The primary role of a firewall is to prevent unauthorised access to and from your computer. Firewalls can be implemented either in hardware (as a physical device that plugs into your network) or software (as an application that runs on your computer) and provide you with more control over how your computer accesses the internet.

When you are on the internet, each program generally accesses the information via a specific 'port' (as defined by the IANA). A port is basically a door into your computer. A firewall can be used to close unused ports and help protect your computer against various internet worms which attempt to connect your computer via this method. A firewall is NOT a substitute for an up-to-date Antivirus Program, it is an additional level of protection.

There are various software based firewalls available. Some examples are:

• Zone Alarm Pro
• Tiny Personal Firewall

If you are running Windows XP with the latest service pack (i.e. Service Pack 2) you should already have a firewall installed. By default it is activated on all connections. For more information on this, please see the Microsoft website.

All firewalls, both hardware and software, vary greatly in functionality. It is highly recommended that you consult the documentation supplied by the vendor before using one. Also, please note that Technical Support are unable to provide any assistance with any third party software.