How to Configure Microsoft 365 Outbound Automatic Replies

Use the steps in this article to configure outbound automatic replies that do not have an Envelope-From address or have an Envelope-From domain not in Email Gateway Defense (such as onmicrosoft.com) . This ensures that relayed mail and mail without an Envelope-From is sent directly to the internet bypassing Email Gateway Defense.

Step 1. Create the Connector

Note that the following steps use the new Exchange admin center user interface.

1. Log into the Microsoft 365 admin center https://admin.exchange.microsoft.com/.
2. In the left pane, click Mail flow, and click Connectors.
3. Click the Add a connector button, and use the wizard to create a new connector.
4. For Connection from, select Office 365. For Connection to, select Partner organization.
   
5. Click Next. Enter a Name and (optional) Description to identify the connector:
   
6. Click Next. Select Only when I have a transport rule set up that redirects messages to this connector.
   
7. Click Next. Select Route email through these smart host, and click the + symbol.  
   1. Go to Email Gateway Defense, and click the Domains tab. Copy your outbound hostname from the MX records, and enter it in the add smart host page:
      
8. Click Next. Use the default settings for the Security restrictions:Always use Transport Layer Security (TLS) to secure the connection (recommended) > Issues by Trusted certificate authority (CA):
   
9. Enter an external email address to validate the connector. For this test, it is important to use an email address from outside your organization , like a gmail or yahoo email address. Click Validate. 
   There are two parts of the validation:
   
   1. Test Connectivity – If this test fails, Outbound Groups is not enabled. Contact Barracuda Networks Technical Support and request that Outbound Groups be enabled on your Email Gateway Defense account.
   2. Send Test Email – If the test fails, there is no cause for concern. The test email comes from a Microsoft domain, not from your domain, so it is rejected. If you changed your domain away from onmicrosoft.com, the test should work. Note that you might still receive the email even if the test failed. 
   
10. Once the validation process is complete, click Next. Review your settings and then click Create connector.

Step 2. Create Transport Rule

1. Log into the Microsoft 365 admin center https://admin.exchange.microsoft.com/.
2. In the left pane, click mail flow, and click rules.
3. Click Add a rule.
4. Select Create a new rule.
   
5. In the new rule page, enter a Name to represent the rule.
6. Under Apply this if, select The sender > is external/internal > Inside the organization.
7. Click the + to add a new condition.
8. From the drop-down menu, select The recipient > is external/internal > Outside the organization.

9. Under Do the following, select Redirect the message to > the following connector, and select the connector you defined above in Step 1. Create the Connector.

10. Under Except if, select The message properties > include the message type > Automatic reply.

    

    You can only set one message type exception per rule. You must create multiple mail flow rules for different message types, for example, one for Automatic reply and one for Auto-forward.

    

     

11. Click Next.

12. Under Match sender address in message, select Header or envelope.
    

13. Click Next.
14. Review the settings and then click Finish.
    

Step 3. Disable Existing Barracuda Networks Send Connector

1. Log into the Microsoft 365 admin center https://admin.exchange.microsoft.com/.

2. In the left pane, click mail flow, and click connectors.

3. Select the send connector you created during Step 2 - Configure Microsoft 365 for Inbound and Outbound Mail, Step 7. Configure Outbound Mail section.

4. Disable the send connector. 

Your system will now use the new send connector you created in Step 1 above.