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Linux wifi scanner5/16/2023 This is where things get interesting.Īctive Scanning is the default in just about every device existing. well, lets say I'd win at the lotto every week before that would happen in the wild. The chances of getting two MAC addresses of the same value are. Now - your MAC Address is considered globally unique. In this process, the wifi card transmits a probe request on the currently tuned channel. So we have implementation #2 - mostly referred to as Active Scanning. Sure, you can only run a scan lets say, every 30 seconds - but that still means you have the receiver powered up for 5 seconds out of every minute. We have 12 (or 14 in some areas) channels in the 2.4Ghz band, so a full scan would take 102,400μs x 2 x 12 = 2,457,600μs or about 2.5 seconds.ĭuring this time, the receiver is in a high power usage mode - so battery life is negatively impacted and power usage for a wifi adapter sky-rockets. To have some hope of hearing most Access Points, you'll need to wait for 2 beacon intervals - say 102,400μs x 2 per channel. The beacon (by default) is only transmitted every 100 TU (102,400μs). The scan is completely passive and nothing is transmitted from your wifi adapter. There are two methods of scanning for active WiFi access points.ġ) Turn the receiver on and listen on each channel for the beacon orĢ) Broadcast a "Who is there?" packet on each channel. Wifi is an interesting protocol when you get into the gritty details.
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