Electronic Mail  

The phrase "Electronic Mail" is probably used by you almost every day, but do you really know what happens when you press the "Send" button? Do you know what are the components of an Electronic Mail address and how the net 'knows' how to direct the message to its destination ?

Electronic Mail, or E-Mail, as it is known to its many fans, has been around for over two decades. The first E-Mail system was simply some file transfer protocols, and the first line of each message (or file) contained the recipient's address.
As time went on, the limitation of this approach became more obvious.
As experience was gained, more elaborate E-Mail systems were proposed.
In 1982, the ARPANET E-Mail proposals were published as RFC 821 (transmission protocol) and RFC 822 (message format). These have since become the de facto Internet standards.
Two years later, CCITT drafted its X.400 recommendation, which was later taken over as the basis for OSI's MOTIS.
In 1988, CCITT modified X.400 to align it with MOTIS. MOTIS was supposed to be the representing application of OSI, a system that was to be all things to all people .

After a decade of competition, E-Mail system based on RFC 822 are widely used, whereas those based on X.400 have disappeared. The reason for RFC 822's success is not that it is so good, but that X.400 is so poorly designed and so complex that nobody could implement it well. Given a choice between a simple-minded, but working, RFC-822 based E-Mail system and a truly wonderful, but none working X.400 E-Mail system, most organizations chose the first .