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Old 04-11-2005, 11:59 AM   #1
hjd17
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Registered: Aug 2003
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iwlist and active scan


Does any know if when you do iwlist wlan0 scanning, does it perform an active scan or a passive scan. Or is it completely based on the drivers.
 
Old 04-12-2005, 09:37 AM   #2
David_Moses
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Registered: Jul 2004
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I am also interested in the answer to this question

my thoughts......

ALL ap broadcast becons, they can be moded so they don't braodcast ESSID's but they must tranmitt becon frames to sysc clients, etc.

I think Iwlist switches to a channel and listens for a period of time for all becon frames tranmitted on the freq.

eg.

it takes 2.677 sec for me to do a iwlist scan, therefore my client 'listens' on each channel for 0.243 sec, or 200ms

I think the maximum time that AP have between broadcasts is 100ms. So it should always pickup AP in range.

So my thoughts are that lwlist is a passive scanning tool.

However, i read somewhere that passive scans can only happen the the scanning card is in RFMON mode, which means it cannot tranmitt.
But am running scans while writing this post on the internet,
So this kind of points to active scanning.

Confused....
 
  


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