Step 4: Install and use a firewall

A computer without a firewall is like a house without doors—there is nothing to control who or what enters or leaves.

A firewall monitors information going in and out of your computer. It can be in the form of a software program or a piece of hardware. It is designed to let through the websites and files you want to view on the internet and block those that you don't.

Have a firewall permanently turned on as the first line of defence against viruses, spyware and hackers. Always use a firewall, as well as anti-virus and anti-spyware software.

It is important to have a firewall to ensure that you can control what is being installed on your computer. For increased security, any computer or computer networks connected to the internet should have firewall protection.

How to install and configure a firewall

There are two types of firewalls—software firewalls or hardware firewalls. Many people use both forms because most computers and modems often come with firewalls.

Software firewalls

To check if your computer has a software firewall look in the main program menu for any program name that mentions security or firewalls.

It is important to configure your firewall properly so it can protect your computer. Some firewalls have tutorials that can help you configure your firewall properly. You can also look into the help section in your firewall program.

A firewall monitors information going in and out of your computer. according to a predefined set of rules. A firewall cannont block all forums of malicious traffic but it can help stop types of attack.

There is a wide range of other specialist software available that provides a good level of protection. Some software is available as 'freeware', i.e. at no cost to home users, although some of these may have fewer functions. For further details see the SSO factsheet on free security software for non-commerical use.

Hardware firewalls

For people with broadband connections, the dual function modem-router provides connectivity to the internet and the ability to restrict inbound and outbound connections in the same way as a firewall. This helps stop hackers getting access to your computers.

Routers use private address ranges by default for the internal network as an additional security feature which helps protect computers on your home or business network.

If you have doubts about hardware firewalls on any device in your home or office, look up the website of the hardware vendor and do a search for the term 'firewall'.

Further information

Please see advice published by the Carnegie Mellon Software Engineering Institute Installing and Using a Firewall Program.