Summary
DMARC failure reports, despite proper email authentication, often result from a combination of factors. The most prominent cause is email forwarding, which invalidates SPF as the forwarding server isn't authorized to send on behalf of the original domain. Other contributing factors include misconfigured SPF records, failing DKIM signatures (often due to DKIM key rotation issues), and alignment problems between the 'From:' domain and the domains used for SPF/DKIM. Furthermore, issues with hosted ESP configurations, incomplete DNS propagation, and stringent regional email provider rules can also trigger DMARC failures. Finally, recipient mail server policy settings, even when basic SPF/DKIM passes, can cause a DMARC failure if strict alignment is expected. Thorough auditing of sending sources, ensuring proper SPF/DKIM alignment, regularly checking DKIM signatures, and understanding recipient policy requirements are essential to address these issues.
Key findings
- Forwarding: Email forwarding remains the primary culprit, as it breaks SPF by using an unauthorized sending server.
- Alignment Problems: Misalignment between the 'From:' domain and SPF/DKIM domains is a key source of DMARC failure.
- Configuration Errors: Misconfigured SPF records or failing DKIM signatures (including key rotation problems) contribute significantly.
- Infrastructure Issues: Hosted ESP configurations with shared IPs and varying practices, along with DNS propagation delays, can trigger failures.
- Policy Enforcement: Recipient server policies (strict vs. relaxed) and regional email regulations impact DMARC compliance.
Key considerations
- Audit Sending Sources: Regularly audit all email sending sources to ensure accurate SPF/DKIM configuration.
- Ensure Alignment: Verify that SPF and DKIM domains align correctly with the 'From:' domain.
- Check DKIM: Regularly verify that DKIM signatures are valid, and keys are correctly rotated.
- Review Policy: Review and adapt DMARC policy based on recipient requirements (strict vs. relaxed).
- Monitor DNS: Utilize online tools to check DNS record propagation and ensure consistency.
- Address Forwarding: Find ways to properly handle or avoid forwarding that breaks SPF, perhaps with authenticated forwarding mechanisms.
What email marketers say
10 marketer opinions
DMARC failures, despite seemingly correct email authentication (SPF and DKIM), often stem from forwarding, which invalidates SPF by changing the sending server. Other causes include SPF and DKIM alignment issues, DKIM key rotation problems, multiple sending sources without proper configuration, incorrect DNS settings, hosted ESP configurations with shared IP addresses, non-propagated DNS records, and stricter regional email provider rules. Thorough auditing of sending sources, ensuring proper SPF/DKIM alignment, and reviewing DMARC policies are recommended.
Key opinions
- Forwarding: Email forwarding is a primary cause of DMARC failures because it alters the sending server, invalidating SPF.
- Alignment Issues: DMARC failures occur when the 'Return-Path' domain (for SPF) or the DKIM signature domain doesn't align with the 'From' domain.
- ESP Configuration: Hosted ESP configurations with shared IP addresses and varying authentication practices can trigger DMARC failures.
- DNS Propagation: Incomplete DNS record propagation can lead to DMARC failures despite correct configurations.
- Regional Rules: Stricter email authentication rules from regional providers (e.g., in Europe or Asia) can cause DMARC failures.
- Multiple Sending Sources: Using multiple email sending sources without proper SPF/DKIM configuration for each source can lead to DMARC failures.
Key considerations
- Audit Sending Sources: Regularly audit all email sending sources and ensure they are properly configured with SPF and DKIM.
- Ensure SPF/DKIM Alignment: Verify that SPF and DKIM are properly aligned with the 'From' domain to ensure DMARC compliance.
- Review DMARC Policy: Periodically review your DMARC policy and authentication configurations to align with recipient server requirements.
- Check DNS Records: Use online DMARC checkers to verify that DNS records are properly propagated across multiple locations.
- Hosted ESP: Ensure your ESP properly supports DMARC and consider dedicated IP options.
- Regional Compliance: Research and comply with specific regional email authentication requirements.
- DKIM Keys: Monitor and properly rotate DKIM keys to prevent authentication failures.
Marketer view
Email marketer from Email Geeks explains that the DMARC failure report may be a typical case of forwarding and if the email originated from the MS IP, it can be ignored.
