Exchange Online · Mail Flow
Remote and Accepted Domains
Manage remote domains, accepted domains, and connectors that define valid email domains and how external domains are treated.
Scope: Email domains and external domain handling
Permissions
- Add and remove accepted domains
- Configure domain types (Authoritative, Internal Relay, External Relay)
- Manage remote domain settings
- Configure message format for external domains
- Set default reply domain
Common use cases
- Adding new email domains to the organization
- Configuring subsidiary or additional domains
- Managing message format for partner domains
- Setting up domain-based mail routing
Best practices
- Verify domain ownership in Microsoft 365 admin center first
- Use Authoritative for domains where all recipients exist in Exchange Online
- Use Internal Relay for hybrid scenarios with on-premises recipients
- Configure remote domain settings for trusted partners
Security considerations
- Incorrect domain configuration can affect mail delivery
- Internal Relay domains can forward mail externally
- Remote domain settings affect auto-replies and message format