RFC2936——HTTP MIME Type Handler Detection
RFC1939——Post Office Protocol - Version 3
RFC2449——POP3 Extension Mechanism
RFC2554——SMTP Service Extension for Authentication SMTP服務認證擴展
RFC2384——POP URL Scheme POP協議的URL方案
RFC1341——MIME (Multipurpose Internet Mail Extensions):
RFC2821——Simple Mail Transfer Protocol（取代了RFC821/974/1869）
RFC2231——MIME Parameter Value and Encoded Word Extensions:Character Sets, Languages, and Continuations
RFC2554——SMTP Service Extension for Authentication
RFC1869——SMTP Service Extensions
RFC2195——IMAP/POP AUTHorize Extension(裏面有關於CRAM-MD5的說明)
RFC2222——Simple Authentication and Security Layer
RFC854——Telnet Protocol Specification
RFC859——Telnet Status Option
RFC959——File Transfer Protocol
RFC2068——Hypertext Transfer Protocol -- HTTP/1.1
RFC3501——INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1
RFC 859 (rfc859) - Telnet Status Option
RFC3261——SIP: Session Initiation Protocol
