I just installed Ubuntu Karmic Koala 9.10 on my aging and old Dell Inspiron E1405 laptop, but my WiFi was broken, and not working with the default install. So I researched a bit on the internet, and fixed my problem within 15 minutes. I found many forums advising noobs (like me) to do some stuff using ndiswrapper. However, I got away simply with installing a few packages.

Before following what is said, you should check your WLAN manufacturer. You can do this by executing “lspci | grep Network”. Mine is Broadcom Network controller: Broadcom Corporation BCM4311 802.11b/g WLAN (rev 01).

Just run the following two commands, and your system should work fine -
$ sudo apt-get install linux-backports-modules-karmic-generic
$ sudo apt-get install bw43-cutter

Package linux-backports-modules-karmic-generic enables Fn + F2 key to enable WiFi hardware (do that! The led should be on). bw43-cutter gets the proprietary Broadcom drivers and cuts out whatever is relevant to Ubuntu, places in the right directories, updates config etc. Sometimes you would need to update aptitude repository info by doing “apt-get update”.

Now do -
$ sudo ifconfig wlan0 up

These tips should also work with older versions of Ubuntu like Jaunty and Hardy, just update the package name “linux-backports-modules-XXXXX-generic” accordingly.

That’s it ! Enjoy !

References:

• http://ubuntuforums.org/showthread.php?t=947644
• https://help.ubuntu.com/community/WifiDocs/Driver/bcm43xx

I would recommend non-geek beginners to read a simple guides to getting started on Ubuntu -