Summary
The question of which DMARC settings to use, particularly whether to maintain a p=reject policy or revert to p=none in light of recent sender requirements, often arises among email marketers. The consensus among experts is clear: if you are already at p=reject with pct=100, you meet or exceed the requirements of mailbox providers like Google and Yahoo, and there is no need to roll back. p=reject is the strongest enforcement policy, offering maximum protection against email spoofing and phishing.
Key findings
- No rollback needed: If your DMARC policy is already set to p=reject (and pct=100), you do not need to downgrade to p=none to comply with new sender requirements.
- Strongest protection: The p=reject policy is the most robust DMARC setting, instructing receiving servers to block emails that fail authentication, thus enhancing security and trust. You can learn more about use cases for DMARC policies.
- Aggregate reports are crucial: Regardless of your policy, implementing a rua tag for aggregate reports is highly recommended to monitor email authentication status and identify potential issues.
- Phased implementation: While not applicable if already at p=reject, the general best practice for moving to an enforced DMARC policy is a gradual transition, often starting with p=none and progressing to p=quarantine or p=reject.
Key considerations
- DMARC alignment: Ensure your legitimate email sending sources are properly configured for SPF and DKIM alignment before moving to (or maintaining) a p=reject policy. This prevents legitimate emails from being blocked. Discover more about key considerations for DMARC implementation.
- Reporting is critical: Operating with p=reject without receiving aggregate DMARC reports (via rua tag) is considered risky. These reports provide visibility into your email ecosystem, helping identify misconfigurations or unauthorized sending.
- Understanding implications: While p=reject offers strong protection, a misconfigured policy can lead to legitimate emails being blocked or blacklisted, impacting your email deliverability. This is why implementing DMARC safely is paramount.
- ISP expectations: Major mailbox providers, such as Gmail and Yahoo, require an enforced DMARC policy (at least p=quarantine or p=reject) for bulk senders to ensure trust and combat spam. A p=reject policy already fulfills this requirement. For more information, see Understanding DMARC policies.
What email marketers say
Email marketers frequently discuss DMARC policy settings, particularly in the context of new email provider requirements. Many are concerned about whether their existing p=reject policies are still appropriate or if they need to revert to less stringent settings. The general sentiment is that p=reject is a strong, desirable state for DMARC, provided it's correctly implemented and monitored.
Key opinions
- No downgrade needed: Marketers generally agree that if a domain is already enforcing DMARC at p=reject, there is no requirement to revert to a p=none policy as it already surpasses the minimum requirements.
- Stronger policy: Many marketers view p=reject as the ideal and most protective DMARC policy, offering superior defense against domain abuse. See why a strong DMARC policy is crucial.
- Importance of reporting: Marketers frequently highlight the need for DMARC aggregate reports, emphasizing that a p=reject policy without monitoring can lead to unseen deliverability issues.
- Removing redundancies: The pct=100 tag is often considered superfluous in a DMARC record, as it represents the default behavior.
Key considerations
- Avoiding accidental blocking: Ensure all legitimate email flows are properly authenticated with SPF and DKIM and aligned with DMARC. Failure to do so with p=reject can result in emails being blocked. Learn how to implement DMARC safely.
- Continuous monitoring: Maintaining a p=reject policy requires ongoing monitoring of DMARC reports to detect and resolve any authentication failures for legitimate mail.
- ESP guidance: While some ESPs might provide generic advice, marketers should understand that p=reject is generally acceptable and often preferred over p=none.
- Policy progression: For those not yet at p=reject, a strategic move from p=none to p=quarantine and then p=reject is often advised to prevent deliverability issues during implementation. For further reading, check Switching to Reject: All About DMARC Policy.
Marketer view
Marketer from Email Geeks questioned if their existing DMARC record, set to v=DMARC1; p=reject; pct=100;, would need to be updated to p=none to comply with new mailbox provider suggestions.
Marketer view
Marketer from Email Geeks confirmed that if a domain is already enforcing a DMARC policy, there is no requirement to roll it back to a less strict setting like p=none.
What the experts say
Email deliverability experts consistently advocate for DMARC p=reject as the optimal policy for maximum domain protection against spoofing and phishing. However, they strongly emphasize that moving to, or maintaining, this stringent policy requires meticulous planning, proper authentication setup (SPF, DKIM), and rigorous monitoring through DMARC reports. Blindly implementing p=reject without these safeguards can severely impact legitimate email deliverability, potentially leading to widespread email blockages (sometimes known as being put on a blacklist or blocklist) and significant operational disruptions.
Key opinions
- Reporting is non-negotiable: Experts agree that operating DMARC at p=reject without receiving aggregate reports (e.g., via a rua tag) is a highly risky expert-level maneuver not recommended for most.
