WiFi on a PC

April 17, 2018 at 07:56:28
Specs: several
I'm pretty sure I asked this before, but didn't get a real answer ...

I connect my Windows 10 HP laptop to the Internet via WiFi
through a separate modem/router. If I leave the modem/router
turned off, but turn the laptop's WiFi on, could a hacker with
the right tools detect a WiFi signal from the laptop? Or does
the laptop only send out a Wifi signal either when directed to
by a program in the laptop, or in response to a WiFi hotspot
that it is already connected to?

In other words, I'm asking whether the laptop broadcasts a
WiFi signal all the time when WiFi is turned on.

-- Jeff, in Minneapolis


See More: WiFi on a PC

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#1
April 17, 2018 at 08:31:40
The laptop will be emitting a WiFi signal all the time that the it (or, at least, the WiFi card) is turned on. Most laptops have a switch (hardware or software) allowing the WiFi card to be disabled.

But, as far as I know, a hacker would not be able to connect to your computer unless it was set up as an ad-hoc network (which it won't be). A WiFi connection is only one way that a computer can, in theory, be viewed remotely. If you are paranoid, never use a computer for anything private other than in a clean room. Fortunately, most of us are not paranoid.


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#2
April 17, 2018 at 09:15:02

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#3
April 17, 2018 at 11:25:00
Do you know why/what the laptop would be emitting?
It seems completely unnecessary, and just creates an
avoidable opportunity for creating radio interference.
As I see see it, the laptop only needs to emit when it
is sending data or is responding to a signal from the
hotspot selected by the user.

-- Jeff, in Minneapolis


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Related Solutions

#4
April 17, 2018 at 11:40:05
Do you have a little manual on/off switch for the wifi on your laptop? If you do, simply shut it off when not in use. Problem solved.

As to your last question.......It's along the same lines as why a wired network interface is lit up, even if it's not in use. The point being, it (be it a wired or wireless network connection) is ready to be used at any given moment and is broadcasting that availability.

Typically this is a "keepalive" type packet.

It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.

***William Henley***

message edited by Curt R


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#5
April 17, 2018 at 12:27:57
A "keep alive" signal doesn't seem to make sense. If the
laptop WiFi is turned on, it detects WiFi hotspots nearby.
If any of those hotspots is one it has been connected to
previously, it will reply to the signal from that hotspot and
negotiate a new connection. It might then occasionally
transmit a keep alive signal, but it wouldn't need to do so
more than once every few minutes. Or it could just reply
to the hotspot whenever the hotspot wonders if the laptop
wants to keep the connection alive. If the laptop does not
detect a hotspot that it has connected to before, then it has
no reason to transmit anything at all. It should just keep
listening.

-- Jeff, in Minneapolis


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#6
April 17, 2018 at 13:16:19
If you're convinced that the network card transmits nothing when not connected to a network, then you have nothing to worry about.

Actually, you have nothing to worry about anyway.


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#7
April 17, 2018 at 14:50:35
Simplest is to switch off wifi on the computer when not in use? Removes any possibility of whatever???

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#8
April 17, 2018 at 15:48:30
If the laptop does not detect a hotspot that it has connected to before, then it has no reason
to transmit anything at all. It should just keep listening

You might think but no. It's listening and asking if there are any available networks it can connect to. But either way, you really don't have to worry and if you can't help it, then shut the wifi off. If you don't have a manual on/off switch on the device, then you can just disable the wifi network interface in "Network and Sharing Center >> Change Adapter Settings" (Right click on said adapter and select "disable")

It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.

***William Henley***


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#9
April 17, 2018 at 16:08:43
Curt R said:

> It's listening and asking if there are any available networks it can connect to.

Why?

The modem/router is listening and telling everyone it is a network that
can be connected to. Any computer listening can try to connect to it.
There is no need for any computer ever to ask if there is an available
network it can connect to. It gets the list of available networks just by
listening. It doesn't have to ask.

Why does it ask?

-- Jeff, in Minneapolis


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#10
April 17, 2018 at 17:06:08
Why does it ask...?

Possibly that’s just the way the system was designed way back when? The presumption being that if a wifi device is active (as in powered up and ready to communicate) then it will want/require wifi access points to connect with and thus “communicate/chat etc.”. Soit goes a huntng, lookng etc...

When a computer or similar seeks to connect to a wifi router, it must request permission - as in provide a valid pass key/access key - and having given the correct details then it can connect to the router. If it can’t or doesn’t give correct details then no can connect; and thus will go looky elsewhere...

