Introduction

This chapter is a foundation chapter in your study of network security. Without a foundation, it is difficult to build your knowledge of network security. This chapter is also important because it contains terms that you need to understand, along with some of the techniques used by the unscrupulous to compromise security in your network.

This chapter discusses why there is a need, an ever-growing need, for network security in today's organizations, whether those organizations have 3 employees or 100,000 employees . Bottom line: The most secure computer is one that is disconnected from the network completely. But it is also the most useless.

To understand why network security is important, you need to understand some of the techniques used by individuals to attack your network. The discussion of techniques in this chapter is by no means comprehensive. However, the techniques listed provide a general categorization that will help you better understand how hackers break into networks and systems. With this understanding, you will be better able to implement security and respond to the ever-evolving world of hacking threats. Just as hardware and software vendors are continuously improving their products, hackers are continuously changing and improving their techniques to break security.