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How to Use an SPF Records Checker for Accurate SPF Record Validation

  • Writer: go dmarc
    go dmarc
  • Dec 30, 2024
  • 2 min read

An SPF (Sender Policy Framework) record is a DNS record that specifies which mail servers are authorized to send emails on behalf of your domain. Performing an advanced SPF record lookup helps ensure your domain's email authentication setup is accurate and optimized, preventing email spoofing and improving deliverability.

Step-by-Step Guide to Perform an Advanced SPF Record Lookup:



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1. Identify Your Domain’s SPF Record


  • Access your DNS settings through your domain registrar or hosting provider.

  • Look for a TXT record starting with v=spf1. For example: v=spf1 include:_spf.google.com ~all


2. Use an SPF Lookup Tool


To verify and analyze your SPF record, use online tools such as:


  • MXToolbox SPF Lookup: Provides details about your SPF record and checks for issues.

  • DMARC Analyzer SPF Checker: Ensures your SPF record complies with email authentication standards.

  • Kitterman SPF Tester: Validates and visualizes your SPF setup.


3. Check SPF Record Syntax


  • Ensure proper format: Your record should begin with v=spf1, followed by mechanisms and modifiers, and end with an all directive (e.g., ~all, -all).


  • Common mechanisms:


    • ip4: Specifies authorized IPv4 addresses.

    • ip6: Specifies authorized IPv6 addresses.

    • include: References other SPF records.

    • a and mx: Authorizes mail servers based on A or MX DNS records.


4. Validate SPF Mechanisms


  • Check included domains: Use the lookup tool to ensure all domains in include mechanisms are valid and functional.

  • Limit DNS lookups: SPF allows a maximum of 10 DNS lookups. Exceeding this limit can cause the SPF check to fail.


5. Simulate SPF Validation


  • Use tools like SPF Simulator to test email scenarios and verify if a specific sender aligns with your SPF record.


6. Advanced Features to Analyze


  • SPF Flattening: Reduce DNS lookups by consolidating multiple includes into a single list of IPs. Use a tool to automate this process but proceed cautiously to avoid exceeding record size limits.

  • Error Checking: Look for common errors, such as multiple v=spf1 records or missing termination (e.g., no all mechanism).


7. Monitor and Maintain


  • Regular audits: Re-check your SPF record periodically, especially when adding new email services.

  • Combine with DMARC and DKIM: Use SPF alongside DMARC and DKIM to enforce a robust email authentication policy.


Example of a Valid SPF Record:

v=spf1 ip4:192.0.2.1 include:_spf.google.com include:mailgun.org ~all

This record:


  • Authorizes the IPv4 address 192.0.2.1.

  • Includes SPF records from Google and Godmarc.

  • Uses the ~all mechanism, allowing soft fail for unauthorized senders.


By performing an advanced SPF lookup and maintaining a proper setup, you protect your domain from unauthorized email use and ensure legitimate emails reach their destination effectively.

 
 
 

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