A firewall is a piece of software or hardware that sits between your computer and the internet and acts as the gatekeeper for all incoming and outgoing traffic.
A correctly configured firewall will prompt you when it detects an unauthorised computer or program trying to access your computer or when a software program is installed on your computer tries to make an unauthorised outside connection.
Types of firewalls:
- Hardware (network) firewall
- Software (application) firewall
Both hardware firewalls and software firewalls have user settings which can be changed to create the best compromise between security and convenience. More stringent settings provide greater security, but may interfere with some applications, for example online games, email or VoIP.