This part of the book contains instructions for what to do if your computer's security is compromised. These chapters will also help system administrators protect their systems from authorized users who are misusing their privileges.

• Chapter 24, Discovering a Break-in, contains step-by-step directions to follow if you discover that an unauthorized person is using your computer.

• Chapter 25, Denial of Service Attacks and Solutions, describes ways that legitimate, authorized users can make your system inoperale, ways that you can find out who is doing what, and what to do about it.

• Chapter 26, Computer Security and U.S. Law. Occasionally the only thing you can do is sue or try to have your attackers thrown into jail. This chapter describes the legal recourse you may have after a security breach and discusses why legal approaches are often not helpful. It also covers some emerging concerns about running server sites connected to a wide area network such as the internet.

• Chapter 27, Who Do You Trust?, is a conluding chapter that makes the point that somewhere along the line, you need to trust a few things and people in order to sleep at night. Are you trusting the right ones?