So, here was I, happily using the internet over my Airlink card (device ath0) when all of a sudden my internet slows down to next to nothing. Puzzled, I attempt to ifdown and ifup my device (ath0), and imagine my horror when it failed to get an IP address! This laptop -- running WinXP -- also failed to connect, temporarily, but was fixed in short order. The desktop can see the network OK, and reports its signal as "Good" or "Excellent" in KWifiManager, but will she work? Not a chance. Usually I just get "Determining IP address for device ath0... failed" but if I'm really lucky, I'll see "icmp open socket: permission denied." I thought it might be due to WEP -- it seems very like what you get if you enter a wrong key -- so I disabled that, but no joy.
Does anyone have any ideas as to what might be the problem?
/EDIT: KWifiManager looks like this:
Connected to network: MyNetwork
Access point: <my AP's MAC>
Local IP: unavailable
Frequency [channel]: 2.462 
You see - connected, but no IP assigned.