I am new to Ubuntu 16.04. on my Dell laptop

I was using windows10 and i did a dual boot in my pc.

It looks everything is good but i am not able to detect wifi connection.

when i did iwconfig

enp7s0    no wireless extensions.

lo        no wireless extensions.

After using this lspci -knn | grep Net -A2

06:00.0 Network controller [0280]: Broadcom Corporation BCM43142 802.11b/g/n [14e4:4365] (rev 01)
    Subsystem: Dell Wireless 1704 802.11n + BT 4.0 [1028:0016]
    Kernel modules: bcma, wl

this above error was showing.

But my wifi is working fine in my window10.

  • Please edit your question and add output of lspci -knn | grep Net -A2 terminal command.
    – Pilot6
    Aug 1, 2016 at 10:06
  • @Pilot6 please check my updated question
    – Mohan Gopi
    Aug 1, 2016 at 10:30
  • 1
    Disable Secure Boot in BIOS.
    – Pilot6
    Aug 1, 2016 at 10:31
  • it asked the password and after restarting the system i gave change boot state then i entered the password but it says it is not correct password
    – Mohan Gopi
    Aug 1, 2016 at 10:43
  • It is much easier to disable secure boot in bios than using mokutil. If you want to use mokutil, you need to carefuuly read the directions. In some cases it does not ask for a password, but to enter some characters of a password, like 1st, 3rd, etc. But I suggest to get into BIOS and simply disable it there.
    – Pilot6
    Aug 1, 2016 at 10:45

1 Answer 1


You need to install bcmwl-kernel-source.

For installing this go to your terminal and give sudo apt-get install bcmwl-kernel-source command. Do a reboot after completing the installation and give this sudo modprobe wl command on the terminal.

Hope that's gonna fix your problem.

  • after using this sudo modprobe wl i am getting this modprobe: ERROR: could not insert 'wl': Required key not available
    – Mohan Gopi
    Aug 1, 2016 at 10:30
  • bcmwl-kernel-source is already installed. It is shown by wl kernel module.
    – Pilot6
    Aug 1, 2016 at 10:32
  • Can you please try this sudo ifconfig wlp4s0 up service network-manager restart. Let me know what happens.
    – CodeMascot
    Aug 1, 2016 at 10:33
  • 1
    There is no need in that. The problem is with Secure Boot.
    – Pilot6
    Aug 1, 2016 at 10:34
  • Do you mind telling what was the problem with Secure Boot?
    – HelmBurger
    Sep 3, 2019 at 14:11

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