ramblings of the village idiot

If anyone out there is looking for inexpensive colocation space in Minneapolis, I’ve got a half-rack at ipHouse which I’m using to host my gear, and am looking for other people who want 1U of space for $50/mo, including bandwidth (assuming fairly low usage). If you’re interested, give me a shout at colo at natecarlson dot com.

I’m afraid that I’m no longer able to offer colocation space in Minneapolis. In addition, I’ve had a lot of trouble finding providers that offer reasonable pricing for a 1U server with a modest amount of bandwidth.

I’ll include some quick reviews of companies I’ve either done business with or considered doing business with, all outside the Minneapolis metro area. If you sign up with any of these, I’d appreciate you letting me know that I sent you!

[continue reading…]

Well, what can I say, my new co-workers are finally kind-a-sorta rubbing off on my.. I’ve started one of these silly blog things. It’ll be interesting to see how interested I stay in this – care to place any bets? In any case, this is going to get “the green light” on my main page pretty quick, and I’ll expect to see some traffic shoved at it when that happens. Appreciate any comments!

[This page originally lived at http://www.natecarlson.com/linux/inspiron6000.php. I am working on migrating all content over to WordPress, which is why this post exists. Most of the comments on this post are waaay out of date.. if you still have an Inspiron 6000, any modern distribution should take care of you.]

This document contains some rough notes on what I needed to do to get Linux running smoothly on my Inspiron 6000.

Last modified: 9/13/05 Nate Carlson

I recently purchased a Dell Inspiron 6000, and of course am running Linux on it. The notebook has some “bleeding edge” hardware in it, so there is still some tweaking required to make things work properly.

First of all, some notes on installation. With Debian’s sarge rc3 installer, I had to use the 2.4 kernel, as the 2.6 kernel would not detect the CD-ROM. (The CD-ROM on this laptop is an ATAPI drive on a PIIX SATA bridge, and the SATA driver included with the 2.6 kernel does not support ATAPI-over-SATA.) When installing with 2.4, disk access will be s-l-o-w, because the 2.4 kernel does not support DMA with the chipset. Besides having to use a 2.4 kernel, you can install as usual.

After installation, you’ll want to upgrade to a 2.6 kernel. At first, whenever I enabled the ATAPI feature in the SATA driver, any heavy disk i/o would hang the system. I ran into a web site on the Inspiron 9300 that that has a patch to fix this behavior. You can grab the patch from:

http://www.rtr.ca/dell_i9300/

The patch on this site also includes patches to properly support the touchpad, which is very nice!.

If you have an Intel ipw2200 card, you will also want to install the wireless drivers. The driver is availabile in the ‘ipw2200-source’ package on Debian. Follow the directions to build and install; remember to grab the firmware image per the direction’s instructions.

My 6000 has an ATI Radeon X300 PCI-E video card. To get acceleration on this card, you will want the fglrx drivers from ATI. There are Debian packages for these drivers available from:

http://xoomer.virgilio.it/flavio.stanchina/debian/fglrx-installer.html

Again, just follow the directions to install. I am using Xorg from Ubuntu, so I used the Xorg packages.

If you have the Bluetooth module, installation is trivial – just make sure you have the Bluetooth USB drivers in your kernel, and it should work. The Bluetooth card shows up as a standard USB dongle.

Well, that’s it for now – I will try to organize this document better and include some more information at a later date. Hope it helps!

If you have any comments on this document, please feel free to drop me an e-mail at: natecars@natecarlson.com

[This page originally lived at http://www.natecarlson.com/linux/wireless-sniff.php. I am working on migrating all content over to WordPress, which is why this post exists. Most of the comments on this post are waaay out of date.. but the concepts are similar.]

This document describes how I got sniffing of 802.11b wireless networks working with my Linux box and a Prism2 wireless card.
Last modified: 10/01/01 Nate Carlson

Background:

We’ve been playing around with wireless networking at work, and one of the things I’ve been wanting to do is learn how to sniff networks for wireless packets, just to see what I can get. Hard part is all I have to work with for wireless cards are PrismII and Aironet cards, and the NetStumbler (for Windows) software only supports Orinoco. Of course, since I do the rest of my work in Linux anyways, I wanted to be able to sniff under Linux. So, I did some research, and it turns out that everything you need to do the sniffing is indeed available for Linux; it just hasn’t been well documented. So, here’s my attempt to document it! :)

First Step: Compile required PCMCIA packages

First step is to set up the PCMCIA stuff properly. You will need the following:

Standard PCMCIA Card Services package (you probably already have this)
Linux WLAN Package (provides full support for PrismII cards)
Patch to WLAN drivers to enable monitoring of packets (same patch you need for airsnort; this patch is integrated into linux-wlan-ng-0.1.10!)

Prismdump (dumps the packets from the wireless network into a PCAP file
CVS version of PCAP and TCPDUMP (current versions do not support 802.11b packets; CVS does)
Newest version of Ethereal (not strictly needed, but it lets you break down the packets for viewing

Download all the above packages, and compile and install according to the included directions (yeah, I might write a cheat sheet here eventually.) Make sure that you apply the patch to the linux-wlan package before compiling it (obvious). Note that depending what kind of PrismII card you have, you may need to modify the PCMCIA configuration to bind it to the PrismII card.

Second Step: Put the card into monitor mode, and sniff some packets

To put the card into monitor mode (note: this WILL make the network card unusable for normal traffic!), run the following command:

wlanctl-ng wlan0 lnxreq_wlansniff channel=N enable=true

Generally, you’ll want to sniff on Channel 6 (it’s the default, and most people don’t change the default), but you may want to play with other channels, too. To stop sniffing, run the same thing, except enable=false.

