2002-08-16 04:28 UTC Victory (finally)
I found the problem behind my laptop not wanting to connect to the network.
In /etc/sysconfig/network-scripts/ifcfg-eth1, I had set WIRELESS_ENC_KEY to 6346f and not s:6346f as I should have.
Stands to reason really. (In retrospect, I should have suspected the key was wrong sooner, since the packets being sniffed by tcpdump were really quite random. But it would have been nice if iwconfig had said "oh, by the way, the key is wrong", instead of saying "yup, we're connected at 11Mb/s with a medium signal strength". Windows, with the wrong key, is quite clear about the fact you are not connected.)
By the way, Mandrake-like distributions still has some way to go as far as getting a decent location-dependent settings infrastructure for laptops. For example, there does not appear to be a very clear way for me to say "I'm now at home" and then "I'm now at work" and have it automatically change it's wireless encryption key, the time zone, and the volume settings. Or maybe I just haven't found it.