No WiFi / Intel Centrino Advanced-N 6205 [Missing Drivers/ Firmware] Ubuntu 16.04.2

Question

First an foremost: I am a absolute Linux beginner, so have mercy if my problem seems easy to you. My Brother gave me his old T420, so I decided to learn Linux and install Ubuntu on it. Unfortunately I can't establish a WiFi connection (my brother assured me it worked when he used it) so I'm pretty positive it's not a Hardware problem. In the terminal he finds the Network adapter when I type

lspci
03:00.0 Network controller: Intel Corporation Centrino Advanced-N 6205 [Taylor Peak] (rev 34)

I'm pretty sure I'm missing the required drivers, but I cant find a way to download them, as I'm used to just download them directly from the manufacturers site under windows. Sorry if I seem so super stupid, but this is all pretty new for me. Here are the commands I found in other threats:

ifconfig

enp0s25   Link encap:Ethernet  HWaddr 00:21:cc:5e:b2:30  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:3069 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2616 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:2298050 (2.2 MB)  TX bytes:316024 (316.0 KB)
          Interrupt:20 Memory:f2500000-f2520000 

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:3819 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3819 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1 
          RX bytes:257315 (257.3 KB)  TX bytes:257315 (257.3 KB)

sudo rfkill list

0: tpacpi_bluetooth_sw: Bluetooth
    Soft blocked: yes
    Hard blocked: yes
1: phy0: Wireless LAN
    Soft blocked: no
    Hard blocked: yes

sudo lshw -class network

*-network               
       description: Ethernet interface
       product: 82579LM Gigabit Network Connection
       vendor: Intel Corporation
       physical id: 19
       bus info: pci@0000:00:19.0
       logical name: enp0s25
       version: 04
       serial: 00:21:cc:5e:b2:30
       size: 1Gbit/s
       capacity: 1Gbit/s
       width: 32 bits
       clock: 33MHz
       capabilities: pm msi bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=3.2.6-k duplex=full firmware=0.13-3 ip=192.168.178.29 latency=0 link=yes multicast=yes port=twisted pair speed=1Gbit/s
       resources: irq:24 memory:f2500000-f251ffff memory:f252b000-f252bfff ioport:5080(size=32)
  *-network DISABLED
       description: Wireless interface
       product: Centrino Advanced-N 6205 [Taylor Peak]
       vendor: Intel Corporation
       physical id: 0
       bus info: pci@0000:03:00.0
       logical name: wlp3s0
       version: 34
       serial: a0:88:b4:4b:94:3c
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=iwlwifi driverversion=4.8.0-36-generic firmware=18.168.6.1 latency=0 link=no multicast=yes wireless=IEEE 802.11
       resources: irq:29 memory:f2400000-f2401fff

dmesg | grep iwl

[   10.492168] iwlwifi 0000:03:00.0: can't disable ASPM; OS doesn't have ASPM control
[   10.702888] iwlwifi 0000:03:00.0: loaded firmware version 18.168.6.1 op_mode iwldvm
[   10.914050] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_DEBUG disabled
[   10.914052] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_DEBUGFS enabled
[   10.914052] iwlwifi 0000:03:00.0: CONFIG_IWLWIFI_DEVICE_TRACING enabled
[   10.914054] iwlwifi 0000:03:00.0: Detected Intel(R) Centrino(R) Advanced-N 6205 AGN, REV=0xB0
[   10.915537] iwlwifi 0000:03:00.0: L1 Enabled - LTR Disabled
[   10.915748] iwlwifi 0000:03:00.0: RF_KILL bit toggled to disable radio.
[   10.950926] ieee80211 phy0: Selected rate control algorithm 'iwl-agn-rs'
[   12.287868] iwlwifi 0000:03:00.0 wlp3s0: renamed from wlan0

sudo iwlist scan

enp0s25   Interface doesn't support scanning.

lo        Interface doesn't support scanning.

wlp3s0    Interface doesn't support scanning : Network is down

Sorry for spamming, I just wanted to make sure you got everything you might need. Also, as another piece of information, when I start the PC, right before he boots Ubuntu, the screen shows the Intel Boot Agent. He shows a new line, saying: DHCP... and waits there for 30 seconds, after that he states that something is missing (too short for me to read) and goes on. Everywhere I look it says, that most of the drivers are included in Ubuntu and if someone had this problem, he was running on an old release. Im using 16.04.2, but I also tried 17.04 - without a change. Even Intel states, that this device is supported by Ubuntu.

Ethernet is working fine, btw.

If anyone is willing to help me - thanks. I'm sitting here for 6 hours and cant figure it out. Thanks in advance.

Solution

Now I'm feeling even dumber then 5 mins ago when posting this. There was indeed a tiny little switch on the side of the Notebook, disabling all wireless traffic. If I knew about this, the last hours wouldnt have been such a struggle. Thanks Pilot6 for the hint. I'm feeling to ashamed leaving this post, but I will, maybe it will help others... Case closed.

Comments

[Pilot6]

Everything is OK with drivers. The problem is with rfkill block. Check hardware switch or bios settings.

[willbert]

Wow, that was quick. Thanks, i will check it out.

[Dennis]

Yes I feel like an idiot, it even shut down a known good usb adapter. However it is a new-to-me computer and who would have thought it. Thanks for the post, who knows how much time it saved me, always looking for the tricky solution.