Recipe for a Linux 802.11b Home Network

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 Published on The O'Reilly Network (http://www.oreillynet.com/)
 http://www.oreillynet.com/pub/a/wireless/2001/03/06/recipe.html
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Recipe for a Linux 802.11b Home Network
by Schuyler Erle
03/06/2001 Related Articles

My introduction to wireless networking was right here at O'Reilly Network,
where our own Rob Flickenger has set up an 802.11b network spanning the
three buildings that house the home offices of O'Reilly & Associates.

The idea of a wireless network was right on my wavelength. "You mean I can
get Ethernet-speed web browsing, file transfers, and the whole works -- with
nary a cable connection in sight -- from as far away as the coffeehouse
across the street? Um, I'll be working from there this morning. IM me if you
need me."

Needless to say, it wasn't long before I started thinking about other
applications for this technology. I wanted Net access on my notebook
computer from anywhere in or near my apartment, too. I started thinking
about how I might control my stereo. I envisioned working on my laptop at a
little garden table on a beautiful day under a stand of trees on my
property, while birds chirp, leaves rustle, a light breeze wafts by, and one
of Beethoven's symphonies blares from my window at, say, 80 dB. Freude!
Naturally, the IEEE 802.11b wireless networking standard was the logical
candidate for a means of implementing this nefarious scheme.

However, OEM wireless "residential gateway" hardware isn't exactly cheap,
running into the hundreds of dollars and even thousands before you even
start thinking about radios for the portables. And bona fide access points
are even pricier. Why go to all that expense, I reasoned, when hardware
that's gathering dust in my friends' closets -- hardware that they're not
using, and would part with for nothing -- will do the job just as well, with
only a little extra effort on my part. People have been using free operating
systems to build dedicated firewalls and routers on i386 and i486 machines
for years. Why not add wireless?

So I set about about building a wireless gateway using Linux, 802.11b, and
an old PC. The project was a stunning success. Doing it right took some
research, and a bit of trial-and-error, but it seemed to me that, in the
end, the task was straightforward enough that anyone with the right hardware
and a little know-how could easily replicate our results. Therefore I've
endeavored to produce my "recipe" for an 802.11b gateway for you to follow
at home. (It didn't hurt that my manager, Peter, was interested in building
one for his house.) Those of you who own the home version of our show should
be able to play along.

Ingredients for a wireless gateway:

1 desktop PC, 386 or better. No, really. You can take that 486/50 out of the
attic, dust it off, and put it to work. We'll call this machine the
"gateway."
1 or more notebook PCs. Each should have at least one free PCMCIA slot.
We'll call these machines the "clients."
Two or more 802.11b wireless Ethernet PCMCIA cards. We like the Lucent
WaveLAN/ORiNOCO cards, but you can in theory use any 802.11b-compliant card.
One ISA-to-PCMCIA or PCI-to-PCMCIA adapter. This should be suitable for
installation on the gateway.
Hardware to set up the link from the gateway to the Internet. This can be a
cable modem, DSL, ordinary Ethernet, another wireless link, a sat