Why DMARC Fails When SPF and DKIM Pass
DMARC failures happen even when SPF and DKIM pass because of domain alignment issues. DMARC requires the domain in the "From" header to match the domains authenticated by SPF or DKIM. If this alignment doesn't occur, DMARC marks the email as failed. Here's why this happens:
- SPF Alignment: The "From" header domain must match the domain used in the SPF check (usually the Return-Path domain).
- DKIM Alignment: The "From" header domain must match the domain in the DKIM signature.
- DMARC Rule: At least one of these alignments must succeed for DMARC to pass.
Common causes include:
- Third-Party Services: Email platforms like Google Workspace or SendGrid often use their own domains in DKIM signatures, breaking alignment.
- Email Forwarding: Forwarding changes the sender's IP, breaking SPF alignment, though DKIM may still pass.
- DNS Misconfigurations: Errors in SPF, DKIM, or DMARC setup can disrupt authentication.
How to Fix It:
- Ensure SPF and DKIM records align with your "From" domain.
- Configure third-party services to use your domain for DKIM signing.
- Use DMARC reports to identify and fix issues.
- Implement ARC for forwarding-related problems.
DMARC is essential for email security, but proper setup and monitoring are key to avoid failures.
Why DMARC Fails When SPF and DKIM Pass
Even when SPF and DKIM checks are successful, DMARC can still fail. This happens because DMARC enforces domain alignment, a requirement that SPF and DKIM alone don’t address. Essentially, DMARC ensures that the domains used in SPF and DKIM match the domain in the visible "From" header of the email.
"Alignment is a key concept in the introduction of DMARC; it is the requirement that the domain used for either a passing SPF or DKIM result MUST match the domain of the From header in the email message body." – dmarcian
To resolve DMARC failures, it’s crucial to confirm that both SPF and DKIM domains align with the "From" header domain.
Domain Alignment Requirements
DMARC doesn’t just look at whether SPF and DKIM pass - it checks if the domains used in these protocols align with the "From" header domain:
- SPF alignment: The "From" header domain must match the domain used during the SPF check (usually the Return-Path domain).
- DKIM alignment: The "From" header domain must match the domain in the DKIM signature.
- DMARC rule: At least one of these alignments must succeed for DMARC to pass.
When Domains Don’t Match
The most common reason for DMARC failures, even when SPF and DKIM pass, is domain misalignment. This often occurs when third-party services send emails on your behalf without proper configuration. For example, organizations using Google Workspace, Microsoft 365, or services like SendGrid and ZenDesk may face DMARC failures if these providers use their own DKIM signatures instead of custom ones aligned with your domain. In such cases, the email may pass SPF and DKIM checks but fail DMARC because the authentication domains don’t match the "From" header.
Domain alignment issues can also arise from changes in email routing, such as email forwarding.
Email Forwarding Challenges
Email forwarding can disrupt DMARC alignment because it alters the sending IP address, which breaks SPF alignment, even though DKIM may still pass. Here’s what typically happens:
- SPF fails because the sending IP doesn’t match the original sender’s IP.
- DKIM passes since its verification is tied to the email’s content, which remains unchanged.
- DMARC fails because SPF alignment is broken.
While forwarded emails might not make up a large portion of your email traffic, even a small number of DMARC failures can harm your domain’s reputation with email providers.
"DMARC relies on two underlying authentication protocols - SPF and DKIM. A DMARC pass verdict requires that only one of the two pass, but that the passing protocol(s) also possess a quality known as 'domain alignment', where the checked domain is similar, or in some cases identical, to the domain in the visible From header." – Valimail Help Center
To minimize forwarding-related issues, ensure all outgoing emails are DKIM signed. Since DKIM is less affected by forwarding than SPF, having strong DKIM authentication can act as a safety net when SPF fails due to IP changes during email forwarding.
Common Causes of DMARC Failures
Understanding the root causes of DMARC failures is crucial for resolving authentication issues effectively. While domain alignment is the main factor, there are several scenarios where DMARC can fail even if SPF and DKIM pass individually. These scenarios often involve misconfigurations or challenges tied to specific services, which we'll explore below.
Third-Party Services and DNS Setup Issues
Third-party services like Google Workspace and Microsoft 365 often use default DKIM signatures that may not align with your domain's "From" header unless customized. Similarly, platforms such as SendGrid (for email marketing) or ZenDesk (for customer service) can trigger DMARC failures when sending emails on your behalf without proper domain-specific signing.
