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Network Security

NETWORK SECURITY
Threats and Preventive Measures
A basic understanding of computer networks is requisite in order to understand the principles of network security. Quite simply, a computer network is a system of interconnected computers sharing data and physical devices. The data can range from application programs to databases and the physical devices may range from a modem to a plotter.
Network security is a complicated subject, historically only tackled by well-trained and experienced experts. However, as more and more people become ``wired'', an increasing number of people need to understand the basics of security in a networked world.
Network Security
It's very important to understand that in security, there are two extremes: absolute security and absolute access. The closest we can get to an absolutely secure machine is one unplugged from the network, power supply, locked in a safe, and thrown at the bottom of the ocean. Unfortunately, it isn't terribly useful in this state. A machine with absolute access is extremely convenient to use: it's simply there, and will do whatever you tell it, without questions, authorization, passwords, or any other mechanism. Unfortunately, this isn't terribly practical, either: the Internet is a bad neighborhood now, and it isn't long before some bonehead will tell the computer to do something like self-destruct, after which, it isn't terribly useful to you.
This is no different from our daily lives. We constantly make decisions about what risks we're willing to accept. When we get on an airplane, we're accepting the level of risk involved as the price of convenience. However, most people have a mental picture of what an acceptable risk is, and won't go beyond that in most circumstances. If I happen to be upstairs at home, and want to leave for work, I'm not going to jump out the window. Yes, it would be more convenient, but the risk of injury outweighs the advantage of convenience.
Every organization needs to decide...