It is nonetheless an interesting question, and likely not all that many ever bother or think about the reason why etc.; moi included. Most of us just take it for granted, accept that that’s the way it is. So a fair question “Grasshopper”...

George Bernard Shaw likely would ask “why not”, rather than “why”? He had a habit of asking “why not...” as it was the less common, conventional approach; and apperently he was somewhat unconventional..


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#11
April 17, 2018 at 17:42:41
All I have been able to imagine is that either it was designed that way
in order to be more complex so it would cost more and thus provide a
greater profit potential, or you are mistaken that the computer asks if
there are available networks.

-- Jeff, in Minneapolis


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#12
April 17, 2018 at 21:15:36
Round and round we go..... never to stop.
As suggested, either don't worry about it or turn it off when not in use.
There is no real thing here to worry about but you cannot redesign the entire Wifi protocols unless you get a much stronger education on it and then are able to come up with something better.
So ignore it or disable it.... Or hard wire it and disable the Wifi when using it at home.

You have to be a little bit crazy to keep you from going insane.


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#13
April 18, 2018 at 00:00:33
Jeff

If you're still not convinced, read this link which explains how WiFi clients discover access points by use of Probe Request packets.

https://mrncciew.com/2014/10/27/cwa...


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#14
April 18, 2018 at 06:34:45
Try Acrylic WiFi scanner. It will detect ALL the wifi signals in your area & provide MAC address, channel, connection speed, type of security (WEP, WPA, WPA2), make/model of router, etc.

https://www.acrylicwifi.com/en/wlan...

https://www.acrylicwifi.com/wp-cont...


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#15
April 18, 2018 at 09:49:35
Thanks for the suggestion of 'Acrylic'. I'll be very interested
to learn what it finds my computer is transmitting when not
connected to the modem/router.

The link to the technical info doesn't really explain very much.
It obviously was written by someone whose first language was
not English. The article begins:

> Discovering the network by scanning all possible channels &
> listening to beacons is not considered to be very efficient.

Can you explain why it isn't considered to be very efficient?

> To enhance this discovery process, stations often use what
> is called active scanning.

Which appears to mean that every WiFi device transmits a
signal received by every other WiFi device within range, and
that each of them has to determine whether each signal it
detects is coming from an access point or a client device.
My computer detects more than 60 access points, including
those in the apartment above mine, the apartment two floors
below mine, the apartment next to that one, the business next
door to this building, one across the street, and something on
the opposite side of the block. I presume that a comparable
number of client devices are detected but not shown in the list.
All of the access points-- including my modem/router-- must be
detecting and analyzing all those same signals, and responding
to all of the client devices. All of those responses must then be
received and analyzed by all of the client devices, continuously.
Sounds real efficient.

-- Jeff, in Minneapolis


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#16
April 18, 2018 at 11:47:21
We seem to be back to "I don't believe that my WiFi card sends packets when it's not connected to an access point".

Fine - you have nothing to worry about and we can stop trying to convince you.


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#17
April 18, 2018 at 13:48:19
This isn't (or shouldn't be) a difficult concept to grasp. If the wifi adapter on your laptop is enabled, it's constantly probing the airwaves for a connection. That's it's job - to transmit & receive - that's what it does, that's all it does! EXPLANATION

RE #14: I posted it to fuel your paranoia.


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#18
April 20, 2018 at 03:33:23
riider wrote:

> This isn't (or shouldn't be) a difficult concept to grasp.
> If the wifi adapter on your laptop is enabled, it's constantly
> probing the airwaves for a connection.

It should listen constantly, but why would it also transmit
constantly? That seems redundant and counterproductive.
It would enormously increase the amount of radio traffic
required to make a connection. As I understand it, instead
of just listening for access points and responding to the
one the device is set up to connect to, it does that plus it
constantly sends a message to every other device within
range, and all those other devices constantly receive the
message, interpret it, and respond to it. Then the devices
all have to receive the responses and interpret them.

There is no apparent reason to do any of that. The article
suggests that it is intended to improve efficiency, but it
doesn't say how efficiency is improved. It is apparent
that it would make the system considerably less efficient.

-- Jeff, in Minneapolis


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#19
April 20, 2018 at 04:02:44
The system was designed that way back in the dark ages, when we weren't as concerned about security and hacking etc. as now... Also remember that a lot of kit was designed with research, scientific, academic and military in mind - consumer and business came on board later...

Military types (and ham radio operators too) often broadcast a "CQ CQ" signal to say thery're out there and ready or waiting to chat... (Broad Sword calling Danny Boy...; ET calling home...)

