Network and System Security

CHAPTER 4

Guarding Against Network Intrusions

Tom Chen,* Patrick J. Walsh^†*Swansea University, ^†eSoft Inc.

Virtually all computers today are connected to the Internet through dialup, broadband, Ethernet, or wireless technologies. The reason for this Internet ubiquity is simple: Applications depending on the network, such as email, Web, remote login, instant messaging, and VoIP, have become essential to the computing experience. Unfortunately, the Internet exposes computer users to risks from a wide variety of possible attacks. Users have much to lose—their privacy, valuable data, control of their computers, and possibly theft of their identities. The network enables attacks to be carried out remotely, with relative anonymity and low risk of traceability. ...