Click to read our editor's review for Kerio Personal FirewallThe Sunbelt Kerio Personal Firewall helps control how computers share information with other computers through the Internet or a local network. It also protects computers from external or internal attacks from other computers. The Personal Firewall is especially useful for laptop computers since they are easier to compromise because of built-in wireless access.

Basically, a firewall is a program that protects one computer from other computers. It examines information that tries to enter a computer from an outside source (i.e. the internet), and determines if the information is safe or harmful.