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E-mail server

The simplest possible e-mail server would work something like this:

  • The server would have a list of e-mail accounts for each person who can receive e-mail on the server. It would have a text file, containing header information for each e-mail account, in the directory.


  • There would be e-mail client available at the user end in user's computer.


  • For sending a message, the person would compose a text message using the e-mail client and press [Send] button for sending the message.


  • The e-mail client would connect to the e-mail server and pass to the server the name of the recipient, the name of the sender and the body of the message. The server would format those pieces of information and append them to the bottom of header text-file.


  • While processing the e-mail, the server might add several other pieces of information into the message file, e.g. the time and date of receipt, etc. 

A real e-mail system consists of two different server software running on a server machine. One is called the SMTP (SMTP stands for Simple Mail Transfer Protocol) server software, which handles outgoing mails. The other server software is either a POP3 server or an IMAP server, both of which are capable to handle incoming mails. POP stands for Post Office Protocol, and IMAP stands for Internet Mail Access Protocol.