Monday, March 10, 2008

WiFi-a-Rama

I bought an old Linksys WRT54G router, and loaded the OpenWRT Linux firmware on it. Then I loaded the kismet package, hooked the Linksys up to a 12dBi omni antenna, and set the antenna outside the van (it's eventually getting mounted on the roof; this was the proof of concept). Kismet just ran, and discovered tons and tons of networks! And, it uses a prism0 interface, not the wl0 interface, in "repeater" mode, so that I can probe for networks and get online in client mode, both at the same time. So I've got WiFi in a huge way.

The LED's on this router are under software control in OpenWRT, through a shell script. Since I'll only be plugging in my laptop, I don't need LED's for each switch port to flash whenever there's traffic on a port. So my next step is to write a script that lights up more LED's whenever it discovers open (unencrypted) networks. And maybe blinks them when it sees traffic on them-- a LED version of the Kismet client UI. And then sit the thing on the dash as I drive around. So I can pick a spot to work based on how many open networks are around. Kind of like one of those handheld WiFi monitors but smarter-- this one will only show open networks (if someone has locked their door, I don't want in). Maybe flash a different special LED whenever it discovers the Free the Net mesh, which is my preferred way of connecting.

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