Summary
A low DMARC success rate signifies email authentication failures, often due to SPF/DKIM issues or misalignment with the 'From' address, potentially harming sender reputation. Random subdomains are frequently used by spammers to bypass DMARC policies, possibly indicating phishing attempts. NXDOMAIN errors indicate DNS resolution problems or misconfigured sending sources. Fixing these issues involves implementing stricter DMARC policies (starting with 'p=none' for monitoring before transitioning to 'p=reject'), verifying SPF/DKIM configurations, regularly reviewing DMARC reports, correcting DNS settings to resolve NXDOMAIN errors, reporting phishing attempts, and considering services to help interpret DMARC reports. Spam-related DMARC failures are often less critical to address directly than failures from legitimate sending sources.
Key findings
- Low DMARC Success Rate: Indicates SPF/DKIM failures and potential damage to sender reputation.
- Random Subdomains: Often used for spam or phishing attacks, bypassing DMARC policies.
- NXDOMAIN Errors: Signal DNS resolution issues or misconfigured sending sources; troubleshooting involves checking DNS settings and records.
- DMARC Policy: Start with 'p=none' for monitoring, then transition to 'p=reject' for better protection against domain spoofing.
- SPF/DKIM Importance: Proper configuration and alignment of SPF and DKIM are crucial for passing DMARC checks.
Key considerations
- SPF/DKIM Configuration: Verify that SPF records include all authorized sending IP addresses and that DKIM signatures are correctly implemented.
- Regular DMARC Monitoring: Continuously monitor DMARC reports to identify and address authentication issues.
- DNS Management: Ensure DNS settings are correct and updated to prevent NXDOMAIN errors. Check for SPF misconfigurations, outdated DNS entries, and routing loops within email servers.
- Phishing Reporting: Report suspected phishing attempts using your domain to relevant authorities.
- Gradual DMARC Implementation: Implement DMARC policies gradually, starting with 'p=none', to avoid accidentally blocking legitimate emails.
- DMARC Reporting Interpretation: Use services to help interpret DMARC reports, as they can be complex and difficult to understand.
What email marketers say
9 marketer opinions
A low DMARC success rate indicates email authentication failures (SPF/DKIM), damaging sender reputation. Random subdomains in DMARC reports often signal spam or phishing attempts. NXDOMAIN issues relate to DNS resolution problems. Solutions include implementing stricter DMARC policies (p=reject, starting with p=none to monitor), verifying SPF/DKIM configurations, monitoring DMARC reports, ensuring correct DNS settings, and reporting phishing attempts. Services also exist that assist in interpreting DMARC reports.
Key opinions
- Low DMARC Success: Indicates SPF or DKIM failures, harming sender reputation and deliverability.
- Random Subdomains: Often used by spammers to bypass DMARC; may indicate phishing attempts.
- NXDOMAIN Issues: Related to DNS resolution problems; ensure correct DNS settings and updates.
- DMARC Policy Enforcement: Implementing 'p=reject' is effective against spoofing, but start with 'p=none' for monitoring.
Key considerations
- SPF/DKIM Verification: Ensure SPF records include all authorized sending IPs and DKIM signatures are correctly aligned.
- DMARC Report Monitoring: Regularly monitor DMARC reports to identify and address authentication issues.
- DNS Configuration: Ensure DNS settings are correct and regularly updated to prevent NXDOMAIN errors.
- Phishing Reporting: Report suspected phishing attempts using your domain to the Anti-Phishing Working Group.
- Gradual Policy Implementation: Transition to stricter DMARC policies gradually to avoid blocking legitimate emails.
Marketer view
Email marketer from URIports shares that DMARC reports can be difficult to interpret, but are essential for understanding email authentication issues. Services exist to help parse these reports into something easier to understand.
20 Jan 2022 - URIports
Marketer view
Email marketer from Email Marketing Forum shares that random subdomains being used for spam may also indicate someone trying to phish your customers. You should report it to the Anti-Phishing Working Group.
