MXToolbox Health Checker reports warning for a domain in Plesk: DMARC Quarantine/Reject policy not enabled

Question

Why MXToolbox Health Checker reports the following warning for a domain in Plesk?

PLESK_INFO: DMARC Quarantine/Reject policy not enabled

Answer

By default, DMARC policy in Plesk is set to "none" (p= option):

CONFIG_TEXT: _dmarc.example.com.        TXT        v=DMARC1; p=none

Quarantine/reject policies can be configured if required. These policies request more aggressive protective actions by receivers and should be configured with care.

Additional Information

According to https://dmarc.org/wiki/FAQ:

PLESK_INFO: It is highly recommended that you start with a DMARC “p=none” record in order to monitor the results before moving on to a quarantine or reject policy. The goal of DMARC, when your policy is “p=reject”, is to get the receiver to reject emails that don’t come from your email infrastructure, not to help them make a decision about whether the email you did send is spam.

However, if your policy is “p=quarantine” and you have configuration issues, your mail will be placed in the spam folder because that is what you are asking for.

With a policy of “p=none”, DMARC does not change in any way how your email is handled at the receiver.

More information about these policies you may read here:

• FAQ: What does a "quarantine" policy mean in a DMARC record? - DMARC Wiki
• FAQ: Does DMARC “p=none” affect the way my emails get delivered? - DMARC Wiki