New World

1 modem and 4 PCs

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JAMAIS CASCIO advises suits and other Hollywood weasels on what could happen over the next hundred years. He worries about being called a futurist.

I have more than one computer at home. How do I connect them all to the net?

To answer this question, I have to start with a bit of a description of my home-office.

I'm writing this on a new PowerMacintosh G3, one of those blue & white computers that's so funky-looking that you either want to display it proudly on your desk or bury it underneath. 128MB RAM. 350MHz processor. Fast doesn't even begin to describe it, and the DVD and Zip drives leave me asking "floppy? who needs one?" Yes, I'm very happy with it.

I'm also (mostly) happy with my PC. I still play lots of computer games, and Windows is absolutely necessary for that. I have a nice wide desk, and the mac lives on the right hand side, the PC lives on the left. Two 17" monitors stare balefully at me; various speakers, business cards, and lego toys fill the space between them. Just to complete the picture, my wife Janice is very happy still on her aging PowerCenter 240, and my good old IBM ThinkPad 560 - an archaic Pentium 133 in a wonderful 2 kilogram package - sometimes joins in on the fun.

The problem with having more than one computer is getting them all hooked up onto the net. It's not unusual for me to be working online and have Janice come in and want to check her mail; I've also found myself playing a network computer game on the PC and want to look up maps and guides on my Mac at the same time. The phone company would love to sell me multiple phone lines, one for each computer, but this is at best a costly and inefficient solution, and one that may not even be available in most of the world. My wife and I could simply wait turns, getting a modem for each computer and making the other person feel guilty about spending so much time online.

Or we could use NAT.

NAT -- Network Address Translation -- is a very cool type of software. What it does, simply, is take the internet address it gets when it dials up to the Internet Service Provider and split it into multiple internal addresses for everyone else in the house. NAT software, also known as IP Masking or IP Masquerading, is available for every operating system around, and is even built-in to the just-released updated version of Windows 98. With NAT, only one machine needs a modem, and all other machines in the home share that modem connection.

Setting up NAT at home is pretty straightforward, but does require some hardware that might not be in a typical PC.

First of all, you have to have ethernet connections for all of the machines. Ethernet is a way of networking together computers, and the cables and plugs look like fat phone lines. Every machine you want to include in your little home network needs its own ethernet card. Fortunately, these are remarkably inexpensive these days for PCs, and every new Macintosh sold over the last 3 years has come with ethernet built in.

Second of all, you'll have to have an ethernet hub to connect the machines together. A hub lets you plug in 4 or more machines to the same ethernet network. Even if you only have 2 machines now, a hub is worthwhile, since it lets you add more machines (or even a network-connected printer) in the future.

Third of all, you'll have to have one computer with a fast modem. You'll be sharing that one modem's connection between all of the computers, so you want a good fast 56K device. Remember that the machine with the modem must be running for any of the other machines on the network to be able to connect out. This is something that takes some getting used to; it's easy to accidentally turn off your machine when you're done, and take down the connections for everyone else.

One of the advantages to using NAT is that it functions something like a firewall for your home computers. A hacker could, at best, really only get into the machine with the shared modem; the other machines would be safe. Security and the accidental shut-down problem are good reasons to use an inexpensive extra computer as the modem server, rather than one of the user's machines. I use an old PowerMac running IPNetRouter (from Sustainable Softworks) as my NAT server. An old PC running Linux is another good solution, using the free IP Masquerading software.

NAT is also very useful if you are lucky enough to live where cable modems or DSL (high speed phone lines) are available. Most of these services only provide a single internet address; if you want multiple addresses, you have to buy the business service, for much more money. For home users who simply want to be able to check mail and play network games on more than one machine, NAT is the perfect solution.

I may be a bit unusual right now with more computers than there are people in my house. As more households around the world get comfortable with digital technology, however, this situation will become much more common. Linking the machines together in a home network lets you share your resources, cut your costs, and let everyone online. Not a bad solution, at all.

© Daily Mail & Guardian - 04 August 1999

* Jamais Cascio is a consultant and writer specializing in scenarios of how we may live over the next century. His clients have included mainstream corporations, film and television producers. He has written for many publications, including Wired and TIME, and is currently working on a screenplay. He is an active member of the oldest and most influential online community, The Well, and believes that new technologies are pushing people into new social, economic and political realms.

Published weekly by the Electronic Mail & Guardian, Johannesburg, South Africa. Send email comments to the editor, Gavin Dudley