Configuring a Connector for Inbound Email Traffic

You can manually set up a connector for the inbound email traffic in order to only receive emails processed by our services.

You have entered the MX records in the DNS (see: Configuring Microsoft 365 as a Destination Server).

  1. Log in to the Microsoft 365 administration environment.
  2. Navigate to Admin Centers > Exchange > mail flow > Connectors.
  3. Click on New.
  4. Select the point Partner organization from the drop-down menu From:.
  5. Select the point Microsoft 365 from the drop-down menu To:.
    Figure 1: Select destination server
  6. Click on Continue.

    A new window opens.

  7. Enter a name for the connector in the Name field.
    Figure 2: Enter a name
  8. Optional: Enter a description.
  9. Click on Continue.

    A new window opens.

  10. Select the option Use the sender's domain under How do you want to identify the partner organization?.
    Figure 3: Select identification method
  11. Click on Continue.

    A new window opens.

  12. Click on the plus sign under Specify one or more sender domains.

    A window for entering sender domains opens.

  13. Enter an asterisk as a placeholder in the field: *.
  14. Click on OK.
    Figure 4: Asterisk as sender domain

    The previous window opens again.

  15. Click on Continue.

    A new window for entering security restrictions opens.

    Figure 5: Security restrictions
  16. Tick the Reject email messages if they aren't sent over TLS checkbox.
  17. Tick the Reject email messages if they aren't sent from within this IP address range checkbox.
  18. Click on the plus sign and enter the following IP address ranges in the list one after the other:
    94.100.128.0/24      94.100.129.0/24      94.100.130.0/24  
    94.100.131.0/24      94.100.132.0/24      94.100.133.0/24  
    94.100.134.0/24      94.100.135.0/24      94.100.136.0/24  
    94.100.137.0/24      94.100.138.0/24      94.100.139.0/24  
    94.100.140.0/24      94.100.141.0/24      94.100.142.0/24  
    94.100.143.0/24      185.140.204.0/24     185.140.205.0/24  
    185.140.206.0/24     185.140.207.0/24     173.45.18.0/24   
    83.246.65.0/24
  19. Click on Continue.

    A new window with an overview of your settings opens.

    Figure 6: Settings of new connector
  20. Click on Save.

    Your settings are checked. The connector is saved. A confirmation message is displayed.

    Figure 7: Connector successfully saved
  21. Click on OK.
    The window closes. The new connector is displayed under Connectors.

A connector for the inbound email traffic has been configured.