經常使用郵件協議RFC

RFC	描述	狀態
RFC 1939	POP3 protocol	Updated by RFC 2449
RFC 2449	POP3 Extension Mechanism
RFC 822	STANDARD FOR THE FORMAT OF ARPA INTERNET TEXT MESSAGES	Obsoleted by RFC 2822
RFC 2822	Internet Message Format
RFC 2045	MIME Part One: Format of Internet Message Bodies	Updated by RFC 2231
RFC 2046	MIME Part Two: Media Types
RFC 2047	MIME Part Three: Message Header Extensions for Non-ASCII Text	Updated by RFC 2231
RFC 2183	The Content-Disposition Header Field	Updated by RFC 2231
RFC 2231	MIME Parameter Value and Encoded Word Extensions: Character Sets,...
RFC 2387	The MIME Multipart/Related Content-type
RFC 3462	The MIME Multipart/Report Content-type
RFC 2111	Content-ID and Message-ID Uniform Resource Locators
RFC 2632	S/MIME Version 3 Certificate Handling
RFC 2633	S/MIME Version 3 Message Specification
RFC 2821	Simple Mail Transfer Protocol