Email standards

The main ones are RFC 5321 for SMTP, RFC 5322 for the message format, RFC 7208 for SPF, RFC 6376 for DKIM and RFC 7489 for DMARC. Providers follow them with their own additions, which is why behaviour still varies.

Verifiers rely on the SMTP standard, but receiving servers differ in how they answer, so results are not always conclusive.

• Email protocol
• DKIM
• DMARC
• Email address
• Verify a list
• Topic: Email technical
• All terms