DNS misconfigurations also play a significant role. Issues like incomplete SPF records, improperly formatted DKIM signatures, or invalid DMARC policies can disrupt authentication. For instance, if a DKIM-Signature record is missing or contains errors, DKIM authentication will fail entirely. Problems like invalid signing keys - such as RSA keys with incorrect specifications - or failed DNS lookups can further prevent DKIM signature verification. SPF alignment can also break when SPF records restrict sending to specific IP ranges, but emails are sent from other addresses due to load balancing or changes in services. These technical missteps can create significant challenges for maintaining DMARC compliance.
Domain Spoofing and Unknown Senders
Unauthorized senders, whether internal or external, can also undermine DMARC alignment. For example, internal issues arise when departments use unapproved email services, employees enable personal email forwarding, or legacy systems send emails without proper authentication. These legitimate yet misconfigured sources often fail DMARC checks because they're not included in the SPF record or lack DKIM signing.
Email forwarding is another common culprit. Forwarded emails often fail SPF alignment because the forwarding server's IP address isn't listed in the original domain's SPF record. Similarly, mailing lists and email aliases can disrupt DMARC authentication by altering email headers or content, invalidating DKIM signatures, or changing the sending IP address.
To address these challenges, a gradual approach is essential. Starting with a DMARC policy of p=none helps you gather data on authentication failures without immediately blocking emails. This data provides critical insights, allowing you to identify and fix issues before moving to stricter enforcement policies. A clear understanding of these failure points will set the stage for implementing effective solutions in the next steps.
How to Fix DMARC Failures
Addressing DMARC failures involves a step-by-step process that focuses on resolving domain alignment issues, configuring third-party services, and maintaining consistent monitoring. These failures typically occur when the SPF or DKIM domains don’t match the domain in the From header. By identifying the root causes, you can take targeted actions to fix these issues and improve email deliverability.
Setting Up Domain Alignment
For DMARC to work properly, the domain in the From header must align with the domain used in SPF (Envelope-Sender) or the DKIM signature. You can choose between relaxed alignment (allowing subdomains) or strict alignment (requiring an exact match) by adjusting the aspf and adkim parameters in your DMARC record. For example:
v=DMARC1; p=quarantine; aspf=r; adkim=r; rua=mailto:dmarc@yourdomain.com
To ensure proper alignment:
- Verify your SPF record includes all authorized sending IP addresses.
- Confirm your DKIM signatures use your organization’s domain rather than a third party’s domain.
These adjustments strengthen your email security and make it more difficult for attackers to spoof your domain.
Configuring Third-Party Email Services
Once domain alignment is established, update third-party email service configurations to match your domain. Services like Google Workspace, Microsoft 365, SendGrid, and Zendesk require specific DNS updates to ensure compliance. Here’s how to handle this:
- SPF Configuration: Add the third party’s sending IPs to your SPF record and ensure their envelope sender domain aligns with yours.
- DKIM Configuration: Generate a DKIM signature for your domain and work with the service provider to ensure they sign emails using your domain’s DKIM key instead of their default key.
Some third-party services may require you to provide a private DKIM key or publish a key they generate in your DNS records. Many enterprise email providers now offer features to streamline domain alignment for DMARC compliance. When selecting a provider, prioritize those that allow custom DKIM signing and envelope sender customization.
Using DMARC Reports to Find Issues
DMARC reports are your best tool for diagnosing and resolving authentication failures. Start with a DMARC policy set to “none” to gather data without disrupting email flow. Gradually move to stricter policies like “quarantine” and eventually “reject” as you refine your settings.
There are two key types of DMARC reports:
- Aggregate (RUA) Reports: These summarize the authentication status of emails sent on behalf of your domain, showing which messages pass or fail DKIM and SPF validation.
- Forensic (RUF) Reports: These provide detailed information about emails that fail DMARC, SPF, or DKIM checks.
Set up a dedicated mailbox for DMARC reports to review daily insights. Analyze these reports to identify legitimate sources failing DMARC checks and adjust SPF/DKIM settings as needed. For large organizations receiving hundreds of reports daily, consistent monitoring is essential to identify and resolve issues effectively.
Focus on pinpointing legitimate senders that fail DMARC checks and take corrective actions, such as updating SPF or DKIM configurations. After implementing changes, continue monitoring reports to confirm that all authorized senders pass DMARC checks and that your adjustments have resolved the issues.
