Trouble shooting the presence of the ethernet link is relatively easy.
Here are a few suggestion from my limited tool box.
Following commands will show if the link is UP - if it sees a carrier
from the switch - opposite side of the cable.
old fashioned: /sbin/ifconfig will print the link status (note UP and
Tx/Rx status/errors/collisions/etc.)
> /sbin/ifconfig
eth0 Link encap:Ethernet HWaddr 50:7B:9D:04:AB:53
inet addr:192.168.1.230 Bcast:192.168.1.255
Mask:255.255.255.0
inet6 addr: fe80::527b:9dff:fe04:ab53/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:5690410 errors:0 dropped:0 overruns:0 frame:0
TX packets:1338157 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:8161292947 (7783.2 Mb) TX bytes:134265512 (128.0
Mb)
Interrupt:20 Memory:f1200000-f1220000
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:135 errors:0 dropped:0 overruns:0 frame:0
TX packets:135 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:10123 (9.8 Kb) TX bytes:10123 (9.8 Kb)
New equivalent: ip address will print more or less the same
information. Note the presence of UP/DOWN, and the fact that ifconfig
did not show the disabled wlan0 interface
> ip address
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP group default qlen 1000
link/ether 50:7b:9d:04:ab:53 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.230/24 brd 192.168.1.255 scope global dynamic eth0
valid_lft 81579sec preferred_lft 81579sec
inet6 fe80::527b:9dff:fe04:ab53/64 scope link
valid_lft forever preferred_lft forever
3: wlan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group
default qlen 1000
link/ether 94:65:9c:91:72:a6 brd ff:ff:ff:ff:ff:ff
Alternatively command "ip link" will just narrow down the print out to
link relevant info:
> ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
mode DEFAULT group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP mode DEFAULT group default qlen 1000
link/ether 50:7b:9d:04:ab:53 brd ff:ff:ff:ff:ff:ff
3: wlan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode
DEFAULT group default qlen 1000
link/ether 94:65:9c:91:72:a6 brd ff:ff:ff:ff:ff:ff
Now when I unplug the ethernet cable (Note eth0 went DOWN and NO
-CARRIER):
> ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
mode DEFAULT group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast
state DOWN mode DEFAULT group default qlen 1000
link/ether 50:7b:9d:04:ab:53 brd ff:ff:ff:ff:ff:ff
3: wlan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode
DEFAULT group default qlen 1000
link/ether 94:65:9c:91:72:a6 brd ff:ff:ff:ff:ff:ff
As about the interface naming that depends on your
kernel/distro/device.
This is example for enp3s0: Realtek RTL8111/8168 PCI Express Gigabit
Ethernet controller on kernel 3.16.7-53:
> ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
mode DEFAULT group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP mode DEFAULT group default qlen 1000
link/ether 70:85:c2:07:47:ab brd ff:ff:ff:ff:ff:ff
> /usr/sbin/hwinfo --netcard
19: PCI 300.0: 0200 Ethernet controller
[Created at pci.328]
Unique ID: UOJ9.sw6bxR4vqR7
Parent ID: hoOk.6EfNe3ljZ_F
SysFS ID: /devices/pci0000:00/0000:00:1c.2/0000:03:00.0
SysFS BusID: 0000:03:00.0
Hardware Class: network
Model: "Realtek RTL8111/8168 PCI Express Gigabit Ethernet controller"
Vendor: pci 0x10ec "Realtek Semiconductor Co., Ltd."
Device: pci 0x8168 "RTL8111/8168 PCI Express Gigabit Ethernet
controller"
SubVendor: pci 0x1849 "ASRock Incorporation"
SubDevice: pci 0x8168 "Motherboard (one of many)"
Revision: 0x11
Driver: "r8169"
Driver Modules: "r8169"
Device File: enp3s0
I/O Ports: 0xe000-0xefff (rw)
Memory Range: 0x91304000-0x91304fff (rw,non-prefetchable)
Memory Range: 0x91300000-0x91303fff (ro,non-prefetchable)
IRQ: 138 (81048274 events)
HW Address: 70:85:c2:07:47:ab
Link detected: yes
Module Alias: "pci:v000010ECd00008168sv00001849sd00008168bc02sc00i00"
Driver Info #0:
Driver Status: r8169 is active
Driver Activation Cmd: "modprobe r8169"
Config Status: cfg=no, avail=yes, need=no, active=unknown
Attached to: #15 (PCI bridge)
ifconfig can also configure some aspects of the interface, such as
bring it up/down:
sudo /sbin/ifconfig -s eth0 down
sudo /sbin/ifconfig -s eth0 up
Another useful tool is ethtool which can show or configure low level
link behavior:
> /usr/sbin/ethtool eth0
Settings for eth0:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supported pause frame use: No
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised pause frame use: No
Advertised auto-negotiation: Yes
Speed: 1000Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 1
Transceiver: internal
Auto-negotiation: on
MDI-X: on (auto)
Cannot get wake-on-lan settings: Operation not permitted
Current message level: 0x00000007 (7)
drv probe link
Link detected: yes
Example of changing link to: 100Mb/s full duples without
autonegotiation:
sudo /usr/sbin/ethtool -s eth0 speed 100 duplex full autoneg off
I hope it helps you debugging the next ethernet issue.
