Email Authentication

How SPF, DKIM, and DMARC work together to prove an email really came from your domain.

Featured articles

What Is BIMI? How Brand Logos in Email Work
Brand Indicators for Message Identification (BIMI) lets a domain publish a preferred brand logo for participating …

All Email Authentication articles

What Is BIMI? How Brand Logos in Email Work
Brand Indicators for Message Identification (BIMI) lets a domain publish a preferred brand logo for participating …
VMC vs CMC for BIMI: What Is the Difference?
Verified Mark Certificates and Common Mark Certificates are evidence documents that bind an organization, domain and …
BIMI SVG Tiny PS Requirements and Export Checks
A normal website SVG is not automatically suitable for BIMI. BIMI logos use the constrained SVG …
Why Is My BIMI Logo Not Showing?
A BIMI logo can be absent even when the DNS record looks plausible. Work from structural …
How BIMI Inspection Works: DNS Records, Selectors, SVG Logos and DMARC
Inspecting a BIMI configuration is not one check — it is a sequence of independent, layered …
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Related topics

SPF
Sender Policy Framework: syntax, DNS lookup limits, permerror, and common misconfigurations.
DKIM
DomainKeys Identified Mail: selectors, signing, alignment, and key rotation.
DMARC
DMARC policies, alignment, and aggregate/forensic reporting.
DNS
The DNS record types and concepts email authentication and delivery depend on.
SMTP
SMTP transport, STARTTLS, MTA-STS, and TLS reporting.
Deliverability
Why legitimate email ends up in spam, and how to keep it out of it.
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Free email deliverability tools for domains.

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Email Deliverability Checker SPF Checker DMARC Checker MX Checker
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Knowledge Base Email auth guide Emails going to spam Domain reputation SMTP TLS MTA-STS TLS-RPT
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