Exchange Connectors

The Exchange Connectors tab displays all inbound and outbound mail flow connectors 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 page is divided into two sections:

Inbound Connectors

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

• 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 use cases include:

• 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

Why It Matters

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

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

Reviewing connectors regularly helps ensure mail flow is secure and intentional.