Free Tools to Check SPF, DKIM, and DMARC Settings

Tadashi Shigeoka ·  Sat, January 11, 2025

I researched free tools to check SPF, DKIM, and DMARC settings and would like to share my findings.

Background: Improving Email Security and Deliverability

Tools for checking SPF, DKIM, and DMARC settings are crucial for improving email security and deliverability. By verifying these settings are correctly configured, you can reduce the risk of spoofing and phishing attacks while preventing legitimate emails from being filtered into recipients’ spam folders.

Below, I’ve compiled recommended tools for checking SPF, DKIM, and DMARC settings, along with their advantages and disadvantages.

Tools to Check SPF, DKIM, and DMARC Settings

MXToolBox

https://mxtoolbox.com/emailhealth

Overview:

  • A comprehensive tool that can check various items including DNS records and mail server settings. Can verify SPF, DKIM, and DMARC configuration status.

Advantages:

  • Multi-functional, can check various email security issues at once.
  • When issues are found, detailed reports and improvement suggestions are displayed.

Disadvantages:

  • Due to its many features, it may be difficult for beginners to understand how to use it.
  • Some advanced features require payment.

Tools to Check DKIM, SPF, and SpamAssassin

DKIM, SPF, and Spam Assassin Validator - dkimvalidator.com

https://dkimvalidator.com/

Overview:

  • A tool that allows you to check DKIM, SPF, and SpamAssassin validation results together by sending an email to [email protected].
  • By actually sending an email, validation through real email delivery routes is possible.
  • You can check results immediately after changing DNS records (minimizing cache effects).

Advantages:

  • Can check DKIM, SPF, and SpamAssassin scores at once.
  • Since it validates through actual email sending, you can understand the state from the recipient’s perspective.
  • Can test multiple times without resending when DNS records are changed.

Disadvantages:

  • Results display can be somewhat technical and difficult to understand.
  • Detailed reports and improvement suggestions are not provided.

Tools to Check SPF

SPF Surveyor - dmarcian

https://dmarcian.com/spf-survey/

Overview:

  • A diagnostic tool that visually displays SPF records for specified domains and identifies issues.
  • Capable of SPF record syntax checking, authentication server identification, and sending traffic volume verification.

Advantages:

  • SPF records are displayed graphically, making the structure easy to understand.
  • Easy to identify issues (syntax errors, DNS lookup limit exceeded, etc.).
  • If DMARC data is available, can check which IP addresses/includes are being used.

Disadvantages:

  • Some features cannot be used without DMARC data.

Tools to Check DKIM

DKIM Inspector - dmarcian

https://dmarcian.com/dkim-inspector/

Overview:

  • A tool that checks whether DKIM records for specified domains and selectors are correctly published.
  • Checks public key validity, hash algorithms, key types, etc.

Advantages:

  • Can identify DKIM record configuration errors.
  • Can validate DKIM records.

Disadvantages:

  • Cannot use the tool if the selector is unknown.

Tools to Check DMARC Only

DMARC Inspector - dmarcian

https://dmarcian.com/dmarc-inspector/

Overview:

  • A tool that investigates DMARC records, identifies policies, and identifies issues.

Advantages:

  • DMARC record validation.
  • Can check DMARC configuration status and policies (none, quarantine, reject).
  • Displays issues when they exist.

Disadvantages:

  • Detailed reports and improvement suggestions are not provided.

Use these tools to regularly check your SPF, DKIM, and DMARC settings to maintain email security and reliability.

That’s all from the Gemba, where I researched tools to check SPF, DKIM, and DMARC settings.