Many good firewalls are available free of charge for private use. A firewall protects your computer against hackers by closing the ports you are not using.
Updating a firewall
Firewalls need to be updated once in a while. Once the update is downloaded, you shut down the program and restart. During this time, your computer may be unprotected. We therefore recommend that you close your connection during firewall upgrades.
Maximising the effect of your firewall
Most firewalls can also easily be closed to block all communication via the Internet. This way, it will seem as if your computer is turned off. Use this function when you are not planning to go on the Internet. It reduces the time available for a potential attack to a minimum.
Tools to help you test your firewall
You may find this external link helpful if you want to test your firewall.
What can happen if you do not use a firewall?
Most computers are set up with all their ports open to the Internet. This set-up allows hackers to attack your computer. A firewall closes the ports you do not use and effectively limits the number of programs where malware can exploit security loopholes.