You can use this article to connect an on-premises Microsoft Exchange environment to Rainbow calendar presence. It explains how Exchange calendar events and out-of-office information become visible in Rainbow without relying on Microsoft 365 cloud services.
Purpose
Exchange calendar synchronization lets Rainbow display user calendar availability and out-of-office information without relying on cloud-based Microsoft 365 services.
Prerequisites
- On-premises Microsoft Exchange 2016 or later, reachable through EWS.
- A dedicated Exchange service account with ApplicationImpersonation RBAC role on monitored mailboxes.
- Network connectivity from the connector host to the Exchange EWS endpoint, typically HTTPS 443.
- Users to be covered must have the
canSynchCalendarprofile flag. - At least one configured Rainbow email identifier must match the Exchange mailbox domain.
Configure Exchange in Rainbow Web Admin
Exchange settings live under Company - Application, separately from LDAP user and directory synchronization. Select Exchange as the calendar backend, then fill the configuration form.
| Field | Purpose |
|---|---|
| API endpoint | Exchange Web Services URL, for example https://mail.example.com/EWS/Exchange.asmx. |
| Client ID | Exchange service account login. Despite the label, this is not an OAuth client identifier. |
| Client secret | Exchange service account password. |
| Email identifier list | Ordered Rainbow user attributes used to match a user to an Exchange mailbox. |
| Notification token | Opaque token sent in notifications so Rainbow can validate the source. |
User eligibility and subscription
Subscription is automatic. The connector considers Rainbow users with the canSynchCalendar flag, tries configured email identifiers, verifies mailbox access and subscribes valid mailboxes.
Runtime behavior
- On connector restart, Exchange subscriptions are re-established and user calendar status is refreshed.
- If the Exchange streaming connection drops, the connector retries and re-subscribes automatically.
- Out-of-office data is retrieved on demand and at connector startup for a bulk refresh.
Known limitations
- Supported Exchange flavor: on-premises Exchange 2016 and later through EWS.
- Single email domain matching; multi-domain Exchange organizations are not supported.
- Out-of-office HTML formatting is stripped to plain text.
- Appointment times use the timezone of the Windows host running the connector.
- OpenXchange and Exchange configurations are mutually exclusive for the company.