Overview

In this chapter we discuss various concepts of network security, including techniques, issues and problems involved in implementing a safe and secure network environment. The material in this chapter represents an overview of network security, not a detailed treatise.

1. What is network security?

   Network security refers to the proper safeguarding of everything associated with a network. This includes data, media, and equipment. It involves administrative functions, such as threat assessment, and technical tools and facilities such as cryptographic products, and network access control products such as firewalls. It also involves making certain that network resources are used in accordance with a prescribed policy and only by people who are authorized to use these resources.

   Network security is one of the most controversial subjects these days. Everyone wants it, but few even approach solving the problem. Most people usually view "networking" and "security" as two mutually exclusive words. Sure, there are ways to achieve security, but these usually involve serious cash expenditures as well as threats of violence and death to all users of the network. Proper implementation of network security is neither trivial nor cheap, and it requires expertise that encompasses most areas of network science. Box 16-1 provides information about network security and network ethics, which is frequently absent from most discussions involving network security.

   BOX 16-1 Network Security and Ethics

   Network security involves the various measures to protect a network's components and resources from various threats including physical (e.g., fire, natural disasters, environmental,...