Introduction

Today, more than ever, the security of networks is a major consideration for network administrators. Notwithstanding the risks associated with the fact that most networks are now connected by some means to the Internet, security from a more local perspective is a big issue.

For a network administrator to fully understand the security risks associated with the network, he or she must take a holistic view and consider every aspect, threat, and possible weakness. The network administrator must assume that someone will attempt to gain unauthorized access to the network or the systems attached to it at some point. This might sound a little dramatic, but there are plenty of network administrators who can attest to the fact that it is a reality.

There are, of course, certain environments in which security is more of a concern than in others. If you work for, say, a bank or a branch of the government, security is likely to be a high priority. For a chain of florists in Fresno, security is likely to be less of an issue, but it must still be considered.

Security today is not just about stopping corporate espionage or preventing theft of equipment. It's about protecting the physical assets and, perhaps more importantly, the data of the organization. The cracker coming in through your firewall and entering 50 bogus orders for gift hampers might think it's funny. Your boss is likely to find it less amusing.

In essence, security is about ensuring the privacy, integrity, and quality of a network's data and the systems that hold it, with the purpose of ensuring business continuity. Determining what measures are required to ensure this security is the concern of the network administrator.