Handling Email Forwarding
Email forwarding can complicate DMARC compliance because forwarded emails often fail SPF alignment. This happens when the forwarding server’s IP address isn’t listed in the original domain’s SPF record. To address this, prioritize DKIM alignment since DKIM signatures remain intact as long as the email content isn’t altered.
Implement Authenticated Received Chain (ARC) to preserve authentication results when forwarding disrupts SPF alignment. ARC ensures receiving servers can verify that an email was authenticated before it was forwarded.
Use DMARC reports to monitor failures caused by forwarding. Look for patterns that distinguish legitimate forwarding from potential spoofing attempts. Additionally, consult with third-party email security providers to understand how they handle forwarded emails and explore solutions to minimize DMARC failures.
If your organization relies heavily on email forwarding, consider adopting a more flexible DMARC policy to accommodate these scenarios while maintaining protection against spoofing. Regularly review your Suspended tickets view to catch false positives and ensure legitimate forwarded emails aren’t blocked.
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Using Infraforge for Better Email Setup
For businesses grappling with DMARC failures, the process of managing DNS configurations and manual setups can feel like a maze. Infraforge steps in with a streamlined solution tailored specifically for cold email outreach, addressing authentication issues right from the start. Unlike traditional email providers that require manual DNS setup, Infraforge automates the entire process. This ensures businesses maintain the control and deliverability essential for successful campaigns while avoiding the pitfalls of DMARC failures.
How Infraforge Handles DMARC Alignment
DMARC alignment and email forwarding can be tricky to manage, but Infraforge simplifies the process by automating DNS configurations for DMARC, SPF, and DKIM records. By adhering to industry best practices, Infraforge ensures proper domain alignment, eliminating the common mismatches that often lead to DMARC failures - even when individual authentication protocols are correctly configured.
Infraforge also assigns dedicated IPs to each mailbox, giving businesses complete control over their sender reputation without the risks associated with shared IPs. Real-time deliverability monitoring and alerts provide early warnings for potential DMARC issues, helping you stay ahead of problems before they affect your campaigns. A centralized dashboard makes managing domains and mailboxes straightforward, while bulk DNS updates allow instant fixes across all domains. Best of all, the setup process is incredibly efficient - your first domain and mailbox can be ready in just five minutes.
"Infraforge quickly helped to solve a challenge regarding email deliverability. What I like about Infraforge is its ease of use and quality of support." - Silver L, CEO
Infraforge vs. Standard Email Setup
Standard email services like Gmail and Outlook often fall short when it comes to the specific needs of large-scale outreach campaigns. They rely on manual DNS configuration, shared IP addresses, and lack the specialized features necessary for high-volume email efforts. Here's a quick comparison:
| Feature | Infraforge | Google Workspace | MS365 |
|---|---|---|---|
| Dedicated IP | Yes | No | No |
| Automated DNS Setup | Yes | No | No |
| Unlimited Mailboxes | Yes | No | No |
| 5-Minute Ready | Yes | No | No |
| Cost per 200 Mailboxes | $651/month | $1,680/month | $1,200/month |
For businesses managing 200 mailboxes, Infraforge offers a cost-effective solution without cutting corners on essential features. While Gmail and Outlook are great for general communication, Infraforge is purpose-built for outbound email campaigns, focusing on DMARC compliance, deliverability, and reputation management.
"Unlike Gmail or Outlook, we're built specifically for cold email outreach. Each mailbox gets a dedicated IP, automatic technical setup, and built-in tools to maintain high deliverability - even at scale." - Infraforge
These features make Infraforge a powerful tool for businesses looking to scale their cold email campaigns efficiently.
Features for Cold Email Campaigns
Infraforge addresses the unique challenges of cold email campaigns, particularly when it comes to DMARC compliance. Pre-warmed domains and mailboxes allow you to start sending immediately while improving deliverability, skipping the lengthy reputation-building phase that often complicates DMARC setup for new domains.
The platform’s multi-IP provisioning adds an extra layer of protection. If one IP encounters an issue, you can seamlessly switch to another without disrupting your campaigns or compromising DMARC alignment. Infraforge also integrates with popular tools like Salesforge, ensuring a smooth connection between your DMARC-compliant setup and your outreach workflows. For larger operations, the Infraforge API supports programmatic scaling, enabling you to manage hundreds - or even thousands - of mailboxes while maintaining proper authentication across your entire infrastructure.
