How should I enforce DMARC policies for a bulk sender with p=none?
Michael Ko
Co-founder & CEO, Suped
Published 24 May 2025
Updated 17 Aug 2025
9 min read
For bulk email senders, navigating DMARC policy enforcement can be a complex but critical task. Many organizations start their DMARC journey with a policy of p=none, a monitoring-only setting. This initial phase is invaluable for gathering data on your email ecosystem without impacting deliverability. However, the ultimate goal is often to transition to a more stringent policy like p=quarantine or p=reject to actively protect your domain from spoofing and phishing.
The challenge arises when DMARC reports, even under a p=none policy, reveal a significant number of emails failing authentication. If you see hundreds of emails being flagged, it's a clear indication that not all legitimate sending sources are properly configured, or that there's substantial unauthorized use of your domain. Moving directly to p=quarantine or p=reject without addressing these issues could lead to legitimate emails being quarantined or rejected, severely impacting your email deliverability and business communications.
My recommendation is always to prioritize identifying and authenticating all your legitimate email sending sources while your DMARC policy is set to p=none. This approach allows you to gather comprehensive data and fix misconfigurations without risking the delivery of your important emails. Once you are confident that all your authorized mail streams are properly aligned with SPF or DKIM, you can then safely proceed to a stricter enforcement policy.
The p=none policy is primarily a monitoring policy, as highlighted by various email security experts. It instructs receiving mail servers not to take any specific action (like quarantining or rejecting) on emails that fail DMARC authentication, but still to send DMARC reports to the domain owner. This allows you to gain visibility into who is sending email on behalf of your domain, whether legitimately or maliciously. For bulk senders, this initial phase is crucial, especially with the new requirements from major mailbox providers such as Google, Yahoo, and Microsoft, which now mandate DMARC implementation with at least a p=none policy. While p=none is a valid starting point, it doesn't offer protection against email spoofing. For comprehensive security, you will eventually want to move beyond it. To learn more about its utility, read my article, Does a DMARC policy of 'none' negatively impact email reputation?.
The purpose of p=none
The p=none policy, also known as the monitoring policy, is foundational for DMARC deployment. It allows you to collect DMARC aggregate (RUA) and forensic (RUF) reports which provide insight into how your domain's emails are being treated by recipient mail servers. This data helps you identify legitimate sending sources that might not yet be authenticated with SPF or DKIM, as well as detect any unauthorized use (spoofing) of your domain. As this article on DMARC policies points out, it is crucial for initial setup and monitoring.
Without this initial monitoring phase, moving straight to a stricter policy could inadvertently block your own legitimate emails, leading to significant deliverability issues. It's a discovery phase that lets you understand your email sending landscape fully before enforcing any actions.
A DMARC record with p=none is typically published as a TXT record in your DNS. Here's a basic example:
This record specifies DMARC version 1, sets the policy to none, and directs aggregate reports to the specified email address. For more examples, see my guide to simple DMARC examples.
The importance of DMARC reporting and data
The core of DMARC enforcement lies in the data you receive through DMARC reports. These reports, particularly the aggregate (RUA) reports, provide a complete picture of all email traffic using your domain, including legitimate mail streams and any unauthorized (spoofing or phishing) attempts. It's not enough to just publish a p=none policy, you must actively analyze the reports to identify and address any issues. This is especially true when dealing with an existing domain that has multiple sending services or shadow IT where departments might be using unauthorized sending services.
Before DMARC report analysis
Limited visibility: Unaware of all legitimate sending sources.
Unknown spoofing: Potential for brand abuse and phishing attacks without detection.
Deliverability risks: Risk of legitimate emails failing authentication when moving to enforcement.
After DMARC report analysis
Full visibility: Identification of all email sending services, including third-party providers.
Spoofing detection: Ability to pinpoint unauthorized senders and take action.
Improved deliverability: Confidence to move to stricter policies knowing all legitimate mail is authenticated.
Regularly reviewing your DMARC reports is essential. It's a continuous process, not a one-time setup. Once you're comfortable that all your legitimate sources are correctly authenticating and aligning (both SPF and DKIM), you can then proceed with confidence to enforce your DMARC policy. You can learn more about this in my guide, Understanding and troubleshooting DMARC reports.
Steps to move to stronger DMARC policies
The transition from p=none to p=quarantine and then to p=reject should be a phased approach. After thoroughly reviewing your DMARC reports under p=none and authenticating all known legitimate sources, you can increase your policy's strictness. Many email professionals suggest monitoring with p=none for at least a month to ensure you capture all sending behaviors. To understand the different policies, read my article, When should you use DMARC p=none, p=quarantine, or p=reject policies?.
The next step is to change your DMARC record to p=quarantine. This instructs recipient mail servers to place unauthenticated emails from your domain into the spam or junk folder. This is a softer enforcement that allows you to observe the impact on mail flow and verify that no legitimate emails are being incorrectly marked as spam before moving to a full reject policy. For detailed steps, consult my guide, How to safely transition your DMARC policy.
