Calendar free/busy sharing between 2 hybrid Exchange environments RRS feed

  • Question

  • Hi,

    For a client, I'm trying to set up free/busy sharing for their meeting rooms (resource mailboxes). They have 2 completely separated environments, without domain trust. Both have a Hybrid Exchange environment where users were created on-prem and later moved to the cloud. 

    • Both environments have a federation sharing with Azure.
    • In the cloud, there is an Organization Sharing configured - limited to a security group containing the resource mailboxes.
    • The mailboxes were configured to accept External Meeting requests.

    At this moment, a user in company B can book the meeting room in company A by adding the resource mailbox e-mail address to a new meeting. He receives confirmation but is unable to see free/busy info in the scheduling assistant.

    What I'm trying to achieve is that free/busy information from the resource mailboxes in company A is shared, and that only to a group of users in company B. I understood that this could be achieved by "Issuance claim rules"? 


    Monday, February 4, 2019 9:57 AM

All replies

  • I changed the thread type to Question because you're asking one.

    You said you have two hybrid configurations.  For each organization do you have mailboxes both on-premises Exchange and Exchange Online?

    Issuance claim rules are for AD FS and don't apply here.

    Here's the documentation on how to set up interorganizational free/busy sharing.


    Please feel free to post if you have any specific questions.

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

    Tuesday, February 26, 2019 2:25 AM