Introduction

In this chapter, we look at the big picture: what we mean by network security in general and Internet security in particular why it s necessary, how we can create a comprehensive security policy to protect our networks from unauthorized access, and where Microsoft s ISA Server fits into that picture.

Network security is a hot topic and is growing into a high-profile (and often highly paid) IT specialty area. Security-related Web sites such as AntiOnline (www.antionline.com), the Computer Network Security site (www.computernetworksecurity.com), and the Network Security Library (http://secinf.net/) are tremendously popular with savvy Internet users. Esoteric security

measures such as biometric identification and authentication formerly the province of science fiction writers and perhaps a few ultrasecretive government agencies have become almost commonplace in corporate America.

Yet with all this focus on security, many organizations implement security measures in an almost haphazard way, with no well-considered plan for making all the parts fit together. Computer security involves many aspects of safekeeping, from protection of the physical equipment to protection of the electronic bits and bytes that make up the information that resides on the network.

In the next section, we provide a brief overview of what we mean by security in general and how the concept applies to your computer network.

Security Overview

The term