Summary
Troubleshooting and fixing SPF and DMARC settings is crucial for ensuring email deliverability and protecting your domain from spoofing. These authentication protocols work together to verify sender identity, but misconfigurations can lead to emails landing in spam folders or being rejected entirely. Understanding common pitfalls, such as incorrect SPF records, DNS lookup limits, or DMARC alignment issues, is the first step toward resolution. Implementing these settings effectively often requires careful planning and continuous monitoring to maintain optimal email flow.
Key findings
- Interdependency: SPF and DKIM must be set up correctly before DMARC can effectively function. DMARC relies on one or both of these to pass authentication for alignment.
- SPF record issues: Common problems include having multiple SPF records, exceeding the 10-DNS lookup limit, or including third-party senders like Mailchimp or SendGrid in the root domain's SPF when they use their own return-path domains. This can cause SPF PermErrors.
- DMARC policy application: Initially, a p=none (monitoring) policy is recommended to gather reports and identify legitimate sending sources without affecting email delivery.
- Alignment importance: For DMARC to pass, either SPF or DKIM must align with the 'From:' domain. Some ESPs (Email Service Providers) use their own return-path domains, making SPF alignment challenging or impossible, relying solely on DKIM for DMARC pass.
- Forwarding impact: Email forwarding can break DKIM signatures, potentially causing DMARC failures. ARC (Authenticated Received Chain) can help mitigate this by preserving authentication results across relays.
- Continuous process: DMARC deployment, especially moving to an enforcement policy (quarantine or reject), is an ongoing project, taking months or even years, due to evolving sending infrastructures and third-party changes.
Key considerations
- Verification tools: Use online tools to check your SPF, DKIM, and DMARC records to identify configuration errors. This is a critical first step for verifying proper setup.
- Consolidate SPF: Ensure you have only one SPF TXT record per domain and that it includes all legitimate sending sources. Consolidate include mechanisms and remove unnecessary entries like mx if covered by other includes.
- Monitor DMARC reports: Even with a p=none policy, DMARC aggregate reports provide valuable insights into authentication failures and potential spoofing attempts. This data is essential for iterative improvements.
- Address third-party sending: For ESPs that don't allow custom return-path domains (preventing SPF alignment), ensure DKIM is properly configured and aligned. This is often sufficient for DMARC to pass. You can learn more about DMARC failures in this Mailgun article.
- Phased DMARC rollout: Start with p=none, gradually moving to p=quarantine and then p=reject only when confident that all legitimate mail streams are authenticating correctly. This iterative process minimizes the risk of blocking legitimate emails.
What email marketers say
Email marketers often face the immediate challenge of ensuring their campaigns reach the inbox, and SPF and DMARC failures directly impact this goal. Their focus tends to be on practical steps to resolve specific deliverability issues, often seeking quick fixes or specialized assistance to maintain email flow. They frequently encounter situations with multiple email sending providers, each with its own authentication requirements, complicating the setup.
Key opinions
- Immediate need for help: There's a strong demand for consultants who can directly assist with fixing SPF and DMARC settings to resolve deliverability issues.
- Complexity of DMARC: DMARC is seen as a 'deployment' rather than a simple DNS record change, implying a more involved process. This is particularly true when considering how to set up SPF and DKIM for various marketing platforms.
- SPF record challenges: Concerns arise regarding managing multiple SPF records and ensuring they are 'clean' or correctly consolidated, especially with different third-party sending services.
- Misleading warnings: Some online tools might show 'errors' for a DMARC p=none policy, but marketers understand this is typically not an actual issue if the goal is reporting.
- Focus on deliverability: The primary objective is email deliverability, and DMARC reporting is crucial for identifying authentication issues impacting inbox placement, rather than solely preventing spoofing unless it's a direct threat.
Key considerations
- Consultant authenticity: Marketers should be wary of consultants promising unrealistically fast or cheap DMARC deployments, as comprehensive deployment can be time and resource-intensive.
- SPF record optimization: Review your SPF record to ensure it only includes necessary senders and avoids exceeding DNS lookup limits, which could lead to SPF alignment failures or other issues. Sometimes, third-party services like SendGrid or Mailchimp should have their SPF records on subdomains rather than the root domain.
- Leverage DMARC reports: Utilize DMARC aggregate reports from tools to actively track authentication success/failure rates and identify all legitimate mail streams sending on your domain's behalf. This helps diagnose why emails go to spam.
- Prioritize DKIM for alignment: If an ESP does not offer custom return-path setup, focus on configuring DKIM properly, as it can often provide the necessary DMARC alignment.
Email marketer from Email Geeks states they need help with SPF and DMARC settings and that their client is actively hiring for a consultant. This indicates a perceived immediate and technical need.
Email marketer from Kinsta emphasizes that setting up SPF and DKIM authentication is crucial before implementing DMARC to prevent email delivery problems. This foundational step is critical for a smooth DMARC rollout.
