Technical Standards (RFCs & Protocols)

The "engineering" blueprints. This section covers the foundational RFCs (Request for Comments)—the "magic" documents that define everything: RFC 5321 (SMTP), RFC 5322 (Message Format), RFC 6376 (DKIM), etc.

15 questions in this topic

What is an RFC (Request for Comments)? Who maintains RFCs? What are the most important RFCs for email (5321, 5322, 7208, etc.)? What does RFC 5321 define? What does RFC 5322 define? What’s the difference between SMTP, MIME, and ESMTP? What is RFC 6376 (DKIM)? What is RFC 7489 (DMARC)? What is RFC 8617 (ARC)? What is RFC 8461 (MTA-STS)? What is RFC 8460 (TLS Reporting)? What is RFC 7208 (SPF)? What is RFC 8058 (List-Unsubscribe)? How do RFCs evolve and become deprecated? What are common RFC compliance issues that break deliverability?

Questions about Technical Standards (RFCs & Protocols)