In 2012, a collective of engineers from tech giants like Microsoft, PayPal, Yahoo!, and Google collaborated on fortifying email authentication. The result? The release of DMARC (Domain-based Message Authentication, Reporting & Conformance) – an innovative protocol aiming to bolster email security.

What Exactly is DMARC?

DMARC stands for Domain-based Message Authentication, Reporting & Conformance. It merges DKIM (DomainKeys Identified Mail) and SPF (Sender Policy Framework) checks for enhanced email validation. DKIM verifies email content and its source through digital signatures, while SPF authorizes IP addresses for sending emails under a domain name, commonly used by ISPs like Gmail and Yahoo!.

With DMARC, domain owners set up authentication procedures (DMARC policies) that instruct receiving servers on actions to take if an email fails authentication. Additionally, these policies offer detailed reports, crucial for process improvement and immediate detection of domain spoofing.

Understanding DMARC’s Operations:

DMARC relies on SPF or DKIM records, preferably both. Upon email receipt, the receiving server performs DNS lookups, checks for existing DMARC records, and conducts DKIM/SPF validation. It then executes a “DMARC alignment test” to verify if addresses align correctly.

Alignment tests ensure the “envelope from” email matches the “return-path” address for SPF and that the domain in the DKIM signature matches the sender’s domain. DMARC accommodates “strict” and “relaxed” alignment requirements, ensuring successful verification even if one authentication fails while the other succeeds.

DMARC Policies & Their Impact:

When an email fails DMARC verification, domain owners can set policies:

  • “none”: Observing without influencing deliverability.
  • “quarantine”: Redirecting failed emails to spam folders.
  • “reject”: Immediately discarding failed emails.

Policies can be fine-tuned for nuanced control over email disposition. Despite instructions, servers may not always fully comply, but DMARC significantly enhances control compared to DKIM and SPF.

Additionally, servers generate reports for failed DMARC verifications, aiding analysis and alerting domain owners of potential phishing attempts.


Why Choose DMARC?

DMARC remains the most effective defense against email spoofing. In 2024, major providers like Google and Yahoo mandate DNS email authentication for bulk senders, making DMARC essential.

HMRC witnessed a drastic reduction of 500 million phishing emails after implementing DMARC. Beyond this, two key benefits stand out:

  •  Deterrence for cybercriminals due to DMARC-secured domains.
  • Increased legitimacy for emails from DMARC-protected domains.


Busting DMARC Myths:

  •  DMARC isn’t solely for security but also aids legitimate mail delivery, brand trust, and analytics.
  • All domains, regardless of email-sending capability, require DMARC to prevent impersonation.
  • Initiating DMARC with a “none” policy isn’t sufficient for security; stricter policies are necessary for full protection.


Concluding Thoughts on DMARC:

Email security is paramount, especially for reputable entities. Implementing authentication methods like DMARC is straightforward and yields substantial benefits. Beginning with a “none” policy allows observing checks without impacting deliverability, while receiving detailed reports aids in timely issue identification and troubleshooting.

Check your DMARC Score HERE for free.


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