Resolving SPF Permerror: Step-By-Step Guide
To Correcting SPF Records


Sender Policy Framework (SPF) is a critical email authentication protocol designed to protect domains from email spoofing. However, misconfigured SPF records can lead to a Permerror (Permanent Error), which disrupts email deliverability and exposes your domain to security risks.

In this guide, we’ll break down the causes of SPF Permerror and provide a comprehensive step-by-step approach to resolving and optimizing your SPF records for smooth email delivery and robust security.


Understanding SPF Permerror


An SPF Permerror occurs when an email fails authentication due to a permanent error in its SPF record configuration. Unlike temporary errors, which might resolve with retries, a Permerror indicates a structural or syntax issue that requires manual intervention.



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Consequences of SPF Permerror

  • Email Rejections: Legitimate emails may fail to reach their intended recipients.

  • Spam Placement: Emails may land in spam folders due to failed authentication.

  • Security Vulnerabilities: Attackers can exploit poorly configured domains for phishing and spoofing.

  • Reputation Damage: Ongoing failures can harm your domain’s sender reputation with email providers.

Common Causes of SPF Permerror


  • Exceeding the 10 DNS Lookup Limit: SPF records are restricted to a maximum of 10 DNS lookups during the authentication process. Surpassing this threshold will lead to a Permerror. Additionally, errors in syntax within the SPF record—such as absent spaces, erroneous tags, or typographical mistakes—can result in failures during authentication.

  • Circular References include Mechanisms: When domains referenced in the SPF record loop back to each other, it creates recursive lookups.

  • Misconfigured Domains: The domains listed in the SPF record may be either outdated or improperly configured.

  • Unnecessary Mechanisms: Excessively populating the SPF record with unnecessary mechanisms or entries may lead to the occurrence of errors. Read our comprehensive guide.

Step-By-Step Guide to Fixing SPF Permerror


Step 1: Identify the Error

  • Utilize resources such as the MXToolbox SPF Checker or the Kitterman SPF Validator to examine your SPF record.

  • These utilities will identify the precise problems leading to the Permerror.

Step 2: Simplify the SPF Record

  • Audit the Record: List all mechanisms (include, ip4, ip6) in your SPF record.

  • Eliminate Redundancies: Remove duplicate or unnecessary entries.

  • Flatten the Record: Replace include mechanisms with specific IP addresses or ranges where possible.

    • Example of a simplified SPF record:

    v=spf1 ip4:192.0.2.1 ip4:198.51.100.1 include:example.com -all


Step 3: Reduce DNS Lookups

  • Combine Mechanisms: Utilize CIDR notation to consolidate several IP address ranges into one comprehensive entry.

  • Use Subdomains: Allocate email-sending functionalities among various subdomains to minimize the frequency of lookups for each domain.

  • Employ SPF Flattening Tools: Utilize services that simplify your SPF record by substituting include mechanisms with direct IP addresses.

Step 4: Fix Syntax Errors

Make sure that the SPF record starts with v=spf1 and concludes with a clear directive such as -all or all. Additionally, refrain from using spaces or any unsupported characters within your record.

Correct syntax example:

v=spf1 ip4:203.0.113.0/24 include:spf.protection.example.com -all


Step 5: Resolve Circular References

  • Utilize SPF diagnostic tools to analyze include mechanisms and detect any loops.

  • Substitute any problematic includes with direct IP addresses or more efficient references.

Step 6: Validate All Referenced Domains

  • Ensure that all domains listed in the SPF record are correctly set up and operational.

  • Eliminate or revise any domains that are inactive or no longer in use.

Step 7: Test the Updated Record

  • Update your DNS with the revised SPF record.

  • Utilize email testing tools to ensure that emails are successfully authenticated through SPF.


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Best Practices to Prevent Future SPF Permerror


  • Monitor DNS Lookups: Regularly check your SPF record to ensure it complies with the 10-lookup limit, including nested lookups. Use SPF analysis tools to identify issues and improve your setup. Consider optimizing IP addresses and includes to reduce unnecessary lookups while maintaining critical functionality.

  • Use Additional Authentication Protocols: Implement DMARC and DKIM alongside SPF to create a robust email authentication strategy. These protocols enhance domain alignment and provide cryptographic verification, reducing spoofing risks. Consistently monitor DMARC reports to identify unauthorized email activities and evaluate the effectiveness of your authentication efforts.

  • Update Records Periodically: Consistently update your SPF record whenever you alter your email-sending services to ensure its precision and efficiency. Create a routine for reviewing your domain's DNS settings to effectively manage changes in your email infrastructure. Also, confirm that new services align with existing authentication policies without complicating lookups.