Customer feedback highlights Infraforge's impact, with users frequently praising its deliverability improvements. The platform currently enjoys a 4.9 user rating, reflecting its effectiveness in solving email infrastructure challenges.
"During my time at a Fortune 500 company and now across all our products, Infraforge has been my go-to solution for Email Infrastructure. Its deliverability and impact are unmatched. If you're serious about outreach and want the best tool in the market, Infraforge is the only choice." - Rahul Lakhaney, Former VP, Gartner, now CEO @ Enrich.so and Maximise
Making DMARC Work Correctly
For DMARC to function as intended, proper domain alignment is a must. Even if SPF and DKIM pass their respective checks, DMARC will fail if the "From" address doesn't match the domains authenticated by SPF or DKIM. This alignment rule is the backbone of DMARC's effectiveness and shapes how it should be implemented.
Start by choosing an alignment mode: strict for exact domain matches or relaxed to include subdomains. Regular DMARC reports play a crucial role here. These reports help uncover why certain emails fail authentication, reveal patterns in your email traffic, and point out unauthorized use of your domain. Aggregate reports provide a high-level overview, while forensic reports dig into the specifics of individual failures. Together, they provide the insights needed to fine-tune your DMARC policy.
The benefits of DMARC are clear. Organizations using it see up to a 90% drop in phishing incidents and a 30% reduction in email tampering. However, it's worth noting that 65% of phishing emails still manage to pass email verification checks.
To implement DMARC effectively, consider a phased approach. Start with a relaxed policy to gather data and refine your SPF and DKIM records based on the insights from DMARC reports. Once you're confident in your setup, gradually tighten the policy for stricter enforcement.
If email deliverability is critical for your business - especially for cold outreach campaigns - specialized platforms can make management easier. Tools like Infraforge streamline complex tasks such as automated DNS setup and dedicated IP management, ensuring proper domain alignment right from the start.
The key to DMARC success lies in combining domain alignment, consistent monitoring, and the right tools to create a seamless and secure email authentication system.
FAQs
Why does DMARC fail even when SPF and DKIM are set up correctly?
DMARC can fail even when SPF and DKIM are set up correctly if the domains in these protocols don't align with the domain in the 'From' address. Here's how it works: SPF requires that the sending server is listed in your SPF record, while DKIM demands that the domain in the DKIM signature matches the 'From' domain. If either of these conditions isn't met, DMARC will not pass.
To avoid issues, especially when using third-party email services, make sure to:
- Update your SPF record to include the servers used by the third-party service.
- Check that the DKIM signature aligns with your domain.
- Review your DMARC policy to ensure it enforces alignment for both SPF and DKIM.
Getting these configurations right is essential - not just for keeping your emails deliverable but also for safeguarding your domain against spoofing attempts.
What’s the difference between strict and relaxed DMARC alignment, and how do you decide which one to use?
Strict DMARC alignment demands an exact match between the domain in the 'From' address and the domain used for SPF or DKIM authentication. This approach provides the strongest defense, making it an excellent choice for safeguarding sensitive communications or preventing domain spoofing attempts.
Relaxed alignment, however, is more forgiving. It allows subdomains to match the primary domain, offering greater flexibility. This can be especially helpful for organizations with intricate domain setups or those just beginning their DMARC journey.
If security is your top priority, go with strict alignment. But if you're looking for a simpler setup or managing multiple subdomains, relaxed alignment might be the better starting point. Many businesses find it practical to begin with relaxed alignment and shift to strict alignment once their configurations are fully optimized.
Why does DMARC fail even when SPF and DKIM pass?
When SPF and DKIM pass but DMARC still fails, the culprit is often domain alignment issues. For DMARC to work correctly, the domains in the SPF (envelope sender) and DKIM (signature) must match the domain displayed in the email's 'From' header. Misalignment frequently happens when third-party services send emails on your behalf or when DNS records aren't set up correctly.
This is where DMARC reports come into play. These reports offer detailed insights into authentication failures, helping you figure out whether the issue lies with SPF, DKIM, or both. By reviewing these reports, you can spot misaligned domains or configuration errors and make precise updates to your DNS records, SPF policies, or DKIM settings. The result? Better domain alignment and improved email deliverability.