Well I have finally tried the ipw2100 Open Source driver and it works quite well. Here are the instructions for getting started on Gentoo, Linux:

1. First, in order to always get the latest version (including masked packages), I set an accept keyword in my /etc/portage/package.keywords You can simply create the file if it doesn't already exist. (This is the best way I have found to unmask an ebuild).

   # contents of /etc/portage/package.keywords
   
   net-wireless/ipw2100 ~x86

2. If you haven't in a while make sure your synced up with the latest portage tree.

   emerge sync

3. Install the software. If all goes well this will compile the kernel the module, and install the firmware from Intel.

   emerge ipw2100

4. Load the new module.

   modprobe ipw2100

   You should see something similar to the following in your /var/log/messages

   ipw2100: Intel(R) PRO/Wireless 2100 Network Driver, 0.51
   ipw2100: Copyright(c) 2003-2004 Intel Corporation
   ipw2100: 0000:02:02.0: Detected at mem: 0xC0204000-0xC0204FFF -> e0914000, irq: 11
   eth1: Bound to 0000:02:02.0

5. If you are connecting to a non WEP access point, then you should automatically associate on module load. You'll see the following in your /var/log/messages:

   eth1: Associated with 'apuwifi' at 11Mbps, channel 8

6. If you didn't have it already, you'll want to also emerge "wireless-tools" which you'll need to manage your connection.

   emerge wireless-tools

7. Use wireless-tools to set managed mode your wep key and essid

   iwconfig eth1 mode managed key YourSecretKey essid YourESSID

8. If you don't already have one, create a eth1 init script, then start it up to load the interface and get a dhcp address

   cp /etc/init.d/net.eth0 /etc/init.d/eth1
   
   /etc/init.d/net.eth1 restart

At this point you should be all set. I haven't looked into the slickest way to start and stop the wireless if your using WEP. I generally start the wireless with a simple shell script.

#!/bin/bash
modprobe ipw2100
iwconfig eth1 mode managed key YourSecretKey essid YourESSID
/etc/init.d/net.eth1 restart

I tested with the gentoo-dev-sources-2.6.7-r11 kernel on an IBM R40 Thinkpad. So far I have found less problems than with the Windows driver with the ndisloader. The driver also supposedly supports WPA which I haven't tested.

Resources

• http://ipw2100.sourceforge.net/ - Main Project Page
• Wireless configuration and startup - The Gentoo way, Gentoo Forums post with custom ebuild for handling wireless connections.
• Intel PRO/Wireless 2100 (IPW2100) mini DRIVER!!! - Gentoo Forums
• Intel Product Site

Update 2005-06-15: I am now using the WPA functionality, but have not written up instructions.

From the, "Its about time dept..."

Intel Releases Linux Driver For Centrino WLAN - Werner Heuser writes "Finally Intel has made their different announcements about Linux support for the WLAN part of the Centrino technology become true. Though not yet officially announced an Open-Source driver with included firmware is available at SourceForge. The driver is still experimental and supposed to work with 2.4 Kernels as well as with 2.6 ones."

I have been running the Windows driver via the linuxantNDIS Loader in Linux since I got my Thinkpad R40. I'll have to give the native driver a go, and see how it works.

Update: According to the Todo list, the driver doesn't yet support WEP. I will definately be sticking with the Linuxant driverloader while keeping an eye on this project. LinuxAnt even supports WPA so they are way ahead.