IN THIS CHAPTER
Reviewing Linux mail servers
Installing Postfix, spam-checking, and virus-scanning packages
Adding POP3 support to your mail server
Adding spam filtering
Adding virus scanning
As discussed in the introduction to Chapter 29, "Setting Up a Web Server," most of the significant advances in computing technology have what is known as a killer app (killer application)—one significantly unique, powerful, and compelling type of application that draws people to that technology in droves and makes it a part of the computing landscape for the foreseeable future. For the Internet, this application was the World Wide Web, but for networking in general, this application is probably e-mail. I can't deny that the Internet is the world's biggest and most powerful network, but many businesses already depended on e-mail long before they had access to the Internet.
E-mail can be a tremendous time sink, but it is the lifeblood of much business and personal communication nowadays. Some of the many advantages of e-mail for business communication are that it is asynchronous (you can send mail to anyone at your company at any time, and they can read it as soon as they have the chance) and location-independent (you can send mail to anyone at any location where your company has an office). Personal e-mail allows us to stay in touch with friends and family regardless of where they are. However, all of this requires a reliable transport mechanism ...