Target
- Customers using Email DLP with Microsoft 365
Purpose
- This explains how to route emails sent from Microsoft 365 (Exchange Online) to outside the organization through Email DLP.
Notes
- After this connection work, the outboud route will change. Therefore, please carefully consider the impact range and work time before proceeding.
- The content of this article is based on the product as of May 2025 and may change without notice thereafter.
- SPF record registration is required before this connection work.
[Email DLP] Add SPF Record - If there are already settings in the following parts, please send a screenshot showing the settings to us before this connection work to confirm the impact on the email route.
・[Exchange Admin Center] Left menu [Mail Flow] - [Rules]
・[Exchange Admin Center] Left menu [Mail Flow] - [Connectors]
Procedure
1. Access the Exchange Admin Center.
https://admin.cloud.microsoft/exchange
2. Access [Mail Flow] - [Connectors] and click [+ Add a 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 I have a transport rule set up that redirects messages to this connector] and click [Next].
6. Set the following values and click [Next].
- [Route email through these smart hosts]: Select
- Text box: Enter the following FQDN and click [+]
gwsmtp.mo.hdems.com
7. Set the following values and click [Next].
- [Always use Transport Layer Security (TLS) to secure the connection (recommended)]: Check
- [Issued by a trusted certificate authority (CA)]: Select
- [Add subject name or subject alternative name (SAN) that matches this domain name]: Check and enter the following
gwsmtp.mo.hdems.com
8. Enter the email address, click the add button [+], and then click the [Validate] button.
※ Please enter an email address used within your company.
※ Validation may take some time to complete.
9. Once validation is successful, click [Next].
※ If validation does not complete successfully and the issue is not resolved, please contact us.
10. Review the settings and click [Create connector].
※ The following steps are performed when routing all emails sent by users within the organization through 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 Sender's Emails through Email DLP (Microsoft 365)
11. Access [Mail Flow] - [Rules] and select [Add a rule] - [Create a new rule].
12. Set the following values.
- Name: Rule for HENNGE Email DLP
- [Apply this rule] - [The sender] - [Is external/internal] - [Select sender location] - Select [Inside the organization] and click [Save]
- Click the add button [+] for [Apply this rule] and select [And] - [The recipient] - [Is external/internal] - [Select recipient location] - Select [Outside the organization] and click [Save]
- [Do the following] - [Redirect the message to] - [The following connector] - [Select connector] - Select [HENNGE Email DLP] and click [Save]
- [Except if] - [The message headers...] - Select [includes any of these words], 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, and click [Save]
noreply@mo.hdems.com
- Click the add button [+] for [Except if], select [Or] - [The message properties] - [Includes message type] - [Select message type] - Select [Read receipt] and click [Save]
- Click the add button [+] for [Except if], select [Or] - [The sender] - [Domain is] - Enter the following in [Specify domain]
onmicrosoft.com
- Click [Add], check the checkbox, and click [Save]
13. After setting the above rules, click [Next].
14. Select the following items and click [Next].
- Rule mode: Enforce
- Severity: Not specified
- Matches sender address in message: Header or envelope
15. Review the settings and click [Finish].
16. Confirm the display of [Transport rule was successfully created] and click [Done].
17. In the rule list, check [Rule for HENNGE Email DLP], select [Move up] or [Move down] at the top, and change the priority as desired.
18. Select [Rule for HENNGE Email DLP], click [Enable or disable rule], and set it to [Enabled].
19. Confirm whether the connection is successfully completed.
[Email DLP] Operation Test (Microsoft 365)
20. Notify the HENNGE One implementation representative that the connection is completed.
Ensure the connection is successfully completed and be sure to contact the HENNGE One onboarding guide.