Email system/External Links
RFCs relevant to email systems
RFC-5321, "Simple Mail Transfer Protocol", J. Klensin, ed. (2008). IETF Draft Standard.
RFC-5322, "Internet Message Format", P. Resnick, ed. (2008). IETF Draft Standard.
RFC-5598, "Internet Mail Architecture", D.Crocker (2009). IETF Informational document.
RFC-1939, STD-53 (1996), "Post Office Protocol - Version 3", J. Myers, M. Rose, http://tools.ietf.org/html/rfc1939. IETF Standard. POP3, the most common protocol used by mail clients to access a mailstore.
RFC-2045..2049 (1996), "Multipurpose Internet Mail Extensions (MIME)", Parts 1..5, N. Freed, N. Borenstein, K. Moore, J. Klensin, J. Postel, http://tools.ietf.org/html/rfc2045 ... IETF Standards Track. Extensions to allow encoding of graphics and other non-ASCII content in email message bodies.
RFC-3501 (2003), "Internet Message Access Protocol - Version 4rev1", M. Crispin, http://tools.ietf.org/html/rfc3501. IETF Standards Track. An access protocol more versatile than POP3, allowing messages to be organized and kept at the mailstore.