Once you have the card in sniffing mode, you can use prismdump to dump some packets out into a pcap-format file. This is really simple; just run:

prismdump > sniff.out

I generally also run airsnort’s capture with the ‘-c’ flag while I am doing this; that way, I can see how many packets have gone through. This file will grow, quick. Once it starts growing, it means you have some data!

Final Step: Analyze the packets!

Well, now that you have some packets saved to disk, I suppose you want to view them, huh? If all you want is the ESSID, and you don’t care about anything else, you can just dump the packets with tcpdump:

tcpdump -X -x -r sniff.out

Here is a sniff of one of my boxes doing a probe for AP’s:

11:38:09.496277 Probe Request (thisisessid) [ 11.0 Mbit]
0x0000   000b 7468 6973 6973 6573 7369 6401 0482        ..thisisessid..
0x0010   040b 16ff ffff ff                              .......

In the above, it’s easy to spot the essid: ‘thisisessid’. Not much else that’s very useful in this packet.

Here’s a Beacon packet from my AP at home:

03:33:58.788488 Beacon (abcdefghijkl) [ 11.0 Mbit] ESS CH: 6 , PRIVACY
0x0000   9a81 d49c 7700 0000 5000 1500 000c 7465        ....w...P.....ab
0x0010   6368 6e69 6361 6c69 7479 0104 8284 0b16        cdefghijkl......
0x0020   0301 0605 0400 0200 00ff ffff ff               .............

As you can see, Privacy (WEP) is invoked in this case, and the essid is ‘abcdefghijkl’. Fairly simple.

For even more information, such as the mac address, etc, you can load these packets into Ethereal by clicking File->Open, and loading the file. Note that for encrypted packets, I had to turn off the ‘Enable MAC name resolution’, ‘Enable network name resolution’, and ‘Enable transport name resolution’ options. Once you load up Ethereal, you can anaylze these packets just like any other packet — beyond what I want to document right now. :)

But, that’s the basics, I may add more details later.

If you have any comments on this document, please feel free to drop me an e-mail at: natecars@natecarlson.com

UPDATE: Sniffing networks on an AiroNet card

If you have an AiroNet card, it’s possible to sniff packets if you have a kernel > 2.4.7 and the CVS versions of libpcap and tcpdump. To do this:

# echo 'Mode: rfmon' > /proc/driver/aironet/eth0/Config
# tcpdump -i eth0 -w 

..and then load the file into Ethereal as usual.

[This page originally lived at http://www.natecarlson.com/linux/vaio-infrared.php. I am working on migrating all content over to WordPress, which is why this post exists. This is ancient, and probably no longer applies.]

This document describes how I got infrared working between my Sony VAIO PCG-F390 and my Nokia 8290 GSM Phone.
Last modified: 9/13/01 Nate Carlson

Background:
I’ve always wanted wireless internet, but didn’t want to pay the insane rates for Ricochet, etc. I finally ended up picking up a Nokia 8290 phone, which has an integrated modem that you can access over the infrared port. Set up under Windows was fairly simple (just download the ircomm updates, and away it goes), but I had some trouble getting it working under Linux. My two main problems were the broken serial port that the laptop sets up for the port, and then I had problems with latency that were caused by the kernel parameters I was using. I hope this document will make a similar set up easier for you. :)

First Step: Compile options into the kernel

I used the following options with kernel version 2.4.9-ac8:

CONFIG_IRDA=m
CONFIG_IRLAN=m
CONFIG_IRNET=m
CONFIG_IRCOMM=m
CONFIG_IRDA_ULTRA=y
CONFIG_IRDA_OPTIONS=y
CONFIG_IRDA_CACHE_LAST_LSAP=y

CONFIG_IRDA_FAST_RR=y
CONFIG_IRDA_DEBUG=y
CONFIG_IRTTY_SIR=m
CONFIG_IRPORT_SIR=m
CONFIG_NSC_FIR=m

Just make sure you have these options configured, and build as usual. Note that the CONFIG_IRDA_FAST_RR is very important; without it, you get extremely high latency on the link! I was getting ~5000ms pings over PPP once I brought the link up before I added that option; now I get around 1000.

Second Step: Set up the module config

pre-install nsc-ircc /bin/setserial /dev/ttyS2 irq 0 port 0 uart none
alias irda0 nsc-ircc
options nsc-ircc dongle_id=0x09 io=0x3e8 irq=10 dma=0

The setserial command disables the (broken) serial port for infrared that the notebook enables by default. If you don’t disable it, things aren’t going to work.

Third Step: Activate the Infrared Subsystem
Before you can activate the infrared devices under Linux, you will need to create the character devices (ie, serial ports) that you will use to connect to you infrared device. You only need to do this once. To create it:

# mknod /dev/ircomm0 c 161 0

# mknod /dev/ircomm1 c 161 1

If you need more than two serial devices, just increment the minor number.

Once you have the character devices ready, you’re ready to bring up the link. To do this, run:

# irattach irda0 -s 1

Once you have run this command, you should be able to snoop the traffic on the infrared port by using irdadump. You will always see traffic from your own computer, and if you have a device activated and in the line of sight, you should be able to see packets coming from that device.

Last Step: Use the port!

Once you see traffic from the other devices, you’re ready to go! Just point your favorite terminal program or ppp dialer to /dev/ircomm0, and you’re set. If you are using this to access your Nokia phone, you may also find applications such as ‘gnokii’ and the gsmutils package useful; they allow you to back up your phonebook, and do other interesting operations like that.

If you have any comments on this document, please feel free to drop me an e-mail at: natecars@natecarlson.com