SMTP History

Before 1960s several different protocols have been used for electronic messaging and communication. These protocols have been developed for mainframe communications.

After mini and personal computers become independent from mainframes, American government designed the first standard (ARPANET) for connection of the different computers to the common network.

By the end of 1970s from the bunch of the different protocols was formed SMTP standard. Development of the SMTP protocol was going on in all 1970s, until ARPANET was converted to the Inernet (as we know it now) in the 1980.

After that SMTP became the widely used protocol for electronic mail transmission. In 1982 SMTP became the standard communication protocol between different computers, systems and networks.

The first email client (Mail Transfer Agent - MTA) using SMTP protocol as a standard became SendMail. At present, the most popular mail clients are: Postfix, Exim, qmail, Microsoft Exchange Server, Sun Java System Messaging Server.

In year 1999 for the purpose of decreasing transmission of unsolicited e-mails (SPAM), mechanism of authorization (SMTP-AUTH) has been added to SMTP. Originally SMTP was based on ASCII charset, so it was not possible to transmit binary data in e-mails. To overcome this limitation, SMTP has been extended to support Multipurpose Internet Mail Extensions (MIME).