Use these two powerful Linux tools to map out the locations of Wi-Fi networks.
GPSd [Hack #20] is a great tool to get data from your GPS receiver. You can make it even more powerful by combining it with Kismet [Hack #29], allowing you to physically map locations of wireless networks.
In order to make this work, you will need to have both GPSd and Kismet installed and functioning with your Linux system. Consult the hacks on both pieces of software if you have setup questions.
If you plan to do some network mapping with Kismet, keep the following in mind:
Above all, when you are driving a car, your first responsibility is to drive safely. Pay attention to the road and drive carefully.
To begin mapping networks with Kismet and GPSd, take the following steps:
$ sudo modprobe pl2303 $ dmesg | grep tty ttyS00 at 0x03f8 (irq = 4) is a 16550A ttyS02 at 0x03e8 (irq = 4) is a 16550A usbserial.c:PL-2303converternowattachedtottyUSB0(orusb/tts/0for devfs)
$ sudo gpsd -D9 -p /dev/ttyUSB0 -s 4800 Telnet to GPSd and use p until you have a reliable fix, then disconnect when you are done: $telnet localhost 2947 Trying 127.0.0.1… Connected to debian. Escape character is '^]'. p GPSD,P=0.000000 0.000000 p GPSD,P=41.485882 -71.524841 ^] telnet>q Connection closed.
$ sudo kismet -g localhost:2947
When you shut Kismet down, it writes out logfiles. Check the logtemplate setting in kismet.conf to see where it puts its log files; for example:
Kismet writes several logfiles in the logtemplate directory (in the following filenames, I starts at 1 and increments each time you run Kismet on a given day):
Kismet log in semicolon-separated fields, one line per entry. The first entry contains the field names.
Kismet log in a pcap(3) format suitable for loading under Ethereal (http://www.ethereal.com).
Kismet log in a format designed to be read by the gpsmap utility, which is included with the Kismet distribution.
A human-readable dump of the networks that Kismet encountered.
Kismet log in an XML format.
To generate a map, run gpsmap on the .gpslog file. See the gpsmap manpage for all the drawing and mapping options. If you choose to use a downloaded map (the default), you must be online. Figure 1-60 shows a map generated by the following command:
$ gpsmap -S3 -p /var/log/kismet/Kismet-Feb-16-2004-5.gps
Figure 1-60. Wi-Fi power levels in the Kingston, Rhode Island area
The -S option specifies which map server to use:
If you have trouble with one of these map servers, try another (Tiger is loosely maintained by the Census Bureau and is not up 100% of the time). Use -p to show power levels or -e to simply plot the locations of the hotspots on the map (see the gpsmap manpage for more options).
1.23.1. See Also
Bluetooth, Mobile Phones, and GPS
Network Discovery and Monitoring
Wireless Network Design
Appendix A. Wireless Standards
Appendix B. Wireless Hardware Guide