Microsoft 365's hosted service for mail, calendars and contacts. Defender for Office 365 protects these mailboxes.
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In the Ultra Transcenders books
Each book explains Exchange Online in context, with comparison tables and the common traps.
Terms in this definition
- Microsoft 365
Formerly Office 365, Microsoft's software-as-a-service productivity suite. A Microsoft Entra tenant provides its identity, and its data is not governed by Azure RBAC.
Related terms
- Application-enforced restrictions
Lets Exchange Online or SharePoint Online learn whether a device is managed and compliant: on such devices users get everything, while elsewhere they get a cut-down experience such as browser-only access. It is a Conditional Access session control.
- Auto-mapping
An Exchange Online feature that adds a mailbox to a person's Outlook by itself once they're given Full Access directly. Granting that permission via a group doesn't trigger it.
- CAE
Instead of letting an access token run until it expires, Microsoft Entra continuous access evaluation allows Microsoft Graph, Teams, SharePoint Online, Exchange Online and similar services to end a session almost straight away. Triggers include a disabled account, a password reset, revoked tokens, high user risk or a move to a different network location.
- Dynamic Delivery
A Safe Attachments option where the body of a message reaches the recipient straight away, with placeholder files standing in until the attachments have been scanned. It is only available for mailboxes in Exchange Online.
- Dynamic distribution group
A mail group in Exchange Online that works out its own membership from attributes such as company or department, recalculating at least daily. It never reaches Microsoft Entra ID, so Conditional Access policies can't target it.
- EOP
Exchange Online Protection, the established name for the security built into every cloud mailbox in Exchange Online: filtering against malware, spam and spoofing. Defender for Office 365 adds to it.
- Equipment mailbox
An Exchange Online resource mailbox for bookable items that aren't locations, like a company car or projector, reserved by including it in a meeting request. Admins find it, together with room mailboxes, under Recipients > Resources.
- Exchange ActiveSync
A protocol some phone and tablet email apps rely on for syncing mail. Conditional Access classes it as legacy authentication, so policies aimed at it should be scoped to Exchange Online alone.