I thought that it would be automatic and all, but it wasn’t. The most frustrating thing was trying to find any official documentation (howtos, faqs, etc.). Most of the existing pages haven’t been updated since 2003, but the biggest problem is the number of drivers and packages developed over the years (linux-wlan, linux wireless extensions, ndiswrapper), that hindered IMO the development of good high-level configuration packages that configure, enable, and most importantly, troubleshoot the connection.
After a LOT of trial and error, and using this very helpful Ubuntu Forums post, I found the following settings in
/etc/network/interfaces allow me to connect the 3com 3crusb10075 usb wifi dongle (with the zd1121 chipset) to a Linksys AP using WPA2 with the kernel drivers provided. It wasn’t at all obvious that I had to tell wpa-supplicant to enable both WPA and WPA2, as the forum posting called it, but then again it probably appears somewhere in one of the 67(!) pages of replies to that post.
iface eth3 inet dhcp
wpa-proto WPA RSN
wpa-pairwise TKIP CCMP
wpa-group TKIP CCMP
wpa-psk [secret hex thing generated using wpa_passphrase]
Packages I used:
wpasupplicant (0.6.0-1), zd1211-firmware (18.104.22.168-0.1), linux-image-2.6.21-2-k7 (2.6.21-5)