You probably don't know the answer but what allows WiFi scanning anyway?

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SUMMARY:
What service is it that does the Wi-Fi scanning on Android anyway?
http://i.cubeupload.com/lYvIsQ.jpg

DETAILS:
You probably don't know the answer but what allows WiFi scanning anyway?

In the past few weeks I changed so many things on my Android 4.3 phone that
I don't remember what killed WiFi scanning but I just want to ask, in case
someone knows, what actually does the WiFi scanning on an Android phone?

For example, I have over a half dozen access points at home, all being
broadcast in the clear, WPA2/PSK-AES protected, which the third part
programs find with no problem (e.g., Fritz! WLAN, WiFi Manager, WiFi
Connection, WiFi Analyzer, InSSIDer, WiFi Analysis, WigLe WiFi, etc.).
http://i.cubeupload.com/fV8D4d.jpg

Some (but not all) of the 3rd-party apps can find all the networks, yet,
the scan button in Android 4.3 doesn't find a single network anymore.
What on Android does the scanning anyway?
http://i.cubeupload.com/TNGRGg.jpg

I can certainly manually press the default Android 4.3 "Add Wi-Fi network"
and then it will connect to any network I manually type in, but it won't
*find* a network on its own anymore, even though the signal strength is
clearly in the negative forties, fifties, sixties, and seventies (i.e., the
signal strength is just fine).
http://i.cubeupload.com/lYvIsQ.jpg

I realize probably nobody knows the answer but just in case you do, what
service on Android does the WiFi access-point scanning anyway?

Re: You probably don't know the answer but what allows WiFi scanning anyway?
On Sun, 19 Mar 2017 18:08:33 -0800, Stijn De Jong

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Wrong question.  What you should be asking is what disables wi-fi
scanning.  That's easy, 2 ways.
1.  If your phone is setup to act as a hot spot so that others can
borrow your cellular data bandwidth, it will kill scanning.  That's
because a hot spot requires that the channel number be fixed and not a
moving target.
2.  If your phone is in peer to peer mode instead of infrastructure.
There are many reasons for this to happen.  For example, printing
directly to an HP ePrint printer or Apple Airprint printer.  I think
(not sure) that a GoPro camera connection does the same thing.

Note that the phone cannot be in infrastructure (what you want) and
peer-to-peer mode (what you don't want) at the same time.

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I'll take the easy way out and claim ignorance.

--  
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: You probably don't know the answer but what allows WiFi scanning anyway?
On Sun, 19 Mar 2017 20:26:25 -0700, Jeff Liebermann wrote:

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Those are both good answers as to what disables wifi scanning.

The phone has never been set up as a hotspot since the last factory reset,
although it certainly would be possible to set it up as a hotspot since
it's T-Mobile which allows that on all their phones. But it's not currently
set up as a hotspot to my knowledge. But that's an interesting observation.

I'm not sure what "peer-to-peer mode" is for Android.

Googling  
https://www.google.com/search?q=android+peer-to-peer+mode

I found this:
https://developer.android.com/guide/topics/connectivity/wifip2p.html
Which says that two Android devices can connect in peer-to-peer mode (aka
WiFi Direct).  

I have never used WiFi Direct so I don't think it's in peer-to-peer mode.
Besides, the phone connects to WiFi when I manually type in the (very long
complex) SSID.  

It just won't find any SSID when I press the scan button.
I think it's time for a factory reset, which should fix the problem.


Re: You probably don't know the answer but what allows WiFi scanning anyway?
On 2017-03-20 04:53, Stijn De Jong wrote:

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My phone finds all SSIDs, but connects to none. If I tap on the home
ssid, it asks for the password (which it knows for sure).

Instead, I tap "more options", which displays the same list of SSIDs in
white background instead of black. There I switch off the WiFi, than on
again, and it instantly connects to my WiFi remembering its password.

This behaviour started about last November or December.

I also noticed that Bluetooth would not automatically connect to my car
hands-free device. It has started working again after I received a
security update about a week ago.

--  
Cheers,
       Carlos E.R.

Re: You probably don't know the answer but what allows WiFi scanning anyway?
On Mon, 20 Mar 2017 14:53:09 +0100, Carlos E. R. wrote:

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As I recall, my WiFi used to scan and show all the WiFi networks, and for
those that I tapped on, it would first ask for the password and then always
remember it from thence forward.

Now, it won't even scan, and yet, other apps (like Fritz WLAN) see the AP
SSIDs quite clearly, and, if I *connect* to the network once manually into
Android WiFi settings, then it remembers it from thence forward.

Funnily, if I don't connect, then it won't remember neither the SSID nor
the passphrase, which is odd to say the least.

Anyway, my next factory refresh should solve whatever setting it was that
screwed it up. I screw with Android settings often so this is just a nit in
the scheme of things. I just don't understand why as what Jeff noted is
good but I don't think it applied to my situation (which itself,
admittedly, is different than most since I screw with settings all the
time).

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