Possibly efficiency increase - have to admit I'm not sure I follow that aspect. Possibly it suggests that if another computer (A) was looking for a given computer (B) over a wifi link, and that B was saying in effect "I'm over here" and this is my address... then A would find and go to it faster than if it A - had to in effect say "where H.. are you", or go a hunting...

Udderwyze...????


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#20
April 20, 2018 at 04:18:51
Consider a commercial location, say your work, a large hotel, A sprawling factory, etc. that uses multiple access points and you maybe roaming around it (maybe with a tablet instead of a laptop), the network can keep track of where you are to efficiently direct traffic to you and even use multiple antennas on an access point to shape the Wifi signal to 'follow' you for better reception. In a well set up network this can and does happen. Similarly, even with your non-commercial router or access point, your distance and direction to the antennas has your access point trying to optimize your connection within its capabilities so when you need to send or receive a 'real' packet it can get through.
I know some of this because I recently researched and set up a multiple access point Wifi network at work where the old network had poor coverage. Now the overlapping coverage of all of the access points creates a seamless Wifi network that works.

You are going to have to decide to either trust the system that is in place to make it work as 'everywhere' as possible or shut off your Wifi and Wifi network card and either use network cables or turn it on as needed (too annoying as far as I am concerned) only.

You have to be a little bit crazy to keep you from going insane.


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#21
April 21, 2018 at 08:33:45
trvlr wrote:

> Possibly it suggests that if another computer (A) was looking
> for a given computer (B) over a wifi link, and that B was saying
> in effect "I'm over here" and this is my address... then A would
> find and go to it faster than if it A - had to in effect say
> "where H.. are you", or go a hunting...

The method that you suggest is less efficient appears to be more
like the method that the article ijack linked to implies improves
efficiency! That's how it looks to me, assuming that Curt R
correctly described the computer (in reply #8) as constantly
"asking if there are any available networks it can connect to."

You guys seem to be telling me that all access points constantly
broadcast who they are, listen for requests from devices to make a
connection, AND listen for and respond to requests for information.
Until a connection is made, all client devices constantly listen for
the access point broadcasts, broadcast requests for information,
and listen for replies to those requests. Each time a device sends
a request for information, ALL the access points within range on
that channel reply, and ALL the client devices hear the reply.
ALL the client devices have to interpret ALL the replies they hear
in order to determine whether the reply is from the access point
they want to connect to or are already connected to.

Client devices broadcasting requests for information would be a
resonable way to start a connection, but access points already
broadcast the info required, so client devices don't need to.

-- Jeff, in Minneapolis

message edited by Jeff Root


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#22
April 21, 2018 at 08:56:55
Fingers,

It sounds like you are suggesting that WiFi works pretty much
the same as cell phones: Every phone constantly broadcasts.
There may be tens of thousands of phones in each cell, with
the signal from each phone continuously received by maybe
five to ten towers. The central control system decides which
channels to use from which towers for each phone.

-- Jeff, in Minneapolis


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#23
April 21, 2018 at 13:57:42
You have a few points wrong.

Access points don't necessarily advertise themselves - they certainly don't broadcast all information.

Requests for information from clients isn't continuous. It can be as seldom as once a second or less - an eon in computer terms.

Requests aren't necessarily responded to by all access points. The request may be for information about a specific access point, or only two or three. For example, my mobile devices know that of all the access points in my neighbourhood I only ever connect to the one in my home. And they know which channel I use. They don't need to query details from other access points in the vicinity.

If you want to understand these things - or at least discover what happens - you would do better to consult the appropriate RFCs rather than arguing on a forum. Networking, and networking protocols, are a little more involved than you imply. Network communications are always two-way afairs, with requests, acknolgements, data, etc. all being transmitted. There is no such thing as just listening on a network; if a NIC is listening for incoming packets it is also transmitting outgoing packets if only acknolegements to synchronise communications.


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#24
April 23, 2018 at 07:06:16
Rather than debate whether it makes sense or not in here Jeff you should seriously consider doing some reading/research on your own and find out definitively the whys and hows of how it all works.

We, the helpers in this forum, did not invent/create/build any kind of wired, or wireless devices so debating the sense and logic of how they behave with us is moot. If you're not happy with it, either get in contact with the people who do, or, become a computer engineer and build them the way you think they should be.

But, I would suspect the people who do build these devices and given a lot of thought as to how to have them behave and how they do presently is the end result of not only that thought, but likely also a lot of trial and error.

It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.

***William Henley***


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