[Email DLP] Filter Settings - Forced Conversion Settings for External Email Addresses

Action summary

This article explains how to configure the Automatic Address Pruning Settings feature, which removes addresses from the header if the number of addresses other than those in the specified excluded domains exceeds the address threshold when sending emails.

The Automatic Address Pruning Settings feature is a misdelivery prevention function that automatically removes recipients and email addresses other than those in the excluded domains from the To and CC headers if external email addresses not in the pre-configured excluded domains are present in the recipients.

This feature is mainly used when sending emails to a large number of unspecified recipients, such as newsletters or notifications, to prevent accidental disclosure of email address information by mistakenly specifying recipients in the To or CC fields.

Notes

1. The content of this article is based on the product specifications as of April 2026 and is subject to change without notice.
2. This feature is configured for the entire tenant.
   Therefore, it cannot be applied only to specific Email DLP rules.
3. To view the actual screen or modify the settings, Email DLP admin privileges are required.
   For instructions on how to configure admin privileges, please refer to the following article.
   [Email DLP] How to configure admin privileges
4. For instructions on how to access the Administration, please refer to the following article.
   [Email DLP] How to log in to the Administration

Procedure

1. From the left menu of the Email DLP Administration, go to Filter Settings > Automatic Address Pruning Settings.

   

2. Set the status to Enabled, enter the desired address threshold and excluded domains, then click Save Changes.

   

   Address threshold: The process will be executed when the number of addresses other than those in the excluded domains meets or exceeds this value.
   * You can enter a number from 2 to 1000.

   Excluded domains: Specify the domains that should not be counted toward the address threshold.
   * If you need to exclude domains that have already been registered as HENNGE usage domains, please also specify them here as excluded domains.
   * At least one domain must be entered.
   * To enter multiple excluded domains, enter each domain on a separate line.
   * You can register up to 1000 excluded domains.