Chapter 45. Firewalls

SOME OF THE MAIN TOPICS IN THIS CHAPTER ARE

What Is a Firewall? 872

Packet Filters 873

Intrusion Detection (Stateful Inspection) 877

Proxy Servers 879

Hybrids 886

Inexpensive Firewalls for SOHO Environments 889

How Do You Know That the Firewall Is Secure? 891

You must be on the Internet if you want your business to remain competitive during the next decade. Yet the Internet remains an insecure territory, much like those in the old Wild West days. To help keep your network protected from people who would try to cause you problems, it is unthinkable for a business in today's market to make a connection to the Internet without using a firewall. The term firewall is casually tossed around by news reporters and in magazine articles, and it might be difficult for you to understand exactly what a firewall is and what it does. That's because a good firewall is not a single entity, but instead a set of components, each of which has a specific purpose. In this chapter, you'll look at some basic firewall technologies and the problems they help prevent. With this knowledge, you'll be in a better position to make decisions about how best to protect your network.