Protected WLAN

[Tim Smith]

On Monday 23 May 2011 17:50:50 JD wrote:
> On 05/23/11 09:28, Tim Smith wrote:
> > On Monday 23 May 2011 16:36:00 Tim wrote:
> > Not really. This is SSID, not BSSID (BSSID is usually the MAC of the AP).
> > When you scan, you not only listen for beacons, but you (should) send
> > probe requests. If you put an SSID into your probe request, you will get
> > a response only from a BSS with a matching SSID, so you broadcast saying
> > "network named 'MyHouseNetwork' please respond" at which point you get
> > the response from the real BSS which has the real SSID in it and not the
> > bogus one that went in the beacons.
> 
> Well, I have placed wpa_supplicant in full debug verbosity
> output mode, and it's probe/scan does not seem to be aimed
> at just my router. In fact it gets usually 3 to 5 responses
> from which it then selects my AP.
> The wpa_supplicant.conf has the SSID and the BSSID in the
> configuration. So, how come the probe/scan gets more than
> one response?


Well, note I said "If" :-)

If you do not place ANY SSID into the probe request, then all networks will 
respond. Depending on the configuration of a multi-SSID AP you may see more 
than one probe response from the same MAC address in this case. Or not. That 
may be up to the guy who runs the network(s) or it may be a hard-coded 
behaviour of the APs being used.

See the scan_ssid parameter for wpa_supplicant for how to change 
wpa_supplicant's behaviour in this respect.

-- 
Tim Smith <tim at electronghost.co.uk>
"Dude." "Dude." "Dentist." "Dude."
    -- Conversation overheard between two eCos hackers