RFC 821-Simple Mail Transfer Protocol (SMTP)
RFC 822-standard for the format of ARPA Internet Text Messages ARPA Internet Text Information Format (Header Format) obsoleted by RFC 2822
RFC 974-mail routing and the domain system email routing and domain system (MX Routing)
RFC 976-uucp mail interchange format standard uucp mail exchange format
RFC 1123-Requirements for Internet hosts -- Application and support requirements for Internet hosts
RFC 1321-the MD5 message-Digest algorithm
RFC 1344-significance of mime for Internet Mail Gateway
RFC 1413-Authentication Protocol (ident)
RFC 1652-SMTP service extension for 8bit-mimetransport 8-bit-MIME-SMTP service extensions
RFC 1842-ASCII printable characters-based Chinese character encoding
RFC 1869-SMTP service extensions SMTP service extension (ESMTP Specification)
RFC 1870-SMTP service extension for Message Size notification
RFC 1891-SMTP service extension for sending status notifications
RFC 1892-The multipart/report content type for the reporting of mail system is used to report multiple parts of the mail system management information/report content type
RFC 1893-enhanced mail system status codes enhanced mail system status code.
RFC 1894-an extended Message format for delivery status notifications
RFC 1939-Post Office Protocol-Version 3 Email protocol-Version 3 (POP3) updated by RFC 2449
RFC 1957-some observations on implementations of the Post Office Protocol (POP3)
RFC 1985-Remote Information queuing starts SMTP Service Extension
RFC 2033-local Email Transfer Protocol (LMTP)
RFC 2034-SMTP enhanced error code
RFC 2045-mime Part One: Format of Internet message bodies multi-purpose Internet Mail Extension (MIME) Part 1: Internet Information body format updated by RFC 2231
RFC 2046-mime Part Two: media types mime Part 2: media type
RFC 2047-mime Part Three: Message Header extensions for non-ASCII text mime Part 3: Non-ASCII text header extension updated by RFC 2231
RFC 2048-mime Part 4: registration process
RFC 2049-Consistency standards and Examples
RFC 2060-Internet Information Access Protocol-version 4 (imaprev1)
RFC 2066-IMAP4 ACL Extension
RFC 2067-IMAP4 configuration Extension
RFC 2068-IMAP4 non-synchronous words (literal +)
RFC 2095-imap/pop simple challenge/response to authentication extension (CRAM + MD5)
RFC 2183-the content-Disposition Header field updated by RFC 2231
RFC 2195-imap/pop authorize extension for simple challenge/response
RFC 2197-SMTP service extension for command pipelining
RFC 2202-test cases for HMAC-MD5 and HMAC-SHA-1
RFC 2111-content-ID and message-ID Uniform Resource Locators
RFC 2222-simple authentication and security layer (SASL) Simple authentication and security layer (SASL)
RFC 2231-mime parameter value and encoded word extensions: character sets ,...
RFC 2246-TLS pop
RFC 2251-Lightweight Directory Access Protocol (LDAP) Version 3
RFC 2342-IMAP4 namespace
RFC 2359-IMAP4 uidplus Extension
RFC 2387-the mime multipart/related Content-Type
RFC 2449-POP3 extension mechanism POP3 Extension Mechanism
RFC 2476-message submission proxy (MSA)
RFC 2487-SMTP extension for secure SMTP on TLS
RFC 2505-SMTP MTAs junk information suggestions
RFC 2553-basic interface extension for IPv6
RFC 2554-SMTP service extension for authentication
RFC 2632-S/MIME Version 3 certificate handling
RFC 2633-S/MIME Version 3 message specification
RFC 2821-Simple Mail Transfer Protocol
RFC 2822-Internet Message format
RFC 2831-using digest authentication as a SASL mechanic
RFC 3462-the mime multipart/Report Content-Type
RFC 3463-enhanced mail system status codes
RFC 4406-sender ID: authenticating e-mail
RFC 4408-Sender Policy Framework (SPF) for authorizing use
RFC 4408-Domain-based email authentication using public keys advertised in the DNS (domainkeys)
RFC 4871-domainkeys identified mail (dkim) Signatures
RFC 5617-dkim author domain signing practices (adsp)