Question
I followed the instructions in the [Email DLP] Publishing DMARC Records article to configure and publish DMARC. How should I subsequently strengthen the DMARC security Policy from the 「p=none」 （take no action） setting?
Answer
When the 「p=none」 （take no action） setting is registered in a DMARC Record, DMARC-compatible receiving mail servers will perform DMARC verification. However, in general, the verification result will not affect whether emails are received.
Therefore, while 「p=none」 can reduce the likelihood of email rejection caused by DMARC verification, it is less effective in strengthening email security.
To strengthen email security, please consider gradually changing the setting from 「p=none」 （take no action） to the following values.
- 「p=quarantine」 （quarantine / isolation）
- 「p=reject」 （reject）
When changing the 「p」 tag in the DMARC Record as described above, we recommend that you: ① configure the email address for receiving DMARC reports in the 「rua」 tag in advance; and ② review reports sent by DMARC-compatible receiving mail servers, such as Microsoft and Google, to carefully assess the email authentication （SPF/DKIM） status of emails sent from your organization.
You can also use the pct tag to adjust the percentage (%) of sent email to which the DMARC Policy is applied from 「1 ~ 100」.
When changing the value of the 「p」 tag to a more restrictive setting, we recommend using the 「pct」 tag to first configure the DMARC Policy to Apply to a small percentage of email. If there are no issues, such as email rejection, gradually increase the percentage of email to which the Policy is applied.
※Please note that raising the DMARC Policy before completing email authentication （SPF/DKIM） implementation may result in email rejection.
By using Domain Protection, you can efficiently analyze DMARC reports and carefully assess the email authentication （SPF/DKIM） status of emails sent from your organization.
[Domain Protection] Service Overview
For information on how to Start using the service, please refer to the following article.
[Domain Protection] List of Setup Procedures
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