Configure Microsoft 365 to use a smarthost

In order to route all outbound mail through MX Guardian, you must configure Microsoft 365 to use a smarthost. This guide will walk you through creating a new Send Connector and configuring it to route outbound mail to MX Guardian. 

Note: Make sure outbound filtering is enabled on your account before following this procedure.

1. Open Exchange Admin Center
2. Click on Mail Flow
3. Click on Connectors
4. Click Add a connector
5. Select the following options and click Next
   
6. Give the connector and name and click Next
7. Select Only when messages are sent to these domains
8. In the box below, enter a single asterisk (*) and click the plus icon. Then click Next.
9. Select Route email through these smart hosts
10. Enter smtp.mxguardian.net in the box below and click the plus icon. Then click Next.
11. Click Next on the Security Restrictions page to accept the defaults
12. On the Validation page, enter an external email address (outside your organization) and click the plus icon. Then click Validate
13. Once the validation succeeds, click Next
14. On the Review Connector page, click Finish

Your domain is now configured to route outbound mail to MX Guardian. You should begin seeing messages appear on the Outbound tab in the MX Guardian control panel.