Kismet sounds to be a nice tool for Wi-Fi diagnostics. Port installation can be easily done via:

cd /usr/ports/net-mgmt/kismet && make install clean

Within newly installed /usr/local/etc/kismet.conf, one needs to enable particular packet sources, Wi-Fi channels and a user, to which kismet(1) with setuid(2):

suiduser = <your user here>

[...]

source=radiotap_bsd_ab,wlan0,bsd

[...]
sourcechannels=radiotap_bsd_ab:1,6,11,2,7,3,8,4,9,5,10

In order to make kismet text-based CLI to work, one needs to enable DBUS. It should be already installed in your system. Enabling means inserting particular line into your /etc/rc.conf file:

dbus_enable="yes"

In order to start working with wlan0 interface which we have mentioned as a available packet source, we need to create it. This step is different from creating WLAN interface in default mode – we need to create interface working in “monitor mode”:

ifconfig wlan create wlandev bwi0 wlanmode monitor

for Broadcom-based card, or:

ifconfig wlan create wlandev ath0 wlanmode monitor

for Atheros-based card.

This is basically the end of the setup procedure. You can start Kismet right now.

Let me know if this short tutorial has some flaws:

Wojciech A. Koszek

wkoszek@FreeBSD.org