Summary

This chapter provided a look at intrusion detection tools and some basic security principles. From things like TCPDump, to sniffer placement, to filesystem integrity, the chapter showed you around the world of intrusion detection.

These intrusion detection tools are best when coupled with security practices such as regular updating, enhanced security measures, and penetration testing to ensure that the security of the system is as you expect.

The next chapter of the book looks more in-depth at network security by examining TCPDump, a key tool in any administrator's toolbox.