If you run a wireless network and Linux, Kismet is a tool you must have.

More than just a wireless sniffer, Kismet will let you list all access points in range and what channel they are running on. That's great information to have when you're deciding what channel to set your wireless access point to.

Configuring Kismet may seem a bit confusing at first, but there's really only one line you need to change in /etc/kismet/kismet.conf

source=iwl4965,wlan0,iwl4965

That's driver,device,name - I believe the name is arbitrary and can be set to anything, but I set mine to the same as the driver.

This line sets the source for packets. I found the iwl4965 (my wireless card driver) through a couple of steps.

Using the following command:

dmesg | grep Wireless

I was able to determine that I was running the Intel 4965 wireless chipset. From there, I simply looked on the Kismet website to find that iwl4965 was the correct driver name. Note I did not find this information in my lsmod results.

After adding the appropriate line to the /etc/kismet/kismet.conf file, simply run:

sudo kismet

That will start both the server and client and log the client into the server. While running, I was unable to do normal wireless activity, and actually had to reboot or use the wireless button on my laptop to cycle the wireless state before the wireless would work properly again.

Once Kismet has started, press "q" to close the help screen, arrow down to any access point and press "i" to get more information about the network.

Check the channels of all the other access points in range and make sure your access point won't conflict. The only channels that don't overlap are 1, 6 and 11. In my case, my two neighbors are using 1 and 6 so I chose 11.

Kismet can do much more than this, and is a great analysis tool. It will track rogue MAC addresses that are probing your network, allow you to integrate with WEP security programs and much more.

I had three more issues that occurred after upgrading from Ubuntu 8.04 to 8.10. First, it switched the sound system over to "pulseaudio" which broke the mic input and made audio output somewhat scratchy. I didn't realize this until I tried to use Skype. The solution:

sudo apt-get uninstall pulseaudio
sudo apt-get install esound
sudo reboot

I usually use an external mouse so I also didn't realize that the touchpad worked perfectly at the GDM login window, but after logging in it would stop and no amount of coaxing would bring it back. Turns out the upgrade disabled the checkbox under System + Preferences + Mouse + Touchpad. Just plug in a USB mouse and check that box again and the touchpad worked beautifully.

One last thing is that my changes to X to enable the media buttons on the side of the laptop no longer functions. I haven't found a solution to this one yet, but probably is related to the changes in the way X handles all the input devices.