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PC Security: Firewalls - Part One

You probably know that you need a firewall. But the chances are good that you don't actually understand the purpose of the firewall or exactly what it does. Most average users do not - they just (hopefully) know that they need one to protect their PC.

When you think of a firewall, think of an actual firewall that is used to prevent the spread of fire from one area to another. A firewall may be inside of a building, but it may also be outside of a building. For example, when you see a farmer plow up numerous rows of earth around a field that he plans to burn - or a field that accidentally caught fire, he is in essence creating a firewall.

But interior firewalls are what we are discussing here. Those are ultra thick steel walls that will not burn. They are much like the material and structure of a vault. The firewall prevents the fire from gaining access to the area that it was designed to protect. A computer firewall, or network firewall, acts the same way. It prevents access to your computer. It puts limitations that you specify on the programs and data that go in or out of your computer system.

Firewalls come in two flavors: Hardware and Software. In a network, hardware firewalls are often used, but software must also be used to control that hardware. Likewise, without the appropriate hardware, the software has no function. Corporations take advantage of firewalls by allowing all of the computers in the corporation to communicate with each other, and the Internet, but by restricting communication with those computers from the Internet. Internal firewalls may also be used in corporations to prevent some computers from accessing or communicating with others. This prevents information leaks in some cases, and of course viruses in many others.

A software firewall is often referred to as a personal firewall. It is called such because it is used on personal computers more than anywhere else. These types of firewalls use resources on the PC that it is protecting, but they run slower than hardware firewalls.

Firewalls serve to keep both viruses and hackers out of your system. They serve to control the traffic that comes into and goes out of your system. You might think of them as 'gatekeepers.' You control the gatekeeper, and tell it what may and may not come in and out of your system. Obviously, you would allow inbound and outbound traffic for email, inbound traffic for auto-updating software, and outbound traffic to access the Internet.

Firewalls must be educated, but they learn fast. For example, the first time a program - either from the outside or the inside, tries to move past the firewall, the firewall will ask you (the teacher) if this should be allowed. The next time the program tries to move, it will remember your answer.

An open port on your computer is a hackers best friend - and their access to your computers. An open port can be used to gain access to your computer, or to let a worm or some other nasty virus in. Firewalls serve to close any port that is not being used for legitimate reasons, and will restrict traffic through that port while it is open, only allowing movement that you have specified. Furthermore, a good firewall will make the open port invisible, so that a hackers scanning software doesn't see it.

This does not guarantee that firewalls cannot be breached. The firewall is part of the computer system. It is a program just like any other program on your computer. If a virus sneaks in with traffic that you allow, such as email, the firewall can be attacked by the virus.

Now that you understand the importance of a firewall, you may not be so irritated when the firewall alert box pops up. Now, you know that it is just doing the job that you need it to do for you - it is protecting your computer!

  PC Security: Index
  PC Security: Internet Browsers
  PC Security: Spam
  PC Security: Stopping Spam Part 1
  PC Security: Stopping Spam Part 2
  PC Security: Spam Scams
  PC Security: Email Security and Spam
  PC Security: Email Security
  PC Security: Computer Viruses
  PC Security: Protecting Computers From Viruses
  PC Security: Worm Viruses
  PC Security: Trojan Horse Viruses
  PC Security: Rootkits
  PC Security: Removing a Virus
  PC Security: Virus Hoaxes
  PC Security: Server Viruses
  PC Security: Home Network
  PC Security: Cell Phone Viruses
  PC Security: Spyware
  PC Security: Firewalls Part 1
  PC Security: Firewalls Part 2
  PC Security: Parental Control Software
  PC Security: Malware - Spyware and Adware
  PC Security: Data Backups
  PC Security: Pop Up Windows
  PC Security: Safe Public Computer Use

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