Go WiFi with Linux

If you have a notebook with a shining sticker boasting of Intel Centrino Mobile Technology and if your notebook is up and running on Linux, read on. What is Centrino? In a nutshell, it is a combo of an Intel Pentium processor, a specific chipset and integrated wireless capability. If you want to dwell into further details refer to
www.pcquest.com/content/topstories/wireless/103081104.asp. 

As apparent, the most exciting part of the Centrino technology is the integrated WiFi. Setting it up is a breeze if you are
running Windows, all notebooks ship with the Windows drivers. But when it comes to Linux, it will take you the length of this
article to set it up. 

Windows drivers for Linux

Say hi to NdisWrapper project (http://ndiswrapper.sourceforge.net). With NdisWrapper, you can use the Windows drivers for a network card, which you would otherwise dump for
Linux. 

Many network cards whose drivers are not available for Linux can work using the NdisWrapper package, and Centrino's WiFi is one of them. In this article, we will set up this package on PCQLinux 2004 (given out with the March 2004 issue of
PCQuest). 

First ensure that you indeed have the Centrino WiFi that we are talking about. This article has been written using an Intel PRO/Wireless LAN 2100. To confirm if you also have the same, issue the following command:

lspci

If the output contains something as follows:

Network controller: Intel Corp. PRO/Wireless LAN 2100

then we are at sync. Next, download the NdisWrapper package from http://prdownloads.sourceforge.net/ndiswrapper/ndiswrapper-0.9.tar.gz?download. Extract the archive as:

tar -zxvf ndiswrapper-0.9.tar.gz

This will produce a directory named ndiswrapper-0.9. Before proceeding further,install the RPM named kernel-source-2.4.22-1.2115.nptl.i386.rpm from CD3 of PCQLinux 2004 - found in the directory PCQLinux/RPMS. Change to the directory ndiswrapper-0.9 and issue the following command:

make install

Next, we need to supply the Windows driver for the WiFi card to NdisWrapper. For this either you can get the drivers from the driver CD that accompanied your notebook or download the tried and tested driver from the following URL:
ftp://www.asus.com/ pub/ASUS/nb/M2N/PROW7100_XP_v1.2.0.56_logo.zip 

Unzip the driver archive as:

unzip PROW7100_XP_v1.2.0.56_ logo.zip

This will produce a directory named PROW7100_XP_v1.2.0. 56_logo. Change to this directory and issue the following command:

ndiswrapper -i w70n51.inf

You should get an output saying 'Installing w70n51'. Note that the syntax of the above command is:

ndiswrapper -i

To confirm whether the driver has been installed, issue the following command:

ndiswrapper -l

You should be able to see an output as follows:

Installed ndis drivers:

w70n51 hardware present

Next, issue the following command to activate the driver:

insmod ndiswrapper

Now comes the task of assigning the ESSID (Extended Service Set Identifier) and IP address to the wireless LAN interface (typically wlan0). Make sure you are in the vicinity of a wireless access point and issue the following command:

iwlist wlan0 scanning

You will get an output something as below:

wlan0 Scan completed :

Cell 01 - Address: 00:0D:88:AB:20:1F

ESSID:"CyberMedia-MR"

Protocol:IEEE 802.11b

Mode:Managed

Frequency:2.437GHz

Quality:0/100 Signal level:-67 dBm Noise level:-256 dBm

Encryption key:off

Bit Rate:1Mb/s

Bit Rate:2Mb/s

Bit Rate:5.5Mb/s

Bit Rate:11Mb/s

Bit Rate:22Mb/s

Extra:bcn_int=100

Extra:atim=0

From the output, note down the ESSID (CyberMedia-MR in this case) and assign it to the wireless interface by issuing the following command:

iwconfig wlan0 essid CyberMedia-MR

Typically an access point will be running a DHCP server, in which case you can obtain an IP for your wireless interface by issuing the following command:

/sbin/dhclient wlan0

Otherwise issue the following to assign static IP address information:

netconfig -device=wlan0

Fill in the IP address, netmask, gateway and the name server information. Subsequently issue:

service network restart

You may have to again assign the ESSID by re-issuing the command stated previously. Finally, issue the following command to set up NdisWrapper to load up automatically on subsequent reboots. 

ndiswrapper -m

Besides the NdisWrapper workaround, you can find the native Linux drivers at http://ipw2100.sourceforge.net/. The requirements for these drivers state a kernel version of 2.4.26 and above, whereas the default kernel with PCQLinux 2004 is Kernel 2.4.22. In any case, you may need to recompile the kernel to install these drivers. 

Shekhar Govindarajan

IT4Enterprise