Once you're satisfied with the results at p=quarantine (typically after several weeks of monitoring), the final step is to switch to p=reject. This policy instructs receiving mail servers to outright reject emails that fail DMARC authentication. This provides the highest level of protection against email spoofing and phishing for your domain. Implementing p=reject ensures that only emails from authorized senders using your domain reach the inbox. My article, How to implement DMARC p=reject policy safely, offers further guidance.
Addressing common challenges
One common challenge, especially for organizations with multiple email sending purposes (like general business communications, marketing, and transactional emails), is ensuring all legitimate sources are covered. If all your email types are sent from your apex domain (e.g., yourdomain.com) without using subdomains, it complicates DMARC enforcement. A p=reject policy at the apex domain can inadvertently disrupt essential business communications if any legitimate source is not properly authenticated. Mailbox providers like Yahoo provide clear sender best practices that emphasize strong authentication.
Consider the use of subdomains. It is often beneficial to send different types of email from distinct subdomains. For instance, marketing.yourdomain.com for marketing campaigns and transactions.yourdomain.com for transactional emails. This allows you to apply different DMARC policies to each subdomain if needed, providing more granular control and reducing risk. For example, your transactional subdomain might go to p=reject quickly, while your marketing subdomain (or apex domain for general communications) might remain at p=quarantine longer as you fine-tune its authentication.
Email type
Recommended DMARC approach
Why it works
General business communications
Apex domain (yourdomain.com) with cautious enforcement.
Minimizes disruption to day-to-day operations and allows monitoring of varied sending behaviors.
Marketing emails
Dedicated subdomain (e.g., m.yourdomain.com) with progressive enforcement.
Isolates marketing reputation and allows for more aggressive DMARC policies without affecting other mail streams.
Transactional emails
Dedicated subdomain (e.g., t.yourdomain.com) with swift enforcement to p=reject.
Ensures critical emails are authenticated and delivered reliably, minimizing the risk of spoofing.
Finally, even with a strong DMARC policy, continuous monitoring of your DMARC reports is essential. Your email sending environment can change, new services might be adopted, or configurations might be inadvertently altered. Regular review ensures ongoing compliance and protection. If you need help with DMARC implementation, a list of DMARC vendors and solutions can be a valuable resource.
Views from the trenches
Best practices
Authenticate all legitimate email sources including third-party senders.
Use DMARC reports (RUA and RUF) to identify all sending patterns.
Segment email types using subdomains for more controlled DMARC enforcement.
Implement a phased DMARC rollout, gradually moving from p=none to p=quarantine and p=reject.
Common pitfalls
Moving to p=quarantine or p=reject too quickly without sufficient monitoring.
Not authenticating all legitimate email sources, leading to legitimate email being blocked.
Overlooking 'shadow IT' where departments use unapproved email services.
Treating the apex domain and subdomains with the same DMARC policy without consideration.
Expert tips
Ensure that any 'illegitimate' source showing significant volume is investigated, as it could be a legitimate but unauthenticated sender (shadow IT).
DMARC p=quarantine and p=reject policies are very similar in their effect: unauthenticated mail will likely not be delivered.
Monitor DMARC reports at p=none for at least a month to thoroughly understand email flow before enforcing stricter policies.
For a domain with multiple uses, separate marketing and transactional email sending to subdomains for dedicated DMARC policies.
Expert view
Expert from Email Geeks says authenticate all legitimate sources and then enforce policies.
June 11, 2024 - Email Geeks
Expert view
Expert from Email Geeks says to check any illegitimate sources that have a noticeable volume, as they might be unauthenticated legitimate senders, especially for domains with multiple uses.
June 11, 2024 - Email Geeks
Summary
For bulk senders currently operating with a DMARC p=none policy, the path to stronger enforcement is clear yet requires careful execution. The initial phase of monitoring is invaluable for understanding your email ecosystem and identifying all legitimate sending sources, including any 'shadow IT' operations. By leveraging the data from DMARC reports, you can ensure that all authorized email streams are properly authenticated with SPF and DKIM, and that they achieve DMARC alignment.
Once you have a clear picture and have addressed any authentication failures for your legitimate mail, you can begin the phased transition to p=quarantine and then to p=reject. This gradual approach minimizes the risk of inadvertently blocking your own emails and ensures a smooth transition to full DMARC enforcement. For more information about DMARC, SPF, and DKIM, check out my simple guide, A simple guide to DMARC, SPF, and DKIM.
By following these steps, bulk senders can enhance their email security, protect their brand from impersonation, and improve email deliverability, ensuring their messages consistently reach the intended recipients' inboxes rather than being sent to the junk folder or blocked outright. Best practices for p=reject are detailed in my article, What are the best practices for setting DMARC policy?.
Google, 
Yahoo, and 
Microsoft, which now mandate DMARC implementation with at least a p=none policy. While p=none is a valid starting point, it doesn't offer protection against email spoofing. For comprehensive security, you will eventually want to move beyond it. To learn more about its utility, read my article, Does a DMARC policy of 'none' negatively impact email reputation?.
Yahoo provide clear sender best practices that emphasize strong authentication.
