Stories about Software


Old Linux Computer with new Wireless Encryption

As I’ve previously mentioned, one of the things that I spend a good bit of time doing is home automation. For prototyping, I have a bunch of very old computers that I’ve acquired for free. These are scattered around the house (much to the dismay of anyone with a sense of decor) and I use them as dumb terminals for interfacing with the home automation system. That is, I have a client/server setup, and these guys put the “thin” in thin-client.

Now, because many of these were made in the 90s, I don’t exactly put Windows 7 (or even Windows XP) on them. Most of them range between 64 and 256 megs of RAM and are of the P-series intel processors from that era. So, the natural choice is Linux. I have had luck using Damn Small Linux (DSL), TinyCore linux, Slackware, and Ubuntu. Since most of these are not for the faint of heart or anyone who isn’t comfortable editing low level configuration files in pico or VI, I’ll focus this post on Ubuntu (more specifically, Xubuntu, since the standard windows manager is a little much for these machines).

Because of the nature of what I’m doing–allowing machines on my network to control things in the house like lights and temperature–network security is not a convenience. It has to be there, it has to be close to bulletproof, and I can’t simply say “the heck with it — I’ll compromise a little on the settings to make configuration easier.” So I use a WPA-PSK encryption scheme with a non-broadcasting network.

Now, my house has three stories including the basement, and while I enjoy home improvement, I’m not such a glutton for punishment that I’ve retrofitted cat-5 connections in every room. Getting these old Linux machines connecting to the network is an interesting problem that I’ve ultimately solved by buying a series of Belkin wireless USB dongles. For the most part, these old computers do have a couple of USB jacks. So what I’ll document is how I’ve had success setting up the networking.

The first thing I do after installing the Xubuntu OS is to go to my main office computer and download ndiswrapper. This link is helpful, as it points you to where you can go about downloading the debian package to install from the command line: Ndiswrapper.. Ubuntu OS generally assumes for the purpose of their package manager (which, as an aside, makes me smile every time someone says that the Android/Apple walled app garden is a newfangled concept) that you have an internet connection or that the CD has the packages that you need. If I had the former, this post would be moot, and the nature of the slimmed-down Xubuntu install precludes the latter.

So, you can find the version for which you need ndiswrapper and grab it from the mirrors. From there, you can install the packages by following the instructions at the link for using dpkg from the command line. After doing so, you will be equipped with everything you need from ndiswrapper. Ndiswrapper is a cool little utility that essentially inserts a logical layer between the drivers and Linux, thus allowing Linux to use Windows drivers as if they were native to that OS. The FOSS folks are generally cool this way — no one writes anything with Linux in mind, so they bend over backwards to be compatible.

Once you have ndiswrapper installed, the next thing to do is to grab the CD that came with the Belkin dongle and pop it into the Linux machine. Mount the CD (if it doesn’t automount — I tend to do all this from TTY4 rather than the UI because when you only have a few hundred meg of RAM, the UI is a little slow) and navigate to the folder containing the .INF file. If you’re doing anything like I am, this is going to be inside of a folder with a name like WinXP2000. The key thing here is to be sure that you find the driver that matches your processor architecture — probably i386. This can easily be accomplished if you know what version of Windows came installed on the machine before you wiped it to put Linux on. If the machine didn’t initially come with Windows, you probably know what you’re doing anyway.

From here, you can execute a “sudo ndiswrapper -i {yourfile}.inf”. This will install the driver in the configurables of the ndiswrapper utility and ndiswrapper should take care of loading it on your next and any subsequent reboots. While you’re at it, you may as well reboot now and get the driver loading. If you’re feeling intrepid, you can try restarting the networking service to see if you start to connect, but I make no guarantees that this will work.

Once you’ve rebooted, Linux should recognize the driver, but you won’t be connecting to your network. I’m not sure off the top what it loads for default settings, but it sure isn’t a requester configured for encrypted access to your network. So now, I edit my /etc/network/interfaces file to look like the following:

auto lo
iface lo inet loopback

auto wlan0
iface wlan0 inet static
address {machine's IP address}
gateway {router's IP address}
dns-namesevers {dns -- probably your router's IP again}
wpa-driver wext
wpa-ssid {network SSID}
wpa-ap-scan 2
wpa-proto WPA RSN
wpa-pairwise TKIP CCMP
wpa-group TKIP CCMP
wpa-key-mgmt WPA-PSK
wpa-psk {connection key}

If you fill in your own info for the {}, you should be set to go. This will configure you as a supplicant (connecting client) to a network with WPA/PSK, static rather than DHCP addresses, and non-broadcasting status (though this doesn’t really matter on Linux — iwlist, the linux utility, sees networks whether or not they broadcast). And, best of all, it will do all of this when you boot since it’s part of the interfaces file. No adding things to rc.local or your login script like in the old days.

The only extra thing here is generating your PSK. That is a little beyond the scope of what I’m explaining here, but if there is some interest in the comments for this post, I can create a follow up explaining how to do that.

I’m not sure how many people are fellow enthusiasts of re-appropriating old clunker machines to do cool, new things, but I hope this helps someone, as these sorts of configuration issues can be maddening.