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.

Friday, November 2, 2007

I Didn't Clear the CMOS - D'Oh!

At work this week a computer was hit by a power surge and it wouldn't come on, though the lights would light up. "Aha," I said, "I know just what to do!" I suspected that the power surge might have corrupted the CMOS memory. Back when I used to be in electronics class at Vo-Tech, I often ran into computers that appeared totally dead because of something as minor as a corrupt CMOS setting. They often had nothing major wrong with them once the CMOS was cleared.

I wasted no time in opening up the work computer that had been scrambled by the power surge, and I set the jumper to clear the CMOS. When the procedure was finished, the computer magically came back to life.

Later that day I got to thinking... Isn't it strange, I told myself, that the computer at work which I fixed by clearing the CMOS had exactly the same symptoms as my dead motherboard at home. For some reason, though I instantly knew to clear the CMOS on the work computer, when my home computer had had the same problem, it had not even occurred to me to check that!

My computer has been dead for a month while I struggled to find the time to set up a new motherboard and hard drive with it. I pulled my old motherboard out of the trash and set the jumper to clear the CMOS. I had already parted out all the pieces of the computer that the motherboard went in; I would feel like a fool if a 2 minute procedure could have saved that computer. "If this works, I'm won't know whether to be happy or pissed at myself."

I cleared the CMOS. The motherboard, which I had thrown away, the loss of which had thrown me off work and gaming for a month - the motherboard worked.