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Everyone's doing it can be a really lame reason to jump on board, but wireless was too cool for me to stay away. For me personally, the possibilities were endless. So, I talked to lots of people and then hit google for a long while. What follows is the first installment in a series of articles I am writing in hopes that the reader will benefit from my traveling this road before, as many have before me.

Since this article is specifically about Linux client wireless cards, I don't mention wireless Access Points, but if you're setting up anything more than an ad-hoc network between a couple of machines, you're going to need one. I don't want to mislead anyone into thinking the purchase of one may not be necessary by omitting discussion of them here.

Potential Obstacles

But first, be warned. There are a number of things that can screw up your wireless domination plans. First, wireless, or rather 802.11b specifically, operates within the 2.4GHz spectrum. Guess what else likes that space? Microwaves, cordless phones, and other 11b equipment outside your control. That's right, all three can add noise into your chunk of the spectrum. If you have any 2.4GHz cordless phones, they may interfere with your setup even when they're in their cradles. (I have an 800MHz cordless, so I'm off the hook.) There are other physical barriers as well, like copper piping in your house and even large mirrors in unfortunate locations.

Sadly, the one way to know for sure is to test the waters by setting up your own wireless gear. It is possible to setup a single wireless card and see who else is online in your area, then choose a channel that no one (or few) else is using. As for the phones, if you're serious about 802.11b, you'll have to get rid of them. Consider it part of the cost of adoption. You can't do much about other people's 2.4GHz wireless phones or the internal configuration of your house or complex's piping, however.

In any event, you've been warned.

Which Linux compatible cards do you choose?

The importance of this question cannot be overlooked. You need drivers to make it go, after all. While there are a number of different sets of drivers floating around, including some within the kernel itself, it's safe to say that you have a large number of cards from which you can choose.

The cheaper cards often use Intersil's Prism2, 2.5, or 3 chipset. I personally own a Prism2.5 based LinkSys card and I can vouch for its support under Linux.

Since I originally wrote this in June of 2002, LinkSys has moved at least its PCI line of 802.11b WiFi cards to a BroadCom chipset which is not compatible with HostAP. You can see what the new card looks like here and the BroadCom chipset on the board here. (Thanks to jacques on irc.freenode.net #hostap for these pics!)

D-Link's DWL-650 is moving to the Atmel chipset since April 2002 as noted here at Personal Telco.

The Cisco Aironet cards have support built into the kernel itself and are regarded as being better than the Prism based cards.

Some of the PCI cards require a PCI 2.2 compliant motherboard, such as the DLink DWL-520. The LinkSys WMP11 works fine in a PCI 2.1 compliant system, however.

For a seemingly exhaustive list of cards, chipsets, and driver support status under Linux, check out Jean Tourrilhes' Linux Wireless Drivers page.

I've personally used both the linux-wlan-ng drivers and the Prism2 Host AP driver, both for Prism2 based cards, without any problems; and setup was easy to boot. But, more on that later.

What cards have I used?

Being new to wireless, 802.11b, and wireless on Linux in general, I've only used a few cards. But, I find it useful when I find someone who can personally vouch for success with a specific card or driver before I dive into something new. So, for your reading enjoyment, I'll lay down which cards I've used and which ones worked.

I'm a bit of a fan of LinkSys products, and I've been happy with all my prior dealing with them, so for my host based wireless Access Point I decided I'd go with the LinkSys WMP11 PCI card based on the Prism2.5 chipset. This card isn't a bridged PCMCIA to PCI card, it's a true PCI card and doesn't use the PLX chipset you find on the combined cards.

For my laptop, I purchased LinkSys' WPC11v3 PC Card. I bought this after my US Robotics PC Card failed to function properly.

I also purchased a US Robotics PC Card with a PLX chipset based PCI card. I never tried out the PCI portion, but the PC Card seemed DoA (Dead on Arrival), so I discarded it in favour of the WPC11.

If you're curious about cost (I was), the USR card was available from Outpost.com for $69.95 with a $30 rebate -- hence why I bought it. The WMP11 PCI card was $89.99 and the WPC11v3 was $69.97. I bought the latter two from Best Buy, because I'd have them immediately. They might be a bit cheaper online, but if they didn't work out, Best Buy has a good return policy. (But I digress.)

What do they look like? (Digital cameras are fun!)

I never thought you'd ask.

The LinkSys WMP11 PCI card

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The LinkSys WPC11v3 PC Card

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The US Robotics USR2210/2215 PC Card + PCI Card

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What's next?

Once you've taken the all important first step of choosing and purchasing your new wireless equipment, you'll need to locate the best driver for your card, compile it against your kernel, and install it. Then you'll need to set card values using either the Linux Wireless Extensions utilities or the driver's own utility programs. Finally, you'll need to secure your wireless link via a combination of ethernet card mac address allow and deny lists, WEP encryption, OpenSSH, and IPSec tunneling.

In the next article, I'll discuss getting a Prism2 based card working with two of the available driver sets. (Setting up an Aironet card should be similarly easy, but I do not currently have one.)

In the meantime, I recommend you visit Personal Telco, which has excellent information on WiFi stuff.

Copyright and Revision Information

06-14-02 - Initial Draft
06-15-02 - Additional Sections
07-05-02 - Mentioned the potential need for an Access Point
10-03-02 - Added warning about Prism2 chipset cards mentioned here