		Network Security

What is Network Security?

Before we can discuss Network Security, we have to define it.

I'll refine and braoden the definitions in future iterations.

Identifying the "Good Guys"

Account Names and Passwords serve to keep honest people honest. There are many ways to compromise an account’s security. The use of Authentication Services improves security. The use of other means of identification, such as some unique characteristic of the individual (Biometrics), may be required.

This also applies to external resources. Recently an impostor posted a patch for Outlook to many people.

Look at http://www2.idg.com.au/arndb.NSF/Current/NT00008246

Letting the "Good Guys" In

The fundamental purpose of a network is to provide communications. This is true whether those communications are telephone calls, radio messages or data transmissions.

A data network provides digital access to various resources and services. Any organisation using a network will (usually) have installed to serve a particular purpose. That purpose would be to connect Users to those data and tools required to do their jobs.

Thus, part of the job of network administration is to ensure that Users get access to those tools and resources necessary to each of them individually. This means that the security system must allow Users the access they require as simply as possible.

Keeping the "Bad Guys" Out

The Bad Guys includes anyone not authorised to access a particular resource. This includes regular Users as well as irregular ones. Here, too, we lump those unauthorised people commonly called Hackers.

These people should either be restricted to a subset of the network and its resources or excluded altogether.

Maintaining the Integrity of Transmitted Data

Within a Local Area Network we assume that data being transmitted, with the exception of log on traffic, need not be protected from view. Data transiting external networks would normally need to be so protected.

This leads us to the discussion of encryption, on-line transactions and Virtual Private Networks (VPN).