Configuring Linux for sending and retrieving electronic mail can be a complex task but, fortunately, most Linux distributions automatically configure and set up the main email software and directory components during installation. In simple terms, the two types of programs involved in email are as follows:
Transport agents. Programs, such as the sendmail daemon, which send mail files from one computer to another.
User agents. Programs, also called mail readers, such as mail, pine, or Netscape Messenger, used to compose and manage messages.
The sendmail daemon is started when you boot Linux. Its job is to send, not retrieve, email. To retrieve mail over a Point-to-Point Protocol (PPP) interface, or connection, you must ...