Bad Wi-Fi Neighbors

Yesterday I finally got my new apartment hooked up with Time Warner Cable’s Road Runner Internet service. (While I was at it, I totally ditched TV and along with the quieter home, I’m looking forward to the nearly $40 savings on my bill each month!) The cable guy woke me up at noon and I answered the door in a t-shirt and boxers because I couldn’t find my pants. Oh well.

Anyway, he quickly set me up, left me extra cable wires at my request, and I started to set up my computer corner. Got my router hooked up after spoofing its MAC address, and started a cursory test of the Wi-Fi router’s signal around my apartment. Everything looked good for a while, so I moved on to more pressing matters, but later on in the day I began experiencing inexplicable network slow-downs and disconnects. I couldn’t make heads or tails of it until I launched NetStumbler and began exploring a little more in-depth.

(I had to do some quick research to gain any valuable information from NetStumbler’s findings, but luckily Wikipedia is perfect for this sort of thing.)

NetStumbler was able to locate 3 other wireless networks in addition to my own which were broadcasting through my apartment. The interference was remarkable. Each of them were transmitting in the mid-channel range from 3 through 6, and I was caught right in the middle. My network’s SNR decreased considerably the more I travelled away from the AP.

The thing about Wi-Fi is that the signals aren’t typically very strong to begin with becuase the coverage is intended to remain confined. This means that competing signals transmitted in close frequencies (termed channels) cancel each other out, causing the headaches my network was giving me.

Thanks to NetStumbler I knew what channels the other guys were using, so I started broadcasting at the other end of the spectrum and suddenly my reception was loud and clear all over the apartment, and I would guess wherever they are broadcasting from too. The lesson in radio technology and Wi-Fi in general was extremely interesting and informative, but on a more practical note this is about being a good Wi-Fi neighbor and not competing for signal strength on the same channels.

It also brings up some very critical concerns involving security and privacy issues. One of the networks NetStumbler found was an unsecured Linksys-based AP. The owner probably doesn’t realize that his home computer network is wide open to anyone with a wireless networking card and a computer, but it is. Since Wi-Fi works on radio technology, and radio can pass through solid objects like walls, the area covered by his transmitter pokes out of the confines of his apartment.

If I were the bad neighbor, I could use his Internet connection, or even browse his iTunes music collection and he would probably be none the wiser. If he had a wireless web cam hooked up to the network, I could see whatever images it broadcasted too. And I wouldn’t even have to start hacking. That’s why it’s so important that you take the steps to protect your wireless network with something like WPA or WEP.

WEP is not very strong, and the new generation of WEP-cracking tools can break it in a matter of minutes, so it should never be considered a preventative measure to keep crackers out of your network. Rather, it is a detterant that should be used to dissuade crackers from trying. My old router only supports WEP encryption on its WLAN so that’s what I’m stuck with, but the fact that this other guy keeps his network wide open means I feel pretty safe here.

Afterall, which house do you think a burglar would break in to? The one with the big security-company sticker on all the windows and doors and the lights on, or the one in the dark with the open window and unlocked door?