At one time, a typical Mac user would no more have connected a couple of computers to the Internet via a local network than they would have extracted their own kidney. If you just mentioned the word networking (outside the context of calling former business associates to seek a better job), those around you shook with fear.
Blessedly, those days are almost entirely over. Now, just about anyone can configure and join a network. Let's see how it's done.
A little background
I'm going to assume that you already have some variety of Internet service--along with a broadband modem (the box that brings broadband Internet service into your home or office) that includes or is connected to a router (a device that distributes network addresses to computers and mobile devices connected to it). When you signed up for that service, either someone installed it for you or you were sent the gear you needed and you followed the instructions necessary to connect to the Internet.
In most cases, the modem/router relationship works this way: Your Internet service provider assigns something called an IP address to your Internet account. This address is selected from a range of addresses that the ISP owns, and it can change depending on the kind of account you've signed up for. (If you have a static account, you'll always have the same IP address; if you have a dynamic account--which is most common--your IP address can change.) This IP address is your main thoroughfare to the Internet.
The router, as its name implies, routes devices connected to it (either with a wire or via Wi-Fi) so that they can access your Internet connection. The router creates a number of internal IP addresses--private addresses used only within your local network. When you log on to your network with your Mac or an iOS device, it's assigned one of these addresses. An easy way to think of a local IP address is as the device's network name--like Shane, Courtney, Anastasia, or Gub-Gub--only in this case, the name is represented by a string of numbers separated by periods (192.168.0.22 or 10.0.1.29, for instance).
I don't want to burden you with a load of technical terms, so perhaps an analogy will help you understand how they all fit together. Imagine that the IP address assigned by your ISP is a road in front of your house. The modem is your home's driveway. The router is the home itself. And the router's IP addresses are the many doors you use to enter and exit your home.
Configuring the Network preference
Now that the theory portion of the lesson is over, let's move to its practical application by choosing System Preferences from the Apple menu and selecting the Network preference.
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