Re: Remote monitoring of interference?



"dgeesaman@xxxxxxxxx" <dgeesaman@xxxxxxxxx> hath wroth:

Phew, it's been a long time since I've compiled a unix tar. I'd need
a whole other computer to run this and sit there collecting data,
correct?
Dave

Nope. What you need is a "LiveCD". It boots Linux and runs Kismet.
My favorite is:
<http://www.remote-exploit.org/backtrack.html>
Be sure that the wireless device in the monitor PC is supports. You
can do remote control of sorts with VNC.

However, I think you're wasting your time trying to setup a remote
monitoring station. Kismet will show much more than the typical
Windoze wireless sniffer (Netstumbler) because it will show access
points that hide their SSID and client radios. That's fine if you
expect interference from wi-fi networks, but useless for non-802.11
sources. See list at:
<http://wireless.wikia.com/wiki/Wi-Fi#Interference>

Kismet can be operated remotely as resident inside a WRT54G type
wireless router. No computah required. See "Kismet Drone" or "Kismet
Server":
<http://www.dd-wrt.com/wiki/index.php/Kismet_Server/Drone>
There are several ways to install, configure, and operate a remote
monitor, so please RTFM before attacking. I have several of these
installed (monitoring convention hall usage). However, they are
useless for non-802.11 interference sources.

You might have better luck with a spectrum analyzer. I use several
including the original version of WiSpy:
<http://metageek.net>
I've never tried to operate it by remote control.

The problem here is that the original version is rather deaf and can't
really pickup weak sources of interference. For that, you'll need
either the current model, or a real HP or Tektronix spectrum analyzer.
The cheapest I've found that's usable is a Tektronix 492 which
typically goes for about $1,500.

I'm not sure what to suggest. It's difficult enough to find an
interference source in person. Doing it by remote control might be
impossible. I've never tried it. What I usually end up doing is
borrowing a spectrum analyzer, connecting it to the most directional
antenna I can find (i.e. grid dish), and play transmitter hunt. Even
that's not guaranteed.

My most effective indoor method is just a laptop and ping. I run
continuous ping to the access point and walk around. As I get closer
and closer to the source of interference, the latency and packet loss
both increase. Sitting the laptop next to an operational 2.4GHz
cordless phone usually drops the connection. (Note: interference can
enter at both the client and the access point ends of a wireless
link).

Other methods are to simply monitor the interference and look for a
pattern. I had one problem that would only appear erratically at
around lunch time. At lunchtime, the entire building wireless network
would completely die. After lunch, it would recover. After 3 months
of head scratching, someone else traced it to the worlds most leaky
(and filthy) microwave oven on the noontime lunch truck.

Good luck.

--
Jeff Liebermann jeffl@xxxxxxxxxx
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
.