A firewall is a software or hardware solution that checks incoming data from the Internet or a network, preventing hackers from accessing your PC.
Your operating system typically comes with a software firewall – all you have to do is keep the firewall activated and updated. In addition, most Internet routers have a built-in hardware firewall. The combination of a hardware firewall and an updated software firewall provides excellent security.
Test the strength of your firewall
Use this link to test your firewall strength.
Symantec Security Check