[Email DLP] Add new domain to existing DKIM

Overview

This article explains how to apply DKIM to a new Domain for customers who have already configured DKIM in Email DLP and wish to add a new Domain.
※ To add a Domain, please refer to the following article.
What are the procedures to add additional domain? 

Notes

1. The content of this article is based on product specifications as of October 2026 and may be changed without prior notice.
2. An Administrator Role for Email DLP is required to view the screens and change settings.
   For instructions on accessing the management console, please refer to the following article.
   Accessing Method to Email DLP Management Console 
3. To enable DKIM records for multiple Domains, including subdomains (E.g., sub.example.com), add TXT records to the DNS for all Target Domains.
   ※ You can also reference the TXT record registered for the main Domain using a CNAME record.
   For Details, please refer to the following article.
   [Email DLP] If using multiple domains, is it necessary to register the DKIM public key for all domains? 

Procedure

1. In the Email DLP management console, select ［Tenant Settings］－［DKIM］, then click the ［Setup］ link.
   ※ If DKIM is Not configured, please refer to the following article.
   [Email DLP] Tenant Settings - DKIM Settings

   

2. Add the displayed value to the TXT record in the DNS of the Domain you wish to Add.
   You can copy the TXT record name and TXT record value by clicking the copy button displayed to the right of the TXT record name and TXT record value.
   ※ By Default, the TXT record value includes the "t=y;" (Test Mode) tag. Clear the checkbox for ［Include the Test Mode tag (t=y;)］ before copying.
   ※ To enable DKIM signing for multiple Domains, including subdomains (E.g., sub.example.com), you must Add this TXT record to the DNS of each Target Domain.

   

3. Open Command Prompt (Windows) or Terminal (Mac OS), run the command, and Confirm that the configured TXT record value is displayed.

   For Windows OS ※ Run this command in Command Prompt.

   nslookup -type=TXT <セレクタ名>._domainkey.<追加ドメイン> 8.8.8.8

   【View example】

   C:\Windows\system32>nslookup -type=TXT <セレクタ名>._domainkey.<追加ドメイン> 8.8.8.8
   サーバー: dns.google
   Address: 8.8.8.8
   
   権限のない回答:
   <セレクタ名>._domainkey.<追加ドメイン>. text =
   "v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3<中略>dPx4QIDAQAB"

   For Mac OS ※ Run this command in Terminal.

   dig +short @8.8.8.8 <セレクタ名>._domainkey.<追加ドメイン> txt

   【View example】

   dig +short @8.8.8.8 <セレクタ名>._domainkey.<追加ドメイン> txt
   "v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3<中略>dPx4QIDAQAB"

4. After the TXT record registration is Completed, return to ［Tenant Settings］－［DKIM］ Setup in the Email DLP management console, then click ［Setup］ for the selector In Use. 

   

5. Enter the new Domains, separating each one with a line break. 

   

6. Click the ［Apply］ button.

Translation Disclaimer

This article has been automatically translated from the original Japanese version for your convenience.
While we strive to ensure accuracy, we cannot guarantee its reliability or completeness.

In the event of any discrepancies or questions regarding the content, the official Japanese version shall prevail.