WiFi running a bit slow lately? If your router is still using old security methods such as WEP, then there’s a very real possibility that someone has hacked in to steal your WiFi. In my article on Cool WiFi Devices You’ve Probably Never Heard Of, I showed you a $100 commercially available router that would automatically hack your WEP-protected WiFi network in less than half an hour. Apart from the obvious fact that your internet will be slower, the hacker might be using your internet to do nefarious evil things – all of which could easily be traced back to you. So how you can find out if someone is using your WiFi, and perhaps more importantly – what exactly can you do about it?

Check the devices associated with your router

This method is 100% guaranteed to see any devices registered on your network, but not every router contains this valuable info. Log in to your router by typing it’s IP address directly into the browser address bar. In most setups, either http://192.168.0.1 or http://192.168.1.1 should work, or it may be written on the router itself, along with the username and password you need to log in with. If you can’t find a password anywhere, and don’t remember changing it, then check the database of default passwords here, or phone your ISP (assuming they gave you the device).

Once logged in, look around a section called Attached Devices or Device List. On DD-WRT flashed routers, this is under the Status -> Wireless screen. You will find a list of all the IP addresses currently being used.

On my standard Virgin Media router, I found a list under the IP filtering section.

Of course, not all your devices will have helpful names, so you’ll need to figure out the IP address of each computer and WiFi device you own in order to cross-check them against the list. I covered how to find your IP address a few days ago when I showed you how to control your torrent client from your mobile. Don’t forget that an iPhone or Android phone will also have it’s own IP address if it’s using your WiFi, so you’ll need to account for those too.
Track Them Down Physically

This may be taking it a little far, but running the MoocherHunter live CD tracking suite will enable you physically hunt them down by triangulating network signals. Scary stuff, indeed. You’ll a directional antenna for this to work best.
What to do about it
Basic Security – Stop using WEP

Any router purchased in the last 5 years or so should be able to support a more secure authentication protocol, so log in to your router again and find the Wireless Settings screen.

Change the security options to either WPA or WPA2. WPA2 is more secure, but I find it’s incompatible with some of the devices on my network so I chose the option that allows for both. Don’t choose the Enterprise option as it is designed for companies with authentication servers. When choosing your password, make sure it is at least 15 characters long, includes upper and lower case letters, numbers, and punctuation.

There are some other methods that people will typically advise you to take, but put simply – they don’t work:

Hiding your SSID: You can hide your network name so it won’t be seen, but freely available hacking tools such as Backtrack will reveal them instantly.

IP filtering: This blocks out a specific IP, but changing IP is as simple as refreshing the connection.

MAC filtering: More secure since it blocks a device via the unique hardware address that is given out when it’s manufactured, but again, anyone trying to steal your WiFi can easily “spoof” their MAC address.
Funny – Turn their internet upside down

For anyone with a spare PC or who doesn’t mind messing with the command line, you could create an open WiFi network specifically for these freeloaders, and run everything through a Linux proxy. The proxy can setup to cut directly into their internet stream, and one interesting outcome is that you can turn all their images upside down.

Profit – Run a paid WiFi portal

If you install the open source DD-WRT, you can run a paid WiFi Hotspot portal. Set your own rates, never worry about payment processing (they handle everything), then just collect your check if someone has used your hotspot – you’ll get 75% of the money paid. Remember, you’ll need to live in a big city for this to be viable with lots of potential customers. I’ll look at this option more at a later date to show you exactly how you can set one up if you’re interested.

Conclusion:

So your WiFi is feeling a little sluggish? The truth is that someone probably isn’t stealing your WiFi. More likely your computer is running slowly, or your router needs rebooting. You could also try boosting the WiFi signal.

Oh, and let us know in the comments if you’ve found people stealing your WiFi before, or have any amusing WiFi stories to tell.