This month we'll focus on basic security. If you intend to connect your Linux system to the Internet via telephone, ADSL, cable modem, ISDN or T1, you should give serious consideration to the security of your system. Linux provides a number of built-in security measures but you need to learn how to make them work. Being proactive about security is smart. Before you get into the bells and whistles of Linux, you should learn good system administration practices.
Good security starts with good passwords.
By themselves, good passwords are not enough to keep crackers from gaining control of your system, but they're a critical first line of defense. After looking at passwords we'll take a look at services. If Linux has one fault, it is the tendency for distributions to install a number of services you may not need to be running. These can lead to security weaknesses. We'll learn how to turn off unnecessary services.