How do DMARC quarantine and reject policies affect sender reputation and email delivery?

Key findings

• Policy enforcement: DMARC is primarily a policy mechanism, not a spam filter. It instructs receiving mail servers on how to handle emails that fail SPF or DKIM authentication for your domain.
• Quarantine impact: A quarantine policy typically directs unauthenticated emails to the recipient's junk or spam folder. While it doesn't directly damage sender reputation in the same way a spam complaint does, consistently landing in the spam folder can still affect future inbox placement.
• Reject impact: A reject policy completely blocks unauthenticated emails, meaning they will not be delivered to the recipient's inbox or spam folder at all.
• Receiver discretion: Recipient mail servers interpret DMARC policies as suggestions. Some may choose to treat a reject policy as quarantine, or even accept emails that fail DMARC, depending on their internal filtering rules and trust signals. For more information, explore how DMARC affects email marketing.

Key considerations

• Gradual implementation: It's recommended to gradually roll out DMARC policies, starting with p=none (monitoring), then p=quarantine, and finally p=reject, to avoid blocking legitimate email traffic.
• Monitoring reports: DMARC aggregate reports are essential for identifying legitimate sending sources that might be failing authentication and need to be properly configured before moving to stricter policies.
• False positives: Legitimate emails can fail DMARC for various reasons, such as forwarding services breaking authentication. A reject policy will prevent these from being delivered, leading to lost mail.
• Sender reputation separation: DMARC policy enforcement itself doesn't directly chip away at your sender reputation like spam complaints. Instead, DMARC ensures that only authenticated mail, which contributes to your positive reputation, reaches the inbox.

Key opinions

• Quarantine vs. spam reports: A message placed in the junk folder due to DMARC policy is generally not seen as harming reputation in the same way as a recipient marking an email as spam.
• Authentication priority: If legitimate emails are being quarantined by DMARC, it signals that underlying authentication issues (SPF/DKIM) need to be fixed before enforcing stricter policies.
• The 100% inboxing fallacy: Marketers frequently express frustration with clients who demand 100% inboxing while simultaneously implementing a p=reject policy, acknowledging that some legitimate mail loss is inevitable.
• Policy as a suggestion: DMARC policies are viewed as suggestions; recipient servers might accept emails that fail authentication even with a reject policy, or quarantine them.
• Incremental adoption: Moving from p=none to p=quarantine is often considered a cautious and worthy intermediate step for brand protection and identifying issues.

Key considerations

• Pre-enforcement fixes: Thoroughly address all authentication issues for legitimate email streams before progressing from p=none to p=quarantine or p=reject. Learn why changing to quarantine might send emails to spam.
• Monitoring reports for bounces: If using a quarantine policy, you won't receive bounces for legitimate mail that fails DMARC, making report monitoring critical. A reject policy, conversely, may generate bounces.
• Managing expectations: Recognize that 100% inboxing is rarely achievable, particularly with strict DMARC enforcement, due to factors like forwarding breaking authentication.
• Impact on revenue: Without a DMARC policy, senders risk higher email rejection rates, which can significantly impact revenue. Understanding how DMARC works is crucial.
• Reputation alignment: DMARC helps protect your domain's reputation by ensuring that receiving servers can confidently determine the authenticity of your emails and act upon unauthenticated ones, thereby mitigating the impact of phishing and spoofing on your brand. For further reading, see how DMARC, spam complaints, and IP reputation affect deliverability.

Key opinions

• DMARC's role: Experts emphasize that DMARC is a policy mechanism for unauthenticated mail, not a spam filter. It allows for graduated deployment using policies like quarantine and reject.
• Receiver behavior: Despite a sender's DMARC policy, recipient servers may act differently, for example, treating a reject policy as quarantine or even accepting non-compliant mail.
• Data-driven decisions: DMARC reports are essential for monitoring legitimate emails that fail authentication, as these failures won't necessarily result in bounces, especially with a quarantine policy.
• False positives risk: Experts advise against strict DMARC enforcement if the projected false positive rate (legitimate emails failing) is too high, as it leads to lost mail.
• Reputation effect: Mail failing DMARC is considered unauthenticated, and thus its delivery does not impact the sender's domain reputation. DMARC ensures that only authenticated mail, which contributes positively, is delivered.

Key considerations

• Phased transition: Adopt a phased approach, typically p=none to p=quarantine to p=reject, to cautiously identify and resolve authentication issues without losing legitimate mail.
• Forwarding challenges: Be aware that email forwarding services can break SPF and DKIM authentication, causing legitimate emails to fail DMARC and potentially be rejected or quarantined.
• Continuous monitoring: Rely on DMARC aggregate and forensic reports to gain visibility into email streams and troubleshoot authentication problems. For more information, see understanding and troubleshooting DMARC reports.
• Authentication foundation: Ensure robust SPF and DKIM configurations for all legitimate sending sources to minimize DMARC failures.
• Brand protection: DMARC significantly reduces phishing and spoofing attacks that impersonate your domain, thereby protecting your brand's reputation, as highlighted by Word to the Wise.

Key findings

• Protocol definition: DMARC is an email authentication protocol that leverages SPF and DKIM to protect domains from fraudulent use, such as phishing and spoofing.
• Policy options: DMARC defines three policies: p=none (monitoring), p=quarantine (send to spam), and p=reject (block delivery).
• Reporting capability: DMARC includes reporting mechanisms (RUA for aggregate reports, RUF for forensic reports) to provide domain owners with visibility into their email ecosystem and authentication results.
• Gradual rollout recommended: Official guidance encourages starting with p=none to gather data and identify all legitimate sending sources before moving to enforcement policies.
• Brand reputation: Implementing the right DMARC policy can stop email impersonation and protect brand reputation, as detailed by Sendmarc.

Key considerations

• Alignment requirement: For DMARC policy to be enforced, email must pass both SPF and DKIM authentication, and the domain in the From header must align with the SPF or DKIM domains. Understand how DMARC, SPF, and DKIM work together.
• Policy interpretation: While DMARC provides explicit instructions, recipient mail servers ultimately retain the discretion to interpret and apply these policies based on their own filtering logic.
• Continuous monitoring: It is essential to continuously monitor DMARC reports to ensure that legitimate email is not adversely affected by the enforcement policy and to identify any unauthorized senders.
• Tag usage: The DMARC record includes various tags that define the policy, reporting addresses, and other settings. Familiarize yourself with a list of DMARC tags and their meanings.
• Policy enforcement details: Official documentation often delves into the reasons why email may fail DMARC policy evaluation, providing insights into proper configuration and troubleshooting, as discussed by Amazon Web Services.