22 Nov 2024 - Email Geeks
Marketer view
Email marketer from ReturnPath shares that issues with hosted ESP configurations can trigger DMARC failures. This is often due to shared IP addresses and varying authentication practices among different senders on the same platform. They suggest ensuring your ESP properly supports DMARC and offers dedicated IP options.
14 Aug 2022 - ReturnPath
What the experts say
4 expert opinions
DMARC failure reports, even with seemingly correct email authentication, can arise from several issues. These include outdated or misconfigured SPF records, failing DKIM signatures, and, most commonly, email forwarding. Forwarding breaks SPF because the forwarder is not authorized to send mail on behalf of the original domain. Ensuring correct SPF and DKIM configuration, particularly signing with the same domain as the 'From:' address, is crucial. Addressing forwarding issues or ensuring authorized forwarding setups are also key to resolving these failures.
Key opinions
- Outdated SPF Records: Outdated or incorrect SPF records can lead to DMARC failures.
- DKIM Signature Failures: Failing DKIM signatures contribute to DMARC failure reports.
- Email Forwarding: Email forwarding is a common cause; it invalidates SPF because the forwarder isn't authorized.
- Domain Alignment: DKIM signatures must align with the 'From:' address domain to pass DMARC checks.
Key considerations
- Review SPF Records: Regularly review and update SPF records to ensure accuracy.
- Check DKIM Signatures: Verify that DKIM signatures are valid and correctly configured.
- Handle Forwarding: Address forwarding issues by authorizing forwarders or advising recipients not to forward emails.
- Domain Alignment: Ensure the DKIM signing domain matches the domain in the 'From:' address.
Expert view
Expert from Word to the Wise shares that if you are seeing DMARC failures and your mail is forwarded, the issue is that forwarding changes the source IP address and breaks SPF. They also share that with DKIM, it's important to sign with the same domain as your From: address.
11 Sep 2021 - Word to the Wise
Expert view
Expert from Email Geeks explains the user should delete the old SPF record and that the TXT record for email.kiusys.com is a broken DKIM entry, and provides the format it should look like.
22 Jul 2022 - Email Geeks
What the documentation says
4 technical articles
DMARC failure reports, despite seemingly correct email authentication, often point to discrepancies between the sender's claimed identity and the actual sending source. This can be due to forwarding, misconfigurations, or misaligned identifiers, where the domain in the 'From' header doesn't match the domains used for SPF or DKIM authentication. Issues can also arise from policy settings on the recipient's mail server. Reviewing message headers and ensuring consistent domain alignment are crucial for troubleshooting.
Key findings
- Discrepancies in Identity: DMARC reports highlight discrepancies between the sender's claimed identity and the actual sending source.
- Misaligned Identifiers: A primary cause is misaligned identifiers, where the 'From' domain doesn't match SPF or DKIM domains.
- Configuration Issues: Misconfigured SPF records, DKIM signature issues, or non-compliant relay servers lead to failures.
- Recipient Policy Settings: Recipient mail server policies can trigger failure reports, even with passing SPF/DKIM, if requirements aren't fully met.
Key considerations
- Review Message Headers: Check the message header for detailed authentication results to pinpoint the failure's cause.
- Ensure Domain Alignment: Maintain consistent domain alignment between the 'From' header and SPF/DKIM authentication.
- Address Forwarding: Be mindful of email forwarding and its impact on SPF validation.
- Adjust DMARC Policy: Consider adjusting your DMARC policy to meet common recipient server requirements.
Technical article
Documentation from Google Workspace Admin Help explains that receiving DMARC reports indicates that emails are failing DMARC checks. Even if authentication seems correct, the reports highlight discrepancies between the sender's claimed identity and the actual sending source, often due to forwarding or misconfiguration.
22 Dec 2024 - Google Workspace Admin Help
Technical article
Documentation from DMARC.org highlights that misaligned identifiers are a primary reason for DMARC failures. This happens when the domain in the 'From' header does not match the domain used for SPF or DKIM authentication. They also emphasize the importance of consistent domain alignment for successful DMARC validation.
9 Jun 2025 - DMARC.org
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