Wireless DHCP configuration fails on open network

Question

I upgraded to Kubuntu Trusty last summer, and now that I'm back in school, I've noticed that my laptop has been failing to connect to the school's wireless (which is a completely open network). Every time I try to connect, it says Connecting for a while, and then it fails with the error message:

IP configuration was unavailable

Or, if I play with the wireless setup (changing the driver, using direct commandline methods to connect to the network), then the error message changes:

Authorization supplicant timed out

which is weird, because there's no need to authenticate anything (it's an open network).

It's interesting, because I know that my current setup can connect to a wireless network, as it works perfectly fine at home (which, unlike the school network, is locked down), and it uses DHCP there as well.

I've tried running sudo dhclient wlan0, but nothing happens.

My wireless card is a Broadcom BCM4313, and I'm using the wl driver.

Any suggestions?

Please run the script that is in the accepted answer in the link below so we may see the information needed to help diagnose the issue. http://askubuntu.com/questions/425155/my-wireless-wifi-connection-does-not-work-what-can-i-do — Wild Man, Aug 26 '14 at 12:50
http://pastebin.ubuntu.com/8150392/ I should note that, despite the last line from dmesg, turning power management off does not change anything. Also, I noticed that the brcmsmac driver was installed (which was what I was using before), but switching to it did not change anything. — hal7df, Aug 26 '14 at 14:37

score 0 · Accepted Answer · answered Aug 26 '14 at 15:35

For your device in 14.04 brcmsmac is the best driver in most cases and it is best if power management is off.

Please do:

sudo apt-get purge bcmwl-kernel-source

Then reboot and make sure only the brcmsmac and bcma driver is loaded they are both currently blacklisted so you may have to unblacklist them by doing:

gksudo gedit /etc/modprobe.d/blacklist.conf

Then remove brcmsmac and bcma save the file then close gedit and reboot.

You may have to install gksudo.

gksudo gedit /etc/pm/power.d/wireless

(this will create or edit a configuration file that will override the default power management behavior) and enter the following:

#!/bin/sh

/sbin/iwconfig wlan0 power off

above exit0, then save gedit, close and reboot.

Change the channel to 6 if you can 4 people on that network are using 1 and 11 so that can cause issues.

After you make these changes if you still can not connect then post a new file from the script.

It worked without turning power management off (I don't know why it didn't work before). If there's a problem, I'll turn off power management, but for now, I'll leave it on. Also, purging bcmwl-kernel-source removed the blacklist file in question. — hal7df, Aug 26 '14 at 15:56
I thought the purge command would but for some reason sometimes it does not. — Wild Man, Aug 26 '14 at 16:12

Wireless DHCP configuration fails on open network

1 Answers1