In this chapter, you learned how to scan your operating system for viruses. You then learned more about how to stop DDoS attacks. Although applications such as Zombie Zapper are not foolproof, they can still help you prepare against such attacks. You should remain current about DDoS attacks and learn more about related tools that can help you recover from this type of security breach. This way, if a system is compromised, you can recover from the event in a graceful way, rather than simply shutting down your system.

You then learned how to scan your system s ports using tools such as Gnome Service Scan and Nmap. The latter program is somewhat more sophisticated, in that it allows you to learn the version of the operating system you are using, the open ports, and the system s TCP sequencing abilities. Nmap is an important tool to understand, because it is used in many other applications, including Cheops and Nessus.

Although not specifically a security application, Cheops enables you to monitor systems on your network, and provides a graphical map. This map is functional, in that you can then right-click on host icons to access these services. Finally, you learned how to use Nessus, a powerful vulnerability scanning tool. Nessus provides you with the ability to update its configuration, and is able to conduct detailed tests of any host on your network.

You now have a thorough understanding of the tools required to lock down and test your system s services. In...