Well a lot of my time was wasted in handling wifi in Backtrack 4 on my laptop ..
well there were reasons and hence I just want to put some points which would certainly ease the process for 1st timers if things get confusing.

1. Enter the command in console before doing anything else

Code:

 /etc/init.d/networking start

2. Watch the interfaces getting load .. eth0 , l0 , etc etc .. If it gives "wlan0 found" (or similar interface),work is going to be easy then.

3. Next step is to know the wireless card you have in your laptop.

Code:

lspci | grep Network

if broadcom card .. maybe then tough road ahead

4. Now

Code:

/etc/init.d/wicd start

Code:

start-network

Code:

 sudo wicd start

Try all of the above or all three.
Start Wicd manger from KDE

5. check by

Code:

 iwconfig

whether wlan0 is up.Also try

Code:

iwconfig wlan0 up

to bring it in iwconfig.

6. Still no sign of wlan0.Try jockey-gtk b43 driver.Scroll down.

7. Still no sign of wlan0 ? have a fair peek at http://linuxwireless.org/en/users/Drivers/
and http://www.backtrack-linux.org/wiki/...reless_Drivers and find about supported driver installations and mode of operations.Just keep reading

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Dealing Broadcom ( Credits : stormeye)

Now this is 1 card which will give you nightmares with all Linux installations.

Anyways 1st try jockey-gt
Log into BackTrack as root and run these commands:

Code:

/etc/init.d/networking start apt-get install jockey-gtk jockey-gtk

Then follow the instructions on the program that starts.Still problems ? try manually..

Downloading drivers manually >>
Go to: Broadcom.com - 802.11 Linux STA driver
And download the tarball for your system (32 or 64).

Run the following in the terminal:

Code:

/etc/init.d/networking start tar xzf nameoffile.tar.gz cd thefolderyouget make clean make

Now let's check if you have any conflicting drivers (you shouldn't, they doesn't come with BT.)

Code:

lsmod  | grep "b43\|ssb\|wl" If any of these are installed, remove them: rmmod b43 rmmod ssb rmmod wl

Then let's insmod the driver:

Code:

modprobe lib80211 insmod wl.ko

Note: You maybe have to start network through the KDE "start menu" before you get the WICD manager up, then you should see networks.

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some more pointers >>

Code:

lspci -vnn | grep 14e4

gives you Broadcom BCM4312 .. then well update your kernel to 2.6.33.Then also I think packet injection for wifi attacks won't work.It works partially only.

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Let us see ..maybe Backtrack 5 has more to offer in handling wifi experience.It is coming out on May 10th, 2011 !