7

They could just listen to beacons. Why do they probe for every network you've ever connected to?

Do other wireless devices do this? Does Windows, Linux esp. Kali, do this?

6

That is because listening for a beacon and not getting it just might mean that the network has a private ("hidden") SSID. From this article (emphasis mine):

The 802.11 standard allows APs to beacon with the SSID field set to null - this is referred to as a hidden SSID. A client that wishes to associate with an AP using a hidden SSID must first send out a Probe Request that contains the SSID of that network, which will then cause the AP to provide a Probe Response. For any client that does not provide the correct SSID, the AP does not respond.

I believe that probing can be deactivated in Linux; not sure about Windows, but given their history I'd wager that probing is on by default, and may perhaps be disabled through some obscure registry hack.

-1

Another reason is asymmetry - if you see the AP does not mean the AP sees you. Successful active scan guarantees that you can connect to the AP.

  • This answer does not appear to be in line with WiFi protocols. documentation.meraki.com/MR/WiFi_Basics_and_Best_Practices/… – schroeder Nov 12 '17 at 0:56
  • @schroeder Passive scanning means you see the AP, active means you see each other. I don't get what your link has to do with my answer. – Smit Johnth Nov 12 '17 at 17:53
  • What does scanning have to do with subsequent connections? Either way, the device needs to connect ... So, why default to active scans? – schroeder Nov 12 '17 at 17:57
  • Scan results are displayed to the user. There is no need to display APs that doesn't hear our client. – Smit Johnth Nov 12 '17 at 18:03
  • what does that have to do with guaranteeing connection? I do not see the logical connection – schroeder Nov 12 '17 at 18:22

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.