Some people say that the only secure machine is one that is switched off. This may be true, but that machine is not very useful. If you want to make your server more functional, you'll have to turn it on and most likely expose it to the curious eyes of the Internet.
Online computer security is a topic large enough to deserve its own book. In fact, a whole shelf of such books is readily available. In this chapter, we will learn basic techniques, which will allow you to secure your server before putting it up online. If your server is exposed to the Internet, it will be a good idea to follow up by doing more in-depth security research and monitor what's happening to your machine on a day-to-day basis. Because this is a book on Webmin, we will only address topics in which Webmin can assist you.
This chapter is divided into three parts:
We'll begin by running through a basic checklist of security issues that every system administrator should keep in mind. We'll point to the recipes...