I have Debian installed on my laptop (T440s). I've installed the iwlwifi drivers but Wifi does not work. ifconfig -a only shows eth0 and lo. What should I do? Also, how do I adjust brightness?

  • Are you sure the device is enabled? ifconfig wlan0 up Feb 8, 2015 at 5:07
  • @QuaxtonHale ifconfig -a shows all devices including those that are not up.
    – myaut
    Feb 8, 2015 at 8:59
  • 3
    Have you installed the wireless card firmware? Nowadays, it is common to have cards which won't work unless you have external firmware. In Debian, this firmware is part of the non-free packages (because it's not free as in freedom). According to the debian wiki, you need to install the package firmware-iwlwifi after adding non-free to the list of package sources. Have you already tried this? (After this, you still need to restart the driver, "rmmod iwlwifi; modprobe iwlwifi".)
    – njsg
    Feb 8, 2015 at 9:15
  • Looks like there was some error or that the driver didn't pick up the wireless device. Look at the output of dmesg: if all is well you will see a line from the driver claiming the device, otherwise you'll see some error messages (quite possible complaining about a lack of firmware, as above)
    – vk5tu
    Feb 9, 2015 at 5:55
  • Lenovo often changes wifi cards IDs in order to whitelist hardware... Apr 5, 2016 at 2:20

2 Answers 2


Are you sure that you installed the driver? In Linux, drivers are treated as kernel modules and need to be loaded as such. After downloading the driver via you distribution's package manager, it must be loaded with the modprobe command.

First, download the driver:

sudo apt-get install iwlwifi-firmware

Then unload the conflicting modules

modprobe -r b44 b43 b43legacy ssb brcmsmac bcma

or, if the have been unloaded, and the iwlwifi module has been detetcted automatically:

modprobe -r iwlwifi

Next, load the iwlwifi module:

modprobe iwlwifi

That should be it!

Source: https://wiki.debian.org/iwlwifi

  • the needed driver is iwlwifi ( intel card) , the wl module isn't the right driver.
    – GAD3R
    Jun 12, 2016 at 17:26

To manage wireless interface you can use iwconfig

Check here for the list of commands, related to WiFi

  • Wireless cards should still be listed in ifconfig, as they are network interfaces.
    – njsg
    Feb 8, 2015 at 9:18
  • As far as I remember some time a go it do not show Feb 8, 2015 at 9:36
  • What card is it lspci -nnk | grep -iA2 net
    – Jeremy31
    Feb 8, 2015 at 12:37

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