Email Security Protocols Guide [2026]
Plain-language guides to email authentication protocols. Learn DMARC, SPF, DKIM, BIMI, MTA-STS, TLS-RPT, DANE, ARC, and ARF.
Email Authentication
Protocols that verify sender identity and protect against spoofing.
DMARC Email Auth Guide [2026]
Learn how DMARC protects your domain from email spoofing. Covers DMARC records, policies (none/quarantine/reject), alignment, reporting, and SPF/DKIM.
Read guideSPF Record Syntax & Format [2026]
Learn SPF record syntax, format, and mechanisms. Understand how Sender Policy Framework works, common errors like PermError, and the 10-lookup limit.
Read guideDKIM Authentication Guide [2026]
DKIM adds cryptographic signatures to emails, verifying sender identity and message integrity. Learn how it works, record examples, and key rotation.
Read guideARC Authentication Chain Guide [2026]
ARC preserves email authentication through forwarding. Learn how ARC-Seal, ARC-Message-Signature, and ARC-Authentication-Results work. RFC 8617 guide.
Read guideTransport Security
Protocols that encrypt email in transit and prevent downgrade attacks.
TLS-RPT SMTP TLS Reporting [2026]
TLS-RPT (RFC 8460) monitors SMTP TLS failures between mail servers. Learn how to set up your DNS record, read reports, and fix errors.
Read guideMTA-STS Setup & DNS Guide [2026]
Learn what MTA-STS is, how it prevents TLS downgrade attacks, and how to set up your DNS record and policy file. RFC 8461 guide with provider examples.
Read guideDANE & TLSA Records Guide [2026]
Learn how DANE and TLSA records use DNSSEC to authenticate mail servers. Covers RFC 6698, TLSA configuration, DANE vs MTA-STS, and SMTP security setup.
Read guideBrand & Reporting
Protocols for brand display in inboxes and standardized abuse reporting.
BIMI Record Setup & Validation [2026]
Learn what a BIMI record is, how to create one, and which email clients support it. Step-by-step BIMI setup guide with DNS examples.
Read guideARF Abuse Report Format Guide [2026]
Learn what ARF (Abuse Reporting Format) is, how it powers DMARC forensic reports and email feedback loops, and how to read ARF reports. RFC 5965 explained.
Read guideCompliance
Industry standards that mandate email authentication for regulatory compliance.
Want practical tips and troubleshooting walkthroughs? Browse our email security blog.
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