Sharing Your Internet Connection

Evan Kleiman - 2002.09.05

Q. How can I share cable or DSL Internet access with the other Macs in my house?

A. The latest thing that everyone is buying nowadays is broadband Internet access, whether by cable, DSL, or even satellite (only on the PC side so far). With prices dropping lower and lower every day, it seems like no home is complete without broadband. But what if you - like many modern families - have multiple computers in your household, and they all need Internet access?

It was very easy to share dial-up access. All you needed was a modem for each computer, and you were set, as long as you didn't both need to connect at the same time. However, with the "always-on" feature of broadband Internet, things become more complicated. Today I'll tell you how to share your Internet connection with two or more computers.

First we should discuss the benefits of sharing an Internet connection. The first is that everyone can have the Internet at the same time and much faster. This is a big improvement over dial-up access, which only allowed one computer to connect at a time, not to mention tying up the phone line.

Another advantage over traditional dial-up access is that sharing broadband allows each computer to have its own IP address. I could write an entire article on this topic alone, so without getting into too much detail, for our purposes an IP address is like a phone number each computer has. Every time you log onto the Internet (even through a dial-up service such as AOL, CompuServe, or NetReach), an IP address is temporarily assigned to you.

Since broadband Internet is "always on," every computer connected has its own permanent IP address. While this seems simple, it allows you to use nifty features of the Mac OS such as printer sharing and many other cool third-party apps.

Okay, so now that we're done with this whole spiel on why you should share your Internet access with the other Macs (or PCs, but we'll save that for the next article), let's talk about how you actually get this daunting task done.

First, you'll need to have broadband Internet service. Comcast is among my favorites, mainly because they offer support for Macs, especially Mac OS X. This is a welcome service they offer, especially in today's PC dominated computing world. Of course, you might not have any choice about which company you go with in your area.

Once you've got broadband set up, you'll need to make a decision. To connect multiple computers together, you need something called a router. A router can either be a hardware device (something that looks like an ethernet hub) or a software router, which needs a host computer to work correctly. (See Setting Up a Cable or DSL Router for more on routers.)

You can choose either one, depending on your situation. An old 6100 or something of the likes can make an excellent server if you have one laying around. The only limitation is that it will require a USB port (which rules out all the Quadras and pre-PCI Power Macs) or two ethernet ports to work. You can also make your own computer the host, but most people choose not to, because it requires the computer to always be on, and it is likely to slow down your computer.

Because of this, most people chose to use a hardware router, and there are many options available. Netgear, as well as many other vendors, makes hardware routers. And in most places they can be had for less than US$150.

Like many other things, OS X has a built-in software router, called Natd. So if you are using OS X, you can get away without using a program such as SurfDoubler or IPNetRouter. To make things easier, Sustainable Softworks makes a nice piece of freeware called IPNetShareX to help you configure the Natd software router.

Now that you've hooked up the modem and router, you'll need to hook all of your other computers together. We'll do this via ethernet, as most Macs already have a built-in ethernet port. If you're using a software router, you'll need a hub, and once again, Netgear is my vendor of choice, and most ethernet hubs can be had for under US$50. If you're using a hardware router, there may already be a hub inside your router.

After all of this is set up, it's time to configure the router and get online! This is an easy step, but it is different for every brand of router you buy, so be sure to read the manufacturer's instructions.

Once this is all done, it's time to start sharing.