Ever wondered what a Firewall is, basically its a piece of software that you just install on your computer and protects you from things like viruses and spyware when you are on the Internet, it does this by monitoring Internet traffic coming from your computer and being directed to your computer.
You can also have a hardware firewall that is built into a wireless router.
It is always advisable to have a firewall installed on your computer as well as Anti-Virus software.
