If you use the Internet, a firewall is a must-have security tool. It isn't the only tool you need, but it's important. It protects your computer from hackers and worms. Hackers are people who attempt to access your computer through the Internet without your knowing it. Worms are programs, such as viruses, that are usually written to do intentional harm.
Windows 10 comes with its own built-in firewall. If you didn't know about it before going online, relax. The firewall is enabled by default. So, most likely, it's been protecting you since the very first moment you went online. (In addition, your Internet service provider protects you from most invasions.) In this chapter, you learn how the firewall works and how to configure it for maximum protection.
How Firewalls Work
To understand what a firewall is, you first need to understand what a network connection is. Even though you have only one skinny set of wires connecting your computer to the Internet (through a DSL phone line or cable outlet), that connection consists of 65,535 ports. Each port can simultaneously carry on its own conversation with the outside world. So, theoretically, you could have 65,535 things going on at a time. Of course, nobody ever has that much going on all at one time. Most people use a handful of ports ...