Eyebrows will rise. You can then explain that a firewall is simply a lock on your computer to keep intruders from stealing sensitive information inside. Most of us lock our house doors when we go out. Some of us even install security systems. Unfortunately, many of us who are otherwise so cautious leave the doors to our PCs wide open.
Firewalls can be either hardware or software.
Personal firewalls meant for home users usually aren't as strong as corporate firewalls, but they're easier to use and configure. In some cases, a properly configured firewall can even make your computer appear invisible to a hacker. To understand how a firewall works you must know some basic networking concepts. Every computer connected to the Internet has a unique digital identity known as an IP address. Each address comprises four sections separated by periods and each section contains a number between 0 and 255.