[Email DLP] Connection Procedure (Microsoft 365)

Overview

This article explains the procedure for connecting Microsoft 365 (Exchange Online) so that emails sent to external recipients are routed through Email DLP for customers using Microsoft 365 (Exchange Online).

Notes

1. After completing this connection, the email delivery route will change. Please carefully consider the scope of impact and the timing of this work before proceeding.
2. The content of this article is based on product specifications as of July 2026 and may be subject to change without notice.
3. You must register the SPF record before performing this connection.
   Add Email DLP SPF Record
4. To confirm the effect on email routing, if there are any existing settings in the following sections, please take a screenshot showing the settings or use the PowerShell commands below to obtain the information and send it to us before proceeding.
   ・[Exchange admin center] Left menu [Mail flow] - [Rules]
   ・[Exchange admin center] Left menu [Mail flow] - [Connectors]

Reference: How to check mail flow and connectors using PowerShell+

Procedure

1. Access the Exchange admin center.
   https://admin.cloud.microsoft/exchange (external link)

2. Go to [Mail flow] - [Connectors] and click [+ Add connector].

   

3. Select the following information and click [Next].

   • [From]: "Office 365"
   • [To]: "Partner organization"

   

4. Set the following values and click [Next].

   • [Name]: HENNGE Email DLP
   • [What do you want to do after saving the connector?]: Check [Turn it on].

   

5. Select [Only when a transport rule is set up to route messages through this connector], then click [Next].

   

6. Set the following values and click [Next].

   • Select [Route email through these smart hosts].
   • Enter the following FQDN in the text box and click [+].

   gwsmtp.mo.hdems.com

   

7. Set the following values and click [Next].

   • Check [Always use Transport Layer Security (TLS) to secure the connection (recommended)].
   • Select [Issued by a trusted certificate authority (CA)].
   • Check [Add subject name or subject alternative name (SAN) that matches this domain name] and enter the following.

   gwsmtp.mo.hdems.com

   

8. Enter an email address, click the [Add] button [+], then click [Validate].
   * Please enter an email address used within your organization.
   * Validation may take some time to complete.

9. Once validation is successful, click [Next].
   * If validation does not complete successfully and the issue cannot be resolved, please contact your HENNGE representative.

   

10. Review the settings and click [Create connector].

    

    * The following steps should be performed if you want all users in your organization to send emails via Email DLP.
    If you want to filter only emails sent by specific users through Email DLP, please refer to the following article.
    Email DLP: Route Only Specific Senders' Emails via Email DLP (Microsoft 365)

11. Go to [Mail flow] - [Rules], then click [Add a rule] - [Create a new rule].

    

12. Set the following values.

    • [Name]: Rule for HENNGE Email DLP
    • [Apply this rule if] - [The sender] - [is internal/external] - [Select sender location] - Select [Inside the organization], then click [Save].
    • Click the [Add] button [+] for [Apply this rule if], then select [and] - [The recipient] - [is internal/external] - [Select recipient location] - Select [Outside the organization], then click [Save].

    

    • [Do the following] - [Redirect the message to] - [The following connector] - [Select connector] - Select [Email DLP], then click [Save].

    

    • [Except if] - [A message header...] - [includes any of these words], then enter the following in [Enter text] - [Specify header name], and click [Save].

    From

    • In [Enter words] - [Specify words or phrases], enter the following, click [Add], check the checkbox, then click [Save].

    noreply@mo.hdems.com

    

    • Click the [Add] button [+] for [Except if], then select [or] - [Message properties] - [Includes message type] - [Select message type] - Select [Read receipt], then click [Save].

    

    • Click the [Add] button [+] for [Except if], then select [or] - [The sender] - [Domain is] - [Specify domain], and enter the following.

    onmicrosoft.com

    • Click [Add], check the checkbox, then click [Save].

    

13. After configuring the above rule, click [Next].

    

14. Select the following items and click [Next].

    • [Rule mode]: "Apply"
    • [Priority]: "Not specified"
    • [Match sender address in message]: "Header or envelope"

    

15. Review the settings and click [Finish].

16. After confirming the message "The transport rule was created successfully," click [Done].

    

17. In the rule list, check [Rule for HENNGE Email DLP], then select [Move up] or [Move down] at the top to change the priority as needed.

    

18. Select [Rule for Email DLP], click [Enable or disable rule], and set it to [Enabled].

    

19. Check whether the connection has been completed successfully.
    Email DLP Operation Test (Microsoft 365)
20. Notify your HENNGE One implementation representative that the connection has been completed.
    After confirming that the connection is successful, be sure to contact your HENNGE One implementation representative.