Overview

The Exchange Connectors tab lists every inbound and outbound mail flow connector configured in your client's Exchange Online environment. Connectors control how email flows between Microsoft 365 and external mail servers, partner organizations, or on-premises environments.

Connector Types

The tab is split into two sections.

Inbound connectors

Inbound connectors define how email from external sources is received into the Microsoft 365 tenant. Common uses:

• Receiving mail from an on-premises Exchange server
• Routing mail through a third-party email security gateway
• Accepting mail from a partner organization with specific TLS requirements

Outbound connectors

Outbound connectors define how email is sent from Microsoft 365 to external destinations. Common uses:

• Routing outbound mail through an on-premises server or gateway
• Enforcing TLS encryption for specific partner domains
• Sending mail through a third-party filtering service

Security Notes

Misconfigured or unknown connectors can be a significant security risk. They can:

• Let mail bypass spam and malware filtering
• Create open relays that can be exploited for phishing
• Route sensitive mail through unintended third-party services

Review connectors regularly to make sure mail flow is secure and intentional.

Related Articles

• Drift Detection
• Conditional Access Policies