cjolley's questions

I'm running 22.04.1 on a Lenovo X220 laptop. I was having some trouble with a faulty fan, and just replaced it with a new one. When I put everything back together and booted it up, my fan issues were solved, but wi-fi seems not to work anymore.

I'm concerned that either:

1. I somehow damaged the wi-fi card when taking the computer apart, or
2. My OS has mysteriously forgotten about the card and somehow needs to be reminded.

Any ideas on how to tell the difference between these two things? Here's what I know so far:

lspci -k shows two entries that seem relevant:

00:19.0 Ethernet controller: Intel Corporation 82579LM Gigabit Network Connection (Lewisville) (rev 04)
    Subsystem: Lenovo ThinkPad T520
    Kernel driver in use: e1000e
    Kernel modules: e1000e

for my ethernet (which works just fine), and

03:00.0 Network controller: Intel Corporation Centrino Advanced-N 6205 [Taylor Peak] (rev 34)
    Subsystem: Intel Corporation Centrino Advanced-N 6205 (802.11a/b/g/n)
    Kernel driver in use: iwlwifi
    Kernel modules: iwlwifi

for the wi-fi. I get something similar from lshw:

           *-network
                description: Network controller
                product: Centrino Advanced-N 6205 [Taylor Peak]
                vendor: Intel Corporation
                physical id: 0
                bus info: pci@0000:03:00.0
                version: 34
                width: 64 bits
                clock: 33MHz
                capabilities: pm msi pciexpress bus_master cap_list
                configuration: driver=iwlwifi latency=0
                resources: irq:30 memory:d2400000-d2401fff

It looks like my firmware is OK:

$ sudo dmesg | grep iwlwifi
[   15.853806] iwlwifi 0000:03:00.0: can't disable ASPM; OS doesn't have ASPM control
[   16.302507] iwlwifi 0000:03:00.0: loaded firmware version 18.168.6.1 6000g2a-6.ucode op_mode iwldvm

I don't know if the ASPM thing is a big deal; I ran sudo fwts aspm and it gave some warnings about L0s not enabled but no obvious failures.

However, it seems like nmcli doesn't know about the wi-fi card. If I unplug the ethernet cable (since it's not relevant here), I get:

np0s25: unavailable
        "Intel 82579LM"
        ethernet (e1000e), F0:DE:F1:62:D6:31, hw, mtu 1500

lo: unmanaged
        "lo"
        loopback (unknown), 00:00:00:00:00:00, sw, mtu 65536

Any ideas about what might be wrong here?

UPDATE: I ran the wireless-info script from this post and pasted the results at: https://pastebin.com/dEbb2i4a

I just got a Dell XPS 13 with Ubuntu 16.04 pre-installed, and I'm still working out all of the new-computer kinks. I'm using a Thunderbolt docking station (StarTech) to connect my peripherals. Keyboard, mouse, etc. are all fine, but the monitor is tripping me up.

I'm using a Samsung monitor (S27C230B) that only has RGB and DVI inputs, and the StarTech dock only has DisplayPort and USB-C outputs. I've got a DisplayPort-to-DVI cable, and was able to connect the monitor to my old Lenovo laptop (which has a DisplayPort plug on it, but no Thunderbolt) without any trouble. When I plug it into the dock, though, I see nothing. Neither the computer nor the monitor seems to acknowledge that there is a connection.

I tried installing the DisplayLink Ubuntu drivers (http://www.displaylink.com/downloads/ubuntu), but I can't really tell whether anything happened as a result of this. Their support site (https://support.displaylink.com/knowledgebase/articles/684649) shows the ouptput one ought to see in the terminal, and I'm missing the last two lines ("Starting DLM upstart job" and "displaylink start/running, process 3397").

If it helps, my lsusb output is:

Bus 006 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 005 Device 002: ID 058f:9410 Alcor Micro Corp. Keyboard
Bus 005 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 002: ID 04f2:0939 Chicony Electronics Co., Ltd 
Bus 003 Device 003: ID 0d8c:0022 C-Media Electronics, Inc. 
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 0489:e0a2 Foxconn / Hon Hai 
Bus 001 Device 002: ID 0bda:58f4 Realtek Semiconductor Corp. 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Any ideas about how I can debug this? Would I be better off with a USB-C-to-DVI cable instead?

Thanks!

I've got a new laptop running Ubuntu 16.04 that worked like a charm for a couple of weeks but has now lost its appetite for connecting to the internet via Wi-fi. I know it's not a problem with my router or ISP, because I'm writing this post using my old Windows laptop on the exact same home network by Ubuntu laptop won't connect to.

I'm connecting to my router successfully, and running nmcli dev shows that I'm connected to my wifi device (wlp2s0) and to the wireless network.

Last night I was able to open some pages (Google, Facebook, YouTube), but not others (ubuntu.com, riken.jp). At the time I suspected it was something where IPv6 was working but IPv4 wasn't. Now, however, nothing works. Chromium, ping, wget, dig -- nothing. /etc/resolv.conf/ contains nothing at all (beyond the comment lines telling me not to edit it), and the table returned by route is empty.

