FIREWALL

What is a firewall;

The term "fire wall" originally meant, and still means, a fireproof wall to prevent the spread of fire from one place or area of a building to another.
The Internet is a volatile and unsafe environment when viewed from a computer-security perspective, therefore "firewall" is an excellent term for security.

A firewall protects your network/computer from unwanted Internet traffic.
The primary function of a firewall is to let normal or good traffic pass through
while ‘bad’ traffic gets blocked. The most important part of a firewall is its
configuration that distinguish between good and bad traffic.

When installed, a firewall exists between your computer and the Internet.
The firewall lets you browse web pages, download files, chat, etc.
while making sure other people on the internet can not access your computer.
Some firewalls are software that run on your computer like Windows XP Firewall®.
Other firewalls are built into hardware and can protect your network/computer
from attack.

If you have Microsoft's Windows XP there is a firewall built in, by default it
is usually turned on. See "Help and Support" in Windows XP for more information.

Firewall software can be purchased between $40. and $80. at almost any Staples,
EB store, online or large department stores.