The Mail Protocol Suite

One thing to note is that there a several mail protocols and there are differnet ones for sending mail (e.g. SMTP) and reading mail (e.g. POP).

The Most common Mail Protocols include:

SMTP

-- Simple Mail Transfer Protocol (more below)

POP3

-- Post Offce Protocol (more below)

IMAP

-- Internet Message Access Protocol. It is a method of accessing electronic mail or bulletin board messages that are kept on a (possibly shared) mail server. In other words, it permits a "client" email program to access remote message stores as if they were local. For example, email stored on an IMAP server can be manipulated from a desktop computer at home, a workstation at the office, and a notebook computer while traveling, without the need to transfer messages or files back and forth between these computers.

MIME

-- Multipurpose Internet Mail Extensions. Defines the standard representation for "complex" message bodies. A "complex" message body doesn't conform to the default of a single, human-readable, ASCII mail message. Examples of "complex" message bodies include messages with embedded graphics or audio clips, messages with file attachments, messages in Japanese or Russian, or signed messages.