UPDATE 1: I used ipconfig /all on my Windows machine to figure out which DNS servers it was using (75.75.75.75, 75.75.76.76., 2001:558:feed::1, 2001:558:feed::2), then used Network Connections to add these as DNS Servers for my home network. cat /etc/resolv.conf now gives me nameserver 127.0.1.1; I'm not entirely sure what this means, but I think it's some kind of alias, right? nmcli dev show | grep DNS shows me as using the two IPv6 DNS servers (2001:558:feed::1 and 2001:558:feed::2).

I can get wget to work with URLs that resolve to an IPv6 address, like so:

craig@craig-XPS-13-9370:~$ wget www.google.com
--2018-04-14 13:06:17--  http://www.google.com/
Resolving www.google.com (www.google.com)... 2607:f8b0:4004:808::2004, 
172.217.13.68
Connecting to www.google.com 
(www.google.com)|2607:f8b0:4004:808::2004|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [text/html]
Saving to: ‘index.html.5’

index.html.5            [ <=>                ]  10.41K  --.-KB/s    in 0.003s  

2018-04-14 13:06:17 (3.36 MB/s) - ‘index.html.5’ saved [10659]

I can't get a wget request to work with URLs that resolve to an IPv4 address:

craig@craig-XPS-13-9370:~$ wget www.ubuntu.com
--2018-04-14 13:06:28--  http://www.ubuntu.com/
Resolving www.ubuntu.com (www.ubuntu.com)... 91.189.89.118
Connecting to www.ubuntu.com (www.ubuntu.com)|91.189.89.118|:80... failed: 
Network is unreachable.

Adding the -4 flag to wget to force IPv4 usage gets a similar result:

craig@craig-XPS-13-9370:~$ wget -4 www.google.com
--2018-04-14 13:06:41--  http://www.google.com/
Resolving www.google.com (www.google.com)... 172.217.13.68
Connecting to www.google.com (www.google.com)|172.217.13.68|:80... failed: 
Network is unreachable.

Similarly, ping www.google.com doesn't work, but ping6 www.google.com does. So it's pretty clear that something is wrong with IPv4, but I'm not sure what...

UPDATE 2: I thought my problem looked pretty similar to this question, but the solution suggested there (disabling IPv4 via Network Connections) doesn't seem to have affected anything. It did give me some ideas for what it's useful to share with others, though:

Output from cat /etc/network/interfaces:

craig@craig-XPS-13-9370:~$ cat /etc/network/interfaces
# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback

Output from ifconfig:

craig@craig-XPS-13-9370:~$ ifconfig
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:13526 errors:0 dropped:0 overruns:0 frame:0
          TX packets:13526 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1 
          RX bytes:1031920 (1.0 MB)  TX bytes:1031920 (1.0 MB)

wlp2s0    Link encap:Ethernet  HWaddr 9c:b6:d0:8b:4b:c5  
          inet6 addr: fe80::1f3b:5545:508:919a/64 Scope:Link
          inet6 addr: 2601:140:8600:e0:d64b:9272:665f:3734/64 Scope:Global
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:19665 errors:0 dropped:0 overruns:0 frame:0
          TX packets:10262 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:14731745 (14.7 MB)  TX bytes:1722860 (1.7 MB)

Output from iwconfig:

craig@craig-XPS-13-9370:~$ iwconfig
lo        no wireless extensions.

wlp2s0    IEEE 802.11abgn  ESSID:"MOTOROLA-ABD39"  
          Mode:Managed  Frequency:2.447 GHz  Access Point: 34:1F:E4:E4:35:D0   
          Bit Rate=1 Mb/s   Tx-Power=20 dBm   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:on
          Link Quality=55/70  Signal level=-55 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:39   Missed beacon:0

Output from cat /etc/resolv.conf:

craig@craig-XPS-13-9370:~$ cat /etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 127.0.1.1

Output from route -n:

craig@craig-XPS-13-9370:~$ route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface

Output from route -6 -n:

craig@craig-XPS-13-9370:~$ route -6 -n
Kernel IPv6 routing table
Destination                    Next Hop                   Flag Met Ref Use If
2601:140:8600:e0::/64          ::                         U    600 0     0 wlp2s0
2601:140:8600:e0::/60          fe80::361f:e4ff:fee4:35cf  UG   600 0     0 wlp2s0
fe80::/64                      ::                         U    256 0     0 wlp2s0
::/0                           fe80::361f:e4ff:fee4:35cf  UG   600 2     4 wlp2s0
::/0                           ::                         !n   -1  1  1495 lo
::1/128                        ::                         Un   0   7    46 lo
2601:140:8600:e0:d64b:9272:665f:3734/128 ::                         Un   0   2   150 lo
fe80::1f3b:5545:508:919a/128   ::                         Un   0   2     4 lo
ff00::/8                       ::                         U    256 7    99 wlp2s0
::/0                           ::                         !n   -1  1  1495 lo

Output from ip neigh:

craig@craig-XPS-13-9370:~$ ip neigh
fe80::361f:e4ff:fee4:35cf dev wlp2s0 lladdr 34:1f:e4:e4:35:cf router REACHABLE