.


Hello. There are two forests.

How to delegate a mailbox from domain B, to domain A ? There is a two-way trust relationship between them.

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.
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  1. Zhengqi Lou-MSFT 8,816 Reputation points Microsoft Employee

    Hi @Андрей Михалевский ,

    Based on my research and tests, I think the Exchange server doesn't provide the function of delegating user A mailbox to user B who is from another forest.
    I tried the linked mailbox, cross-forest mail contact and so far there are no methods could working for our case. They all failed with "You don't have permission to open this mailbox".

    I find one article that's about cross forest delegation using the Outlook client to sync their calendar on Exchange 2010: Exchange Server 2010 Cross Forest Delegation
    And here is a similar case about Exchange Cross Forest Shared mailbox delegation, hope those could help.

    Best regards,

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  1. 2021-07-12T10:17:56.707+00:00

    Thank you. I get it, it's not possible.