-Tomas
On Tue, 2017-05-16 at 21:03 -0700, Erik Lane wrote:
> I don't think you should be embarrassed about that! That would be one
> of
> the hardest things for me to troubleshoot, too. (Mainly because I
> would
> fight *everything* else before I even started to suspect the cable.
> They
> just work.)
>
> Actually it sounded to me like you caught onto it pretty quickly. I
> would
> only suspect a simple cable as an absolute last resort, especially if
> it
> was known to be working right before.
>
> On Mon, May 15, 2017 at 7:36 PM, Michael Barnes <
> barnmich...@gmail.com>
> wrote:
>
> > Red face. Turns out I had a bad Ethernet cable. It was working
> > fine, but
> > after I moved the computer while installing the new hard drive, it
> > quit
> > working. All fine now. Thanks for everyone's comments.
> >
> > Michael
> >
> >
> > On Mon, May 15, 2017 at 12:33 AM, wes <p...@the-wes.com> wrote:
> >
> > > well, I don't have any more ideas for you right now, but if you
> > > don't get
> > > it figured out by this weekend, the PLUG Clinic is this Sunday, 1
> > > -5pm.
> > >
> > > 1731 SE 10th Ave, 97214.
> > >
> > > -wes
> > >
> > > On Sun, May 14, 2017 at 11:37 PM, Michael Barnes <
> > > barnmich...@gmail.com>
> > > wrote:
> > >
> > > > It also looks like it is not using IPV4, only IPV6. Strange.
> > > >
> > > >
> > > > On Sun, May 14, 2017 at 10:40 PM, Michael Barnes <
> > barnmich...@gmail.com>
> > > > wrote:
> > > >
> > > > > More info seems to lead to more questions. Apparently this
> > > > > has
> > > something
> > > > > to do with systemd. I guess this is a new (to me) thing and
> > > > > it
> > changes
> > > > the
> > > > > way stuff is named. So, what used to be eth0 is now enp3s0.
> > > > > But,
> > trying
> > > > the
> > > > > usual network commands with that don't work either.
> > > > >
> > > > > Michael
> > > > >
> > > > >
> > > > > On Sun, May 14, 2017 at 10:04 PM, wes <p...@the-wes.com>
> > > > > wrote:
> > > > >
> > > > > > my first step is usually to find the model number in the
> > > > > > lspci
> > output,
> > > > and
> > > > > > the google that number along with ubuntu 16.04 and see if
> > > > > > anyone's
> > > > posted
> > > > > > a
> > > > > > guide.
> > > > > >
> > > > > > -wes
> > > > > >
> > > > > > On Sun, May 14, 2017 at 9:28 PM, Michael Barnes <
> > > barnmich...@gmail.com>
> > > > > > wrote:
> > > > > >
> > > > > > > Installed 16.04 LTS via flash drive to new hard drive.
> > > > > > > Only took a
> > > few
> > > > > > > minutes! Previous DVD installs took much, much longer.
> > > > > > > Anyhow, so
> > > far,
> > > > > > no
> > > > > > > network. Sadly, my Linux memory has become very foggy, so
> > > > > > > please
> > > > forgive
> > > > > > > the noobie type questions. I don't seem to be finding
> > > > > > > eth0. Using
> > > > > > lspci, I
> > > > > > > find the info for the onboard Broadcom Ethernet adapter,
> > > > > > > but under
> > > > > > > 'Capabilities' it says ". Running ifconfig
> > > > > > > does not
> > > > show
> > > > > > > eth0, but it does show enp3s0. If I try "sudo ifup eth0"
> > > > > > > I get
> > > > "Unknown
> > > > > > > interface eth0."
> > > > > > >
> > > > > > > I'm kind of surprised at the minimum of questions and the
> > > > > > > speed of
> > > the
> > > > > > > install. I wonder what else will not be working?
> > > > > > >
> > > > > > > Thanks for your comments,
> > > > > > >
> > > > > > > Michael
> > > > > > >
> > > > > > >
> > > > > > > On Sun, May 14, 2017 at 8:42 PM, Michael Barnes <
> > > > barnmich...@gmail.com>
> > > > > > > wrote:
> > > > > > >
> > > > > > > > I figured the quickest and easiest was probably to
> > > > > > > > start all
> > over.
