How to see who is using my WiFi

Question

I have a WiFi router at home and would like to know if there is any way to know who is connected to my WiFi network and using it. My WiFi network is password protected but still there could be a chance that neighbours crack it and could use my WiFi for free.

For this reason I would like to know is there is any tool to inspect the log of the WiFi router in order to know which computers are connecting to it.

Answer 1

Usually a WiFi router has a web interface that shows all (previously) connected WiFi devices... Try going to the IP address of your router through your browser.

Read this part, and the rest of my blog post about WiFi security here: http://blog.superuser.com/2011/03/28/iron-cladding-your-wi-fi-network/

Happy reading!

Answer 2

first, it helps to understand how WIFI works, read http://www.wi-fiplanet.com/tutorials/article.php/1447501 and/or http://www.cs.wright.edu/~pmateti/InternetSecurity/Lectures/WirelessHacks/Mateti-WirelessHacks.htm.

any other machine "using your network" has to be associated to your network which means it sends "associated beacons" (as explained here).

then all you have to do is to grab a tool which sniffs WIFI-packets and then analyze, which of the received packets are meant to be used "in your network", you can find a list of tools over at http://www.topbits.com/wi-fi-software-tools.html.

and then you can compare the MAC address of the sender with the MAC address of the devices you allow and hope, that the sender did not fake its MAC address :)

Answer 3

If you're worried, changing the password on a regular basis will ensure that if somebody does break in, they won't stay for long.

Obligatory XKCD reference: http://www.xkcd.com/341/

Answer 4

if you can use Linux, there is a tool which is called aireplay-ng it is actually a set u will find, airodump-ng,aireplay-ng and so on...

{For Linux only} if it is not downloaded and let's say you are using Ubuntu get the tool first using the apt-get install command,

then look for wireless routers iwlist scan wlan0

then see which channel you router is on,

then airmon-ng start wlan0

and finally airodump-ng mon0

Answer 5

as bloodphilia has said, you could find this you thorough the web interface of your point (typically 192.168.2.1 or 192.168.2.2, not always though). Mine at home will show the ip, mac and computer name so if there's a computer (or iphone, laptop, etc) you don't recognise you can set up a MAC Blacklist...or change you wireless key.

Answer 6

You can use Kismet to detect not only yours but any router which is transferring data. I usually use BackTrack for this purpose. But generally to hack modems wifi password.

Another alternative is to use Netscan which only works for windows. But you can detect any ip's using your modem. Also make sure wifi users are not isolated.

Answer 7

A GUI program is WifiGuard, free in Linux and Windows.

It can monitor and rescan the network every 1 to 60 minutes, play sound or send mail on detection, etc.

To use a CLI option for Linux, follow these instructions.