Every RFC referenced in Email Decoded, tracked in one place and kept current as the standards evolve — from SPF and DKIM to the new DMARCbis suite, ARC, BIMI, SMTP, MIME, and email encryption.
Defines SPF syntax, the 10 DNS lookup limit, and evaluation mechanics.
Core DMARCbis protocol: alignment, policy enforcement, np= tag, t= tag, DNS Tree Walk.
Supersedes: RFC 7489
Defines the aggregate report XML schema, discovery_method, and required selector/scope fields.
Defines failure report format, privacy redaction requirements, and rate limiting for ruf= reports.
Preserves original authentication results across forwarding intermediaries via ARC-Seal, ARC-Message-Signature, and ARC-Authentication-Results headers.
Defines the BIMI DNS record, SVG Tiny PS logo format, and VMC certificate requirements.
Core SMTP protocol including the MX/A record fallback behavior and response code structure.
Defines header/body structure, header folding, and the From/Date requirement.
Defines the 8BITMIME extension for raw UTF-8 transport without encoding.
Defines the null MX record for signaling non-mail-accepting domains.
Defines Content-Transfer-Encoding, Base64, and Quoted-Printable.
Defines multipart/mixed, multipart/alternative, and multipart/related.
Defines encoded-word syntax for non-ASCII header content.
Defines the HTTPS-published policy mechanism to enforce TLS and block STARTTLS stripping.
Defines the reporting mechanism that pairs with MTA-STS.
Defines DANE/TLSA certificate pinning via DNSSEC-secured DNS records.
Recommends IANA registration over the ad-hoc X- header prefix convention.
Defines List-Unsubscribe-Post for one-click unsubscribe.