IN THIS CHAPTER
Internet e-mail's inner workings
About the system and the software used
Preparing your system
Installing and configuring the mail server software
Testing and troubleshooting
Configuring mail clients
Securing communications with SSL/TLS
Electronic mail hardly requires an introduction. Communications made through the original forms of e-mail helped shape the Internet. Widespread availability of access to e-mail and enhancements such as MIME (Multipurpose Internet Mail Extensions, which allow for inclusion of attachments and alternate message formats) have helped to make e-mail the most popular application on the Internet.
With a Linux system and a suitable Internet connection, you can easily set up your own mail server for personal or business use. This chapter includes a description of how Internet mail works at the protocol level, and then guides you through the process of setting up a mail server, complete with spam and virus filtering. In the final section, you learn how to secure network communications between clients and your mail server through the use of SSL/TLS (Secure Sockets Layer and Transport Layer Security) protocols.
The examples in this chapter are based on a Debian GNU/Linux system. (See Chapter 9 for more information about Debian.) However, much of the knowledge you gain from setting up a mail server in Debian applies to other Linux systems as well.
E-mail messages are generated either by an automated ...