- Align before enforcing: The critical step before moving to p=reject is to ensure all legitimate email sources are properly authenticated with SPF and DKIM and achieve DMARC alignment. Otherwise, legitimate mail will be rejected.
- Gradual implementation recommended: A phased approach, starting with p=none and progressing through p=quarantine with continuous monitoring, is the safest path to p=reject.
- Beware of false simplicity: Implementing DMARC to p=reject is not always simple, especially for organizations with complex sending infrastructures. Over-simplifying the process can lead to significant deliverability failures.
Key considerations
- Risk of legitimate email loss: A poorly implemented p=reject policy can cause legitimate emails to be blocked or sent to spam folders, negatively impacting business operations or customer communications. Learn how DMARC policies affect sender reputation.
- Full visibility needed: Before enforcing p=reject, it's essential to have complete visibility into all sending sources for your domain, including third-party senders, to ensure they comply with authentication standards. For information on what DMARC is, consult Fortinet's cyberglossary.
- Parent company influence: Mandating a p=reject policy from a corporate level without providing adequate support, guidance, or reporting access to subsidiaries can lead to significant and unintended deliverability issues.
- Knowledge is key: A superficial understanding of DMARC can be dangerous, as it might lead to incorrect configurations that inadvertently block legitimate emails, stressing the need for expert guidance.
Expert view
Expert from Email Geeks warned that implementing DMARC with a p=reject policy without proper reporting is a highly advanced maneuver not recommended for typical users.
Expert view
Expert from Email Geeks advised humorously that combining a p=reject DMARC policy with a v=spf1 -all SPF record would result in an extremely strict, though potentially problematic, email rejection setup.
What the documentation says
Official documentation from various email security and deliverability providers consistently outlines the purpose and implications of DMARC policies. For p=reject, the documentation emphasizes its role in directing receiving servers to block emails that fail DMARC authentication checks. This policy is presented as the most assertive measure for domain protection, preventing unauthenticated emails (often spoofing or phishing attempts) from reaching recipients at all. It is universally implied that implementing p=reject should only occur after a thorough understanding of all legitimate email sources and careful monitoring of DMARC reports.
Key findings
- Direct blocking instruction: Documentation confirms that p=reject instructs receiving mail servers to outright block any incoming emails that fail DMARC authentication for your domain.
- Highest enforcement level: This policy provides the strongest level of DMARC enforcement, ensuring that unauthenticated messages are discarded before reaching the inbox or spam folder.
- Anti-spoofing mechanism: Documentation consistently positions p=reject as a primary tool to combat email spoofing and phishing attacks originating from your domain. Read more about how to use DMARC p=reject to combat email spoofing.
- Compliance with major ISPs: Implementing p=reject satisfies the stricter DMARC enforcement requirements set by major email providers for bulk senders.
Key considerations
- Prerequisite for implementation: Documentation typically advises that p=reject should only be adopted after a thorough analysis of DMARC reports to ensure all legitimate sending sources are properly authenticated and aligned.
- Potential for legitimate email loss: Misconfigurations or lack of proper authentication for legitimate mail flows will result in those emails being rejected, leading to deliverability issues. This is a common challenge, and you can learn how to troubleshoot DMARC reject policies.
- Importance of monitoring: Continuous monitoring of DMARC aggregate reports is essential with a p=reject policy to detect any unintended rejections and maintain optimal email deliverability.
- Gradual transition: While not directly applicable if already at p=reject, documentation generally advocates for a careful, incremental approach (e.g., via pct tag) when moving towards a p=reject policy. For more, see the Email Security: Relaxed DMARC vs. Strict DMARC article.
Technical article
Documentation from Sendmarc's DMARC guide specifies that a p=reject policy instructs receiving servers to completely block emails that fail DMARC authentication, preventing their delivery.
Technical article
Documentation from Email on Acid's blog confirms that the p=reject DMARC policy explicitly tells mailbox providers not to accept any messages that fail authentication checks for a given domain.
Related resources
9 resources
Related pages
How to implement DMARC p=reject policy safely to avoid email deliverability issues?
When should you use DMARC p=none, p=quarantine, or p=reject policies?
What are the best practices for setting DMARC policy, particularly p=reject?
How to safely transition your DMARC policy to quarantine or reject
Simple DMARC examples: how to start with a p=none policy
List of DMARC tags and their meanings
How important is DMARC for email and spam protection, and when should it be enabled?
How do I troubleshoot DMARC reject policies and improve email deliverability?
Why might an email provider not honor a DMARC p=reject policy?
Understanding and troubleshooting DMARC reports from Google and Yahoo
