checking wireless cable [SORT OF SOLVED]

[Oleg Goldshmidt]

OK, it is sort of solved, but I don't know what combination of
incantations was crucial.

In the hope that it may help someone in the future here is a rough
reconstruction of what I did, minus various futile attempts.

I added PERSISTENT_DHCLIENT=yes to ifcfg-wlan0, commented out
KEY_MGMT=WPA-PSK, and disabled security on the router. I also kept
NM_CONTROLLED=no.

I removed all the *.lease and *.leases files from /var/lib/dhclient.

I restarted the computer. I kept watching /var/log/messages and
iwevent in two terminals to see what was going on.

This led to success - I connected. I concluded that the problem was
related to WPA-PSK in one way or another.

I reenabled WPA2/personal security on the router and set the PSK to a
new value. I uncommented KEY_MGMT in ifcfg-wlan0 and modified WPA_PSK
in keys-wlan0.

This led to an interesting conclusion that despite all this iwevent
still showed that wlan0 operated with "Encryption key: off" which I
thought was weird (wpa_supplicant was running - I checked). As a
result I saw in syslog that there were no DHCP offers and the thing
evenually timed out (multiple times since I kept
PERSISTENT_DHCLIENT=yes). 

I had a hunch that wpa_supplicant was somehow controlled by
NetworkManager which, since I had disabled its control over wlan0, did
not pick up the configuration change. This was a complete WAG (not the
British variety - the American one - wild-assed guess), I really have
no idea what I am talking about here - I could never figure out what
the bloody NM did or did not do - its documentation is
appaling/non-existent. Am I right that it is a GNOME thingy (I am a
KDE user)?

I re-enabled NM_CONTROLLED=yes in the hope that NM would somehow
affect wpa_supplicant. It did - *somehow*, I don't understand exactly
how - but now syslog got flooded with NM messages related to
wpa_supplicant's state changing between "disconnected" and "scanning".
Unfortunately, the link never got to a working state - NM kept issuing
a "link timed out" warning.
 
It was absolutely unclear to me what was going on (googling at various
stages did not help) and on a hunch I went the "Microsoft way" and
rebooted the computer once again (I do not know if just reloading
iwlagn module would help as much). Lo and behold, I had wireless
working after boot!

So now I am basically back to the original configuration, with a
different WPA_PSK and with PERSISTENT_DHCLIENT=yes, but I seriously
doubt either of these changes is actually relevant. It didn't work
until I rebooted, but I had rebooted more than once in the original
configuration, too...

It's got to be simpler. I consider myself to be fairly knowledgeable
and experienced, but it took me quite a while and I still don't know
what the problem was or what the fix was.

Proudly sent through a wireless interface...

-- 
Oleg Goldshmidt | pub at goldshmidt.org