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Exchange FAQ

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 Explore the Frequently Asked Questions for Microsoft Exchange.

 Q. What is the flow of the Archibus Exchange Integration?

See the Deployment Options for the Reservations Application to see the data flow.

Q. Is it possible to deliver the Outlook Plugin through the Microsoft Exchange Server Store?
No, it is a COM Add-in for Microsoft Office Outlook on Windows only - this is correct for the Archibus Outlook Plugin for classic Outlook. 
Since v2024.02 an Outlook web add-in is available and the web add-in can be distributed via Exchange.
Q. Does the Meeting Rooms booking component (when integrated to our Messaging System) use Azure ApplicationAccessPolicy to limit Graph API permissions to only Rooms Mailboxes?
Exchange Web Services (EWS)
Yes, when the integration is configured to disable user impersonation (exchange.impersonateUsers=false) and all rooms have a room mailbox in Exchange, the API permission can be limited to the room mailboxes using an ApplicationAccessPolicy. The specific permission required for the integration is "Office 365 Exchange Online" > "Application permissions" > "full_access_as_app".
Microsoft indicates ApplicationAccessPolicy is being deprecated, see New-ApplicationAccessPolicy (ExchangePowerShell). But it is the only way to restrict EWS access.
Graph API
With Graph API the future-proof approach to limit Graph API permissions is using Role-Based access control for applications.
Q. Does the Meeting Rooms booking Registerd App in our tenant use Certificated Based Authentication?
Yes, the integration uses certificate-based authentication.
Q. What is the difference between desktop Outlook Plug-in and the Office365 (web) Outlook Plug-in?
Some differences are:
  • Office365 (web) requires mailboxes.
  • In the desktop plugin, the reservation is created in Web Central before invitations are sent. The web add-in doesn’t create reservations, it only supports finding an available room. The reservation is only created via the monitoring of the room calendars when the room receives the meeting invitation.
  • The web add-in supports Outlook new, Outlook Online, also Outlook new on Mac. The desktop Plugin only works on classic Outlook on Windows.
  • The web add-in is distributed via Exchange Online. The desktop plugin is deployed via MSI.
  • The web add-in connects to Web Central via REST API using OIDC authentication. The desktop plugin connects via SOAP and can only connect to Web Central in SSO mode out of the box.
Q. Can the current (2025.02) Exchange Integration support multi-tenant setup?

Specific setup that works:

The current product can support classic Outlook Plug-In with multiple tenants for deployments that disable user impersonation and have all room mailboxes on the same tenant. In this setup, Archibus only needs to connect to 1 tenant directly, to update and monitor room calendars. 

Further explanation of why other setups are not supported:

The current Outlook 365 web add-in cannot work with multiple tenants because Web Central would need to support validating OAuth tokens from multiple issuers. Each Entra ID tenant is a different issuer.

A workaround to use the Outlook web add-in with multiple tenants is to run a separate Web Central instance (with a different URL but the same database) for each tenant.