After months of banging my head against the wall trying to get my Linksys WPC55AG 802.11 a/b/g card working under RedHat 9.0, I finally figured something out. The most recent madwifi drivers weren't the problem. It turns out that the MAC address filtering on my access point (Linksys BERW11S4) is backwards from what you would expect. Also, in typical Linksys fashion, the documentation isn't the greatest--good enough if you understand the concept, but doesn't provide technical details.
Special thanks to this tech note.
