When you're setting up DMARC for the first time, you'll encounter a critical setting: the policy tag, represented by p=. This tag tells receiving mail servers what to do with emails that claim to be from your domain but fail authentication checks. There are three options: none, quarantine, and reject.
The p=none policy, often called the 'monitoring policy', is the most passive of the three. It essentially tells servers to take no action against failing emails. While that might sound ineffective, it serves a very specific and vital purpose in the DMARC implementation process.
What p=none actually does
A DMARC policy of p=none instructs mailbox providers not to reject or quarantine messages that fail DMARC authentication. The email will be delivered to the recipient’s inbox as if DMARC wasn't there. So, what's the point? The real value of p=none lies in its reporting capability.
Even with this policy, receiving servers will collect data about emails sent from your domain and send DMARC aggregate (RUA) reports back to the address you specify in your DMARC record. As Mailjet explains, the policy tells the receiver to do nothing with a failing message but to send a report about it. These reports are XML files that provide a comprehensive overview of your email traffic, including which IPs are sending mail on your behalf and their authentication status.
The role of p=none in a DMARC implementation
You should always start a DMARC implementation with p=none. Moving directly to a quarantine or reject policy without knowing all your legitimate sending sources is risky; you could inadvertently block important emails. The monitoring phase allows you to safely gather intelligence.
- Identify all your legitimate sending services, including third-party providers like marketing platforms and payroll systems.
- Find any misconfigurations in your SPF or DKIM records for those legitimate services.
- Discover if anyone is using your domain for spoofing or phishing attacks.
- Verify that your emails are achieving DMARC alignment.
This phased approach is a widely accepted best practice. As Mailgun suggests, your strategy should evolve gradually, like a traffic light, starting from p=none.
The risks of staying on p=none
While p=none is a crucial starting point, it should never be your final destination. A p=none policy provides zero protection against email spoofing. Attackers can still send emails using your domain, and those fraudulent messages will be delivered. You will get reports about it, but the damage will have already been done.
Staying on a monitoring policy indefinitely leaves your domain vulnerable. It's like having a security camera that records a break-in but doesn't have an alarm to stop it. Furthermore, major mailbox providers like Google and Yahoo now require bulk senders to have a DMARC policy of at least p=quarantine, meaning p=none is no longer sufficient for maintaining good deliverability with them.
Moving beyond monitoring
Once you have analyzed the reports from your p=none phase and are confident that all your legitimate mail is authenticating correctly, it's time to move to an enforcement policy.
p=quarantine: This policy tells receiving servers to treat failing emails as suspicious and place them in the recipient's spam or junk folder.
p=reject: This is the most secure policy. It instructs servers to block and reject any email that fails DMARC checks, preventing it from ever reaching the recipient.
In summary, a DMARC p=none policy signifies the start of your email authentication journey. It's an indispensable tool for gaining visibility into your email ecosystem without risk. However, it offers no actual protection and should be seen as a temporary phase before progressing to quarantine and, ultimately, reject to fully secure your domain against spoofing and improve your email deliverability.
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Can DMARC policies be applied without an SPF or DKIM record?
What DMARC policy allows for email delivery but marks suspicious emails?
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