Internet Security - Firewall

A firewall is a security device designed to block unauthorised access to your computer system or network while allowing authorised communications. Firewalls can be carried out with either software or hardware or a combination of both. A computer firewall protects your computer by putting up a barrier to keep anyone from accessing your files when you are surfing the Internet.

Once a hacker get access to your files malicious codes spread through your computer retrieving your personal information that the hacker can use to steal your identity or charge items with your credit card numbers. A firewall not only stops this from happening but keeps the malicious file out of your computer so it can't spread to your other files. That's why it's called a firewall because its job is similar to a firewall that keeps a fire from spreading from one area to the next.

Computer firewall software will allow good data in but blocks all bad data from entering your computer. Good data is when you are surfing the internet, visiting web sites, downloading photos or data files. But bad data, like hacker programs, or anything that spies on your internet habits without your knowledge, is not allowed.

When computer firewall protection is enabled, everything that goes in and out of your computer is monitored. With the amount of malicious programs on the internet today it's also a way to prevent spyware and adware from getting into your computer.

Several types of firewalls exist

• A proxy server while hiding the true network address, intercepts any messages which are arriving and departing from the network.
• Application gateways offer security functions for certain applications like FTP.
• Packet filtering is reasonably effective as it inspects any packet passing through your network and will reject or accept it according to user defined rules
• Circuit-level gateway offers protection when a UDP or a TCP connection is established. Once the connection is in place, packets can move steadily between the hosts without the need for further checking.

In conclusion, a firewall in other words is a shield placed between a protected network and an unprotected one. Its basic task is to monitor the flow of traffic between networks with different levels of trust. Today's internet phenomenon represents a definite untrustworthy zone for the computer user, hence a firewall of some description is mandatory. Once you have installed it it needs to be kept up to date.