What is a firewall?

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[Last updated on 17/06/2009, Wed]

What is a firewall?

A firewall is like the security guard of a building. The security guard screens people going in and coming out of the building, trying to prevent suspicious people from entering or thieves from leaving.

In the same way, the firewall tries to stop suspicious data, such as viruses and worms, from entering your computer. It also attempts to prevent data such as your credit card numbers and passwords from being stolen from your computer.


Why do I need a firewall? (Why isn't an anti-virus programme enough?)?

When you leave your house, you lock your doors and windows but even then, thieves may break your windows to gain access to your house. With a security guard, the thieves will have to get past the security guard first before he can even try to break your windows.

Similarly, there are many other computers on the Internet trying to gain access to your computer. This is called probing. Installing a firewall makes it harder for the other computers to know if your computer has a "window" that can be broken into.

Also, the firewall prevents other computers from stealing data, such as your credit card numbers and passwords from your computer.

A security guard would be able to stop the thief from running away with your things. Similarly, a firewall protects your data from being stolen.


What the difference between Windows firewall and Personal
firewall?

Windows firewall
It only monitors incoming connection.

Personal firewall
It monitors both incoming & outgoing connection. (If your computer is infected by spyware, it can still send out information such as your credit card information) internet without your approval.

Click here to download ZoneAlarm's firewall (Free version).


References:

http://www.singcert.org.sg/awareness/firewall.htm
Windows Help and Support


P.S. Some of the information might have typo. Please kindly let me know by leaving a comment at the right side in the chat box. Thank You!

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