This recipe teaches you how to configure Postfix as a basic e-mail server for your domain. E-mail is one of the oldest Internet services and has become one its most pervasive services. Moreover, e-mail can be one of the most difficult services to manage.

Using the Simple Mail Transport Protocol (SMTP), an e-mail message passes through many processes from its starting point on its way to your inbox. When someone writes you a message, they use an e-mail client to compose the message. The client sends the message to their mail server which looks up the MX records for your domain and relays the message to your mail server for delivery. Once the message is received by your mail server, it's delivered to your mail directory on the server. At least that's the basic idea. A message can be relayed by any number of intermediate servers between the sender's server and your mail server; servers can be configured to send mail, receive mail, or both. Different...