wpa_supplicant works on some occasions, but not others

[Joshua Layne]

Leslie Katz wrote:
> I am not skilled in the use of Linux, but was pleased yesterday to have 
> organised things in accordance with the relevant man pages for the 
> wpa_supplicant system, so that my laptop (running Damn Small Linux 4) 
> connected to my wireless access point (an Apple Airport Express).
>
> Today, however, it wouldn't work. When I ran wpa_supplicant in debugging 
> mode and watched the output, I could see that, although a couple of 
> neighbours' waps showed up in the scans, the Airport Express didn't, 
> even though its name and passphrase were in my wpa_supplicant.conf file.
>
> I know the Airport Express is working, because, at the same time as I 
> wasn't connecting to it in Linux, I was connected to it from a Windows 
> machine sitting beside my Linux machine. I got the Windows machine going 
> a couple of days ago and the wireless card in it came with its own 
> software. I recall that there was a box I had to tick when setting up 
> the wireless connection, which said something like, "Do you want to 
> connect to an access point that isn't broadcasting?" and I ticked the 
> box, because the Airport Express hadn't come up in a scan of available waps.
>
> If the information above is sufficient to permit anyone to offer me some 
> clue as to how to proceed, I'd be very grateful.
>   
Can you post your configuration file? (/etc/wpa_supplicant.conf by 
default on most distros)

It sounds like you are missing:
scan_ssid=1

which (forgive my layman's interpretation) allows wpa_supplicant to 
'sniff' the SSID, even if the AP isn't broadcasting it.

(I am having trouble getting to 
hostap.epitest.fi/cgi-bin/viewcvs.cgi/hostap/wpa_supplicant/wpa_supplicant.conf 
right now to verify that I am right on this)

HTH,
josh