What the experts say
Experts in email deliverability emphasize a strategic and often lengthy approach to DMARC deployment, moving beyond simple DNS changes to encompass a full organizational integration. They highlight the importance of specialized tools and continuous monitoring for success. Key concerns include managing the complexities introduced by third-party sending services and balancing the desire for strong anti-spoofing policies with the need to avoid blocking legitimate emails.
Key opinions
- Specialized DMARC services: Professionals with DMARC expertise often leverage suites of tools to streamline setup and management for large organizations.
- DMARC deployment timeline: A full DMARC deployment across an organization can take a minimum of six months and involve significant investment.
- SPF record accuracy: Multiple SPF records are problematic, and the correct ones depend on all sources sending mail. Tidying up SPF records, for example, by removing an mx mechanism if already covered, can reduce DNS overhead.
- DMARC policy interpretation: A p=none DMARC policy is considered a valid and important step for reporting, not an error, despite what some checkers may indicate. This policy is fundamental for simple DMARC setup.
- Third-party ESP impact: ESPs that do not allow custom return-path domains make SPF alignment difficult, increasing reliance on DKIM for DMARC pass. This affects the 'fault tolerance' for aggressive DMARC policies.
- DMARC enforcement complexity: Moving to p=reject is a significant undertaking, requiring continuous vigilance due to external factors (like ESP changes) and internal factors (new services).
Key considerations
- Comprehensive DMARC strategy: Beyond DNS records, DMARC deployment should be treated as an ongoing project, involving tracking aggregate reports and addressing authentication scopes for all outgoing mail streams.
- Understand ESP authentication: Be aware of how third-party ESPs (e.g., Mailchimp, SendGrid) handle SPF and DKIM. Some may use their own return-paths, meaning their SPF records should not be included directly in your root domain's SPF. This often causes DMARC authentication to fail when SPF and DKIM pass.
- Fault tolerance: For aggressive DMARC policies, relying solely on DKIM for alignment, especially when SPF alignment isn't possible, increases risk if DKIM breaks. Consider the implications for legitimate mail being quarantined or rejected.
- Address DKIM failure causes: Troubleshoot DKIM failures stemming from incorrect public records, poor hosting, short key lengths, or message modifications during auto-forwarding. Learn more about these issues from Word to the Wise.
- ARC for forwarding: As DMARC policies become more stringent, ARC (Authenticated Received Chain) helps preserve authentication results through indirect mail flows like forwarding, ensuring DMARC passes where it otherwise might fail.
Expert from Email Geeks generally recommends engaging specialized DMARC companies for DMARC implementation rather than general consultants. These companies offer comprehensive tool suites that simplify the process.
Expert from SpamResource highlights that email authentication mechanisms such as SPF, DKIM, and DMARC are fundamental for verifying sender identity and preventing spoofing. Proper configuration is the essential initial step in any deliverability troubleshooting.
What the documentation says
Official documentation provides the foundational rules and guidelines for SPF, DKIM, and DMARC. It often details the technical specifications, record formats, and the intended behavior of these protocols. The emphasis is on precise configuration and understanding the interaction between these standards to ensure proper email authentication and prevent issues like spoofing and phishing.
Key findings
- Prerequisites for DMARC: Documentation consistently states that SPF and DKIM must be enabled and correctly configured as prerequisites for DMARC to function.
- DMARC record purpose: A DMARC record is a DNS TXT record that provides instructions to receiving email servers on how to handle emails that fail authentication (SPF or DKIM) checks, including reporting, quarantine, or rejection.
- SPF policy failures: When an email is rejected due to SPF policy, it means the receiving server could not verify the domain's sender identity against the published SPF record.
- DMARC TempErrors: These indicate temporary authentication issues related to underlying DKIM or SPF validation, leading to transient DMARC failures. For more details, consult a guide on SPF TempErrors.
- SPF alignment solutions: Fixing SPF alignment typically involves updating the SPF record, adjusting forwarding settings, or contacting the email service provider for assistance.
Key considerations
- DNS TXT record format: Ensure that SPF and DMARC records are correctly formatted as DNS TXT records, following the specified syntax and guidelines. Refer to DMARC record and policy examples.
- Policy progression: When implementing DMARC, it is best practice to start with a p=none policy to gather data before moving to more restrictive policies like p=quarantine or p=reject.
- Understand DMARC tags: Familiarize yourself with the various DMARC tags and their meanings to effectively configure policies and interpret reports. Our list of DMARC tags can assist.
- Review external documentation: Consult resources from organizations like Mailgun to gain deeper insights into how to implement DMARC effectively.
Documentation from DuoCircle defines DMARC TempErrors as temporary authentication issues related to email standards like DKIM and SPF, which can consequently lead to DMARC validation failures. This highlights their transient nature.
Documentation from Mailgun clarifies that SPF and DKIM must be activated to properly utilize DMARC. For SPF, this involves adding a specific DNS TXT record within your domain's DNS settings.