19 Feb 2024 - Email Marketing Forum
What the experts say
5 expert opinions
A low DMARC success rate often signifies unauthorized domain use, typically for spam, with randomly generated subdomains. NXDOMAIN errors indicate the sending server's IP address lacks reverse DNS or a domain name resolution issue. DMARC reporting's primary value lies in identifying improperly authenticated mail from your own sending sources, while noise from spam is less critical. Resolving NXDOMAIN requires verifying and correcting DNS configurations. Effective DMARC implementation involves setting up a DMARC record, continuous monitoring, and a gradual policy implementation, starting with 'p=none' to avoid unintentional mail loss.
Key opinions
- DMARC Failure: Indicates unauthorized use of your domain, often for spam campaigns.
- NXDOMAIN Meaning: Signifies the sending IP address has no reverse DNS or domain resolution problems.
- DMARC Reporting Focus: Prioritize identifying mail you send that isn't properly authenticated, not random spam noise.
- NXDOMAIN Resolution: Involves checking and correcting DNS configurations.
- DMARC Implementation Strategy: Begin with 'p=none' policy for monitoring and gradually increase stringency.
Key considerations
- Monitor DMARC Reports: Continuously monitor DMARC reports to identify and correct authentication issues.
- Correct DNS Configurations: Verify and correct DNS configurations to resolve NXDOMAIN issues.
- Gradual Policy Implementation: Start with 'p=none' and gradually increase DMARC policy stringency to prevent mail loss.
- Spam Noise vs. Legitimate Errors: Focus on fixing authentication issues for your mail rather than worrying about general spam.
Expert view
Expert from Spam Resource explains that NXDOMAIN issues often arise when a sending server attempts to resolve a domain name that doesn't exist or is temporarily unavailable. This can be caused by DNS server problems, misconfigured DNS records, or the domain being recently registered or expired. Resolving this involves checking DNS configurations, ensuring proper DNS server setup, and allowing sufficient time for DNS propagation after changes.
13 Jun 2022 - Spam Resource
Expert view
Expert from Word to the Wise (Laura Atkins) emphasizes that setting up DMARC involves publishing a DMARC record in DNS and continually monitoring the reports to identify and correct authentication issues. Implementing a policy too quickly (such as p=reject) can result in lost mail, so it's crucial to start with a policy of 'p=none' and gradually increase the stringency as you gain confidence in your setup.
29 Jul 2021 - Word to the Wise
What the documentation says
5 technical articles
DMARC failures occur when messages fail SPF or DKIM checks, or those checks don't align with the 'From' address. NXDOMAIN errors in DMARC reports usually indicate a non-existent domain in the sending server's hostname, pointing to misconfiguration. Improving DMARC success involves authenticating all sending sources with SPF and DKIM, and regular DMARC report reviews. NXDOMAIN can stem from SPF misconfigurations, outdated DNS, or routing loops. DMARC is designed to protect domains from unauthorized use (spoofing) by defining policies for messages failing authentication (SPF/DKIM).
Key findings
- DMARC Failure Causes: Failure of SPF or DKIM checks or misalignment with the 'From' address.
- NXDOMAIN Meaning: Non-existent domain in the sending server's hostname, indicating misconfiguration.
- DMARC Improvement Steps: Authenticate sending sources with SPF and DKIM, and regularly review DMARC reports.
- NXDOMAIN Root Causes: Misconfigured SPF, outdated DNS, or routing loops within email servers.
- DMARC Purpose: To protect domains from spoofing via policies based on SPF and DKIM authentication results.
Key considerations
- Authenticate Sending Sources: Ensure all sending sources are properly authenticated with SPF and DKIM.
- Regular DMARC Review: Regularly review DMARC reports to identify and address authentication issues.
- DNS Configuration Management: Keep DNS records updated and correct to prevent NXDOMAIN errors.
- Troubleshooting NXDOMAIN: Use tools like `dig` or `nslookup` to diagnose NXDOMAIN problems.
Technical article
Documentation from Dmarcian explains that 'nxdomain' in a DMARC report typically means that the domain used in the sending server's hostname does not exist. This often indicates a misconfigured or illegitimate sending source.
20 Sep 2023 - Dmarcian
Technical article
Documentation from Google explains that a DMARC failure means that a message failed DMARC authentication. This happens when the message doesn't pass SPF or DKIM checks, or the results of those checks don't align with the domain in the 'From' address.
6 Feb 2025 - Google
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