Use it to find out who is connected to your wireless router. There are plenty of reasons to worry about unknown people connecting:
1. Illegal downloads – if intruders download illegal content via your connection the police will come knocking at your door, not theirs. It may be very difficult to prove you were not responsible.
2. Internet Speed – the more people that use your connection, the slower your own internet speed will be.
3. Internet Usage – most ISPs set a limit on how much data you can download a month. If other people use your connection you might be cut off or have to pay more for the excess data.
4. Hackers – someone using your connection is already on the same network as you. This makes it easier to hack into your computer. Even without hacking, some shared folders on your computer may be available to all people on your network.
Wireless Network Watcher – A free program from NirSoft. It works on all versions of Windows from W2000 up to and including Windows 7.
For every computer or device that is connected to your network, the following information is displayed:
- IP Address – the internal network address of the device
- Device Name – name of computer or device (e.g. wireless printer) if available
- MAC address – unique identifier assigned to network hardware
- Network Adapter Company – manufacturer of the network hardware
- Device Information – easy reference to identify ‘Your Computer’ and ‘Your Router’
- First Detected (date and time)
- Detection Count – number of times detected
Tip: although designed for wireless networks, Wireless Net Watcher works equally well on wired networks – if used on a wired PC it will display wired as well as wireless devices.
How To Use Wireless Network Watcher
Download the program from Nirsoft at the bottom of the page here.
It’s available as a portable program in zip file format or as a standard program with install/uninstall support (a shortcut for running it will be automatically added into your start menu so it starts up with Windows). I’ll cover the portable version:
Unzip (extract) the zip file and run the WNetWatcher.exe program file to open the program.
The program automatically scans your network and builds a list of all wireless (and wired if on a wired PC) devices currently connected to your network as shown below:
Now you can easily find out who is connected to your wireless router.
If there is a device connected that you do not recognize, check it isn’t your own – remember that the list includes all connected devices in your home/office e.g. wireless printers, iPads, smartphones, internet TVs etc, not just computers.
If in doubt, turn your other devices off to remove them from the list and rescan to make it easier to find any intruders.
If you find an intruder on your network (e.g. the 192.168.0.10 Netbook in the above example is not a device in your home/office) you should improve the security of your wireless network to prevent future intrusion – see the guides on setting up a Cable or ADSL wireless router.
[In particular, make sure you use WPA2 security with a strong password and change the router’s default admin logon password. If an intruder has already changed the admin password to lock you out or you have forgotten it, you will have to reset the router and configure it from scratch.]
Obviously this scan only displays devices that are currently connected to your router – an intruder may not be connected now but could be in an hour’s time… Fortunately the program has the ability to do continuous background scans to detect future intruders:
In the Options menu tick ‘Background Scan’ as shown below:
A continuous background scan is now activated to discover when new devices are connected to your network.
If activating background scan so you can minimize the program and work on other things – it may also be a good idea to tick ‘Put Icon On Tray’ and ‘Tray Balloon On New Device’ and/or ‘Beep On New Device’ to display a popup message and/or make a beep when a new device is detected.
To avoid repeated notifications about your own devices whenever they are switched on, press F9 or choose Options \ Advanced Options and tick ‘Activate the beep … first time’ then press OK. Notifications will only appear the first time a device is connected.
Wireless Network Watcher is a simple and effective tool but the Background Scan feature makes it more than just a way to find out who is connected to your wireless router at a single point in time.
It can be used as an ongoing scan and alarm call to sniff out future intruders on your network.
That may be overkill if you already have a very well secured wireless router but, if you suspect an intruder (or are not sure about security), it could be worth doing.