> > > > It
> > > > > > > > looks like all my files, pictures, documents, etc. are
> > > > > > > > still
> > > intact.
> > > > > > I'll
> > > > > > > > just stick in a new hard drive, install 16.04 LTS from
> > > > > > > > scratch,
> > > then
> > > > > > copy
> > > > > > > > what I need from the old drive to the new one. Thanks
> > > > > > > > for
> > > everyone's
> > > > > > > > comments.
> > > > > > > >
> > > > > > > > Michael
> > > > > > > >
> > > > > > > >
> > > > > > > > On Sat, May 13, 2017 at 12:51 AM, Nat Taylor <
> > > > > > > > biob...@gmail.com
> > >
> > > > > > wrote:
> > > > > > > >
> > > > > > > > > instead of comparing xorg files, I'd want to get it
> > > > > > > > > to try to
> > > > > > > > > automagically
> > > > > > > > > configure stuff fresh, maybe with a *sudo dpkg
> > > > > > > > > -reconfigure
> > xorg*
> > > > and
> > > > > > a
> > > > > > > > > *sudo
> > > > > > > > > apt update && sudo apt upgrade && sudo apt dist
> > > > > > > > > -upgrade*
> > > > > > > > > Maybe try dpkg-reconfiguring your window manager
> > > > > > > > > (unity?)
> > > > > > > > > -- did it disable the universe or multiverse for the
> > > > > > > > > upgrade
> > and
> > > do
> > > > > > you
> > > > > > > > > need to reenable it?
> > > > > > > > > Check your /etc/apt/sources.list and
> > > > > > > > > /etc/apt/sources.list.d/
> > > > > > > > >
> > > > > > > > > Did you do the upgrade to 16.04 by manually editing
> > > > > > > > > the
> > sources,
> > > or
> > > > > > did
> > > > > > > > > you
> > > > > > > > > use the tool in the Software Center, or did you
> > > do-release-upgrade
> > > > > > from
> > > > > > > > > the
> > > > > > > > > command line?
> > > > > > > > >
> > > > > > > > > On Fri, May 12, 2017 at 3:20 PM, Michael Barnes <
> > > > > > barnmich...@gmail.com>
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Yeah, I got to thinking after I started I shouldn't
> > > > > > > > > > have done
> > > > that.
> > > > > > > > > > Everything has been packed away for almost a year.
> > > > > > > > > > It seems
> > > I've
> > > > > > > > > forgotten
> > > > > > > > > > more than I remember. A new hard drive is probably
> > > > > > > > > > in order.
> > > I'll
> > > > > > have
> > > > > > > > > to
> > > > > > > > > > compare Xorg files and look at drivers loaded
> > > > > > > > > > between the two
> > > > > > > versions.
> > > > > > > > > > Just have to remember how to do all that.
> > > > > > > > > >
> > > > > > > > > > Michael
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > On Fri, May 12, 2017 at 1:44 PM, Edward Koenig <
> > > > > > kingbeow...@gmail.com
> > > > > > > >
> > > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Michael
> > > > > > > > > > > If the new version boots and you can ssh to log
> > > > > > > > > > > in, then
> > most
> > > > > > likely
> > > > > > > > > > > either X.org or a GPU driver did not update fully
> > > > > > > > > > > or
> > > correctly.
> > > > > > This
> > > > > > > > > is
> > > > > > > > > > > very typical for proprietary nvidia drivers, or
> > > > > > > > > > > any
> > > proprietary
> > > > > > > > > hardware
> > > > > > > > > > > drivers that install a kernel module. You might
> > > > > > > > > > > try using
> > the
> > > > > > > command
> > > > > > > > > > line
> > > > > > > > > > > tools to reinstall the GPU and X bits. I'm not
> > > > > > > > > > > sure it
> > > Ubuntu
> > > > > > > > > switched
> > > > > > > > > > to
> > > > > > > > > > > wayland with this release so perhaps check on
> > > > > > > > > > > that.
> > Remember
> > > > to
> > > > > > > read
> > > > > > > > > the
> > > > > > > > > > > release notes etc before clicking "upgrade"
> > > > > > > > > > >
> > > > > > > > > > > Nuking from orbit, as Dick suggests after backup,
> > > > > > > > > > > will
> > > > certainly
> > > > > > > work.
> > > > > > > > > > > Personally run a Linux distribution to avoid such
> > > "windowesque"
> > > > > > > fixes.
> > > > > > > > > > >
> > > > > > > > > > > Ed
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > > On May 12, 2017, at 11:36 AM, Dick Steffens <
> > > > > > > d...@dicksteffens.com>
> > > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > > On 05/12/2017 11:24 AM, Michael Barnes wrote:
> > > > > > > > > > > > > I rebooted again and at the grub screen chose
> > > > > > > > > > > > > 14.04