Email Authentication

Guides for configuring and troubleshooting SPF, DKIM, DMARC, and other email authentication protocols.

SPF Fail, Softfail, and Hardfail Explained

Understanding SPF authentication results: fail, softfail, hardfail, neutral, and pass. Learn what each result means and how to fix SPF failures.

SPF Multiple Records: Why You Can Only Have One and How to Fix It

Learn why having multiple SPF records breaks email authentication, how to detect this common mistake, and how to merge multiple SPF records into one.

SPF Softfail vs Hardfail: Understanding SPF Results and When to Use Each

Learn the difference between SPF softfail (~all) and hardfail (-all), plus other SPF qualifiers like neutral and permerror, and when to use each in your SPF record.

SPF Too Many DNS Lookups: How to Fix the 10 Lookup Limit

SPF records have a 10 DNS lookup limit. Learn what counts as a lookup, how to diagnose permerror, and strategies to flatten or optimize your SPF record.

SPF vs DKIM vs DMARC: What's the Difference?

SPF, DKIM, and DMARC work together to authenticate your email. Learn what each does, how they complement each other, and why you need all three.

DKIM Fail: Troubleshooting DKIM Authentication Errors

Your emails are failing DKIM checks. Learn what causes DKIM failures, from missing records to signature verification errors, and how to fix them.

DKIM Key Length: Choosing Between 1024-bit and 2048-bit Keys

Learn about DKIM key lengths, why 2048-bit keys are recommended, how to check your current key size, and how to rotate to stronger keys.

DKIM Errors: Troubleshooting Permerror and Temperror

Fix common DKIM errors including permerror, temperror, body hash verification failures, and signature validation problems with step-by-step troubleshooting.

DMARC Alignment Explained: SPF and DKIM Alignment Requirements

Understand how DMARC alignment works, the difference between strict and relaxed alignment for SPF and DKIM, and how to fix alignment failures.

DMARC p=none Explained: What It Means and When to Move Beyond It

Understand what DMARC p=none policy means, why it's a starting point but not a destination, and how to transition to p=quarantine or p=reject.

DMARC Fail: Troubleshooting DMARC Authentication Failures

Your emails are failing DMARC checks. Learn what causes DMARC failures, how to diagnose alignment issues, and how to fix your SPF and DKIM configuration.

554 5.7.5 Permanent Error Evaluating DMARC Policy: How to Fix It

Getting '554 5.7.5 permanent error evaluating DMARC policy' bounces? Learn what causes this error and how to fix your DMARC, SPF, and DKIM configuration.

Email Authentication Failed: How to Fix SPF, DKIM, and DMARC Failures

Understand why email authentication fails and learn how to diagnose and fix SPF, DKIM, and DMARC authentication errors to improve your email deliverability.

Mailgun DMARC Setup: Configure DMARC for Mailgun Email

Step-by-step guide to setting up DMARC when using Mailgun. Configure SPF, DKIM, and DMARC alignment so your Mailgun emails pass authentication checks.