What is a firewall used for?
A firewall is software that allows “good” Internet traffic to circulate on your computer and blocks “bad” traffic.
A firewall examines each data packet that enters or leaves your computer. It prevents hackers from accessing your computer, passwords, financial information, and any other type of information stored on your computer.
It also blocks malicious traffic, like worms, which can slow down or stop your system, and Trojan horses that attach your hard drive.