Thursday, November 8, 2007

Wifi Combat

I suspect someone has been jamming my wireless network today.

I noticed that web pages were taking a long time to load, which is strange since my cable internet is normally very fast. Then my laptop's wireless connection to my router
started dropping out within seconds every time it reconnected.

I opened my site monitor and found that new non-broadcasting wireless networks were suddenly popping up on channels 1 and 11, and the strongest one was on the same channel as my router. Though my connection kept dropping out, I managed to connect to the admin page on my router long enough to move it to channel 6. It's not a good idea to use the wireless network to do router configuration, but I wasn't too worried about someone spying on my router password out of my packets because I run WPA-2 encryption.

After I moved to 6, someone opened a new nonbroadcasting network on channel 8! Usually, 1-6-11 are the three channels used. These are chosen because they are as far apart as you can get; the intermediate channels interfere slightly with each other. It is possible that someone might choose 8 knowing that it would interfere with my 6. I thought, "they're trying to squeeze me out."

Haha, they don't know who they're messing with. I went into my router again and this time I sliced my broadcast power down as low as it would go: 3 percent.

You might think, that if you are in a wifi jamming war, you would want to make your signal as strong as possible. That's brute force thinking. The Zen way to beat them is to make it so they don't know your signal is there at all. A signal that is too strong is a common security risk for wifi networks; if you instead use only the minimum signal you can get by with, you reduce the chances of someone eavesdropping on your signal from far away. By setting my broadcast signal so low, hardly any of it spills outside the walls of my house.

Once I had the signal turned down so that my jammer couldn't see my network, I switched channels one last time - from 6 down to 5, so that it would both be farter from 8, and odd instead of even (if that matters -?). Though my 3% signal only gets two bars on my meter, it still runs at the full 54 MBps, and I haven't been knocked offline since.
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