Use firewall software you already haveHere’s how to find it on a Windows:
Windows 8 or 8.1: Press the Windows key until you see the Windows 8.1 Start screen, type firewall, and choose Windows Firewall (not the one “with Advanced Security,” which takes you deep into geekland). (If you use a Windows 7–style menu, press the Windows key to display a search box.)
Windows 7: Choose Start→Control Panel→System and Security→Windows Firewall.
Windows Vista: Click the little Security Center shield in the notification area at the bottom of the screen and then click Windows Firewall.
On a Mac, choose System Preferences from the Apple menu and click Security & Privacy. Then click the Firewall tab and click the Turn On Firewall button.
Use a routerA router is a small box that sits between your computer (or computers) and your broadband modem. Your modem may have a router built in; ask your installer. A router has one plug for a cable to your DSL or cable modem, several plugs (usually four) to which you can connect computers, and usually an antenna for wireless Wi-Fi connections. The router has firewall software running all the time.
As often as not, your DSL or cable modem includes a router, so you’re all set. (If it has a Wi-Fi antenna, or at least four sockets on the back, it’s a router.)
Even if you have only one computer that connects to the internet, you should use a router. If your broadband provider didn’t give you one, it costs about $40 and we’re sure that you’ll want to hook a second computer to the Internet before long. The firewall programs included in Windows 8.1, 7, Vista, and XP work fine, too. Hey, why not use both?
A router is a particularly good idea if you have a broadband connection that is always on (that is, always connected). The router is always on, too.