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I recently installed Ubuntu 12.04 LTS. I'm facing the following 2 problems that I don't understand how to solve it:

  1. Wireless connection was running normally when I installed the Ubuntu without the need of any additional driver, however on the next day it just stopped to detect any available wireless connection.

  2. Due to 1st problem, I connected my PC to my Internet huddle with cable. It works pretty smoothly, but on the next day it stopped working working again (I did installed 2 new language package on that day - Korean and Chinese simplify). And what confused me even more is that suddenly my wireless connection started to work again.

It is like the OS alternatively disable & enable all my network adapter.

I'm new to Ubuntu or Linux in general, I don't know what configuration I have to do. What are the information I need to provide here in order to understand & solve my problem?

Connectors details:

Wireless : D-Link Wireless N 150 USB adapter

huddle : Yes Huddle 4G mobile hotspot (from

Other details: sudo rfkill list

0: phy0: Wireless LAN
    Soft blocked: no
    Hard blocked: no
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Odd... you should check out the output of "sudo dmesg" when it happens again, it may contain some messages from the kernel about what exactly is going on. Also an output of "ifconfig -a" and "iwconfig -a" would be good.

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I tried to run "sudo dmesg" as you told me, I found message:

when I plugged in the Wireless connector if not working it will only show:

> [  611.981365] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready [ 
> 611.983024] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready

and when u connected with huddle if not working it will show:

[  321.102476] cfg80211: Updating information on frequency 2472 MHz for a 20 MHz width channel with regulatory rule:
[  321.102477] cfg80211: 2402000 KHz - 2482000 KHz @ 20000 KHz), (N/A mBi, 2000 mBm)
[  321.102479] cfg80211: Disabling freq 2484 MHz
[  321.102481] cfg80211: Regulatory domain changed to country: KR
[  321.102482] cfg80211:   (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
[  321.102484] cfg80211:   (2402000 KHz - 2482000 KHz @ 20000 KHz), (N/A, 2000 mBm)
[  321.102486] cfg80211:   (5170000 KHz - 5250000 KHz @ 20000 KHz), (300 mBi, 2000 mBm)
[  321.102488] cfg80211:   (5250000 KHz - 5330000 KHz @ 20000 KHz), (300 mBi, 2000 mBm)
[  321.102490] cfg80211:   (5490000 KHz - 5630000 KHz @ 20000 KHz), (300 mBi, 3000 mBm)
[  321.102492] cfg80211:   (5735000 KHz - 5815000 KHz @ 20000 KHz), (300 mBi, 3000 mBm)
[  322.284859] type=1400 audit(1369452341.537:28): apparmor="DENIED" operation="capable" parent=1 profile="/usr/sbin/cupsd" pid=975 comm="cupsd" pid=975 comm="cupsd" capability=36  capname="block_suspend"

does it mean my Ubuntu does not recognize or unable to detect those devices?

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