Thursday, 18 June 2009

Linux Wifi - What's going on?

When one cannot associate with a Wifi Access Point it can be helpful to find out exactly what is going on. Below is the recipe I use to see what NetworkManager is doing:

Start a bash shell as super user:

$ sudo -i

Kill the current NetworkManager:

$ killall NetworkManager

Start the script command to capture terminal output:

$ script

Start NetworkManager to run on non-daemon mode:

$ NetworkManager --no-daemon

Try to associate to your Access Point to get some debug data. Then exit the script session:

$ exit

And then look through the generate typescript file to see what NetworkManager is doing.

Alternatively, one can get some idea of what is happening using iwevent:

$ iwevent
Waiting for Wireless Events from interfaces...
07:04:25.174275 wlan0 New Access Point/Cell address:Not-Associated
07:04:57.908360 wlan0 Scan request completed
07:04:57.910007 wlan0 Set Mode:Managed
07:04:57.910038 wlan0 Set Frequency:2.412 GHz (Channel 1)

Hopefully using these methods can give you an inkling to what could be causing the problem!


  1. been following ur blog for sometime now, i tried ubuntu forum too...
    i am having this trouble ever since my university decided to go with MAC filtering with wireless access points...i am able to connect with dual booted win7 on the same system as well as with karmic on wep enabled access points..but not on MAC filtered ones...
    i am able to connect using Win 7 though.....

    it just shows connecting but never does...i tried wicd and all..

    so, everything works except connection to MAC filtered access points gets dropped...

  2. @Aditya, I suggest filing a bug against this so it's properly recorded with information about your machine, kernel version, etc.

    Use: apport-bug linux report a bug against the kernel, and please put as much detail into the bug report as possible. Thanks!