Linux Wireless Notes

Summary: These are some notes I put together in mid-November 2004 as I was shopping around for a wireless PCMCIA card for my Linux laptop running Fedora Core 3. I ended up buying the D-Link DWL-G650 for $50 from Fry's. Update (2005-05-29): I dumped a few hours into getting the card to work with Fedora Core 3, but was never able to get it working. Then, I forgot about my laptop and let it get dusty for a few months. One day, I downloaded Ubuntu Linux and after installing it on the laptop, the wireless card just worked. As in, I didn't have to do anything, the operating system actually recognized the hardware correctly, and the GUI to choose the network and punch in the WEP key was simple and intuitive. Wonderful.

Criteria

• 802.11b and 802.11g support. From everything I have seen and heard, 802.11a is DOA.
• Less than $100. This effectively ruled out purchasing a Cisco Aeronet card (which I have used before - if you have the budget, they rock).
• Solid Linux support. For that I headed over to check out the best Linux compatibility list on the Internet. I made a list of all the a/b/g and b/g PCMCIA cards for several vendors (Linksys, Netgear, D-Link) and started digging around.
• Kismet and AirSnort support. This is where I had to start scrutinizing the cards and identifying chipsets. Long story short: Atheros and Prism GT = GOOD, Broadcom (and anything else that requires the use of ndiswrapper) = BAD. Once I narrowed it down to two chipsets, I located the websites for the two drivers to make sure that the cards I had listed were 100% guarranteed to work: For the Atheros chipset, see madwifi.sourceforge.net and the madwifi wiki. For the Prism GT chipset, see prism54.org. Check out the Kismet Documentation page for more info (do searches for 'atheros', 'mad', and 'prism' to find the relevant bits).
• I briefly entertained notions of looking for external antenna connectors and caring about range, but really, just getting the Linux and Kismet support covered chewed up so much time that I had to scrap this one.

Cards Considered

• Linksys WPC55AG (a+b+g, Atheros AR5212 chipset, $100) - Too expensive, didn't need support for 802.11a.
• Netgear WAG511 (a+b+g, Atheros AR5212 chipset, $100) - Too expensive, didn't need support for 802.11a.
• Netgear 511T (b+g, Atheros AR5212/AR5001? chipset, $50) - Ruled this one out as it was not clear whether it uses the AR5001 chipset or the very popular (and thus solidly supported) AR5212.
• Netgear 511 (b+g, Prism GT chipset, $40) - This was the cheapest card, and the Prism GT chipset is fully supported, but I was just getting better vibes from the Atheros chipset (more popular, better documentation).
• D-Link DWL-G650 (b+g, Atheros AR5212 chipset, $50) - Right price, right chipset.

Wireless Tools

• iwlist ath0 scan (list AP's the driver has scanned)
• iwconfig ath0 essid "foo" (set the ssid to foo)
• iwpriv ath0 mode 0 (default - autoselect from 11a/b/g)
• iwpriv ath0 mode 1 (lock operation to 11a only)
• iwpriv ath0 mode 2 (lock operation to 11b only)
• iwpriv ath0 mode 3 (lock operation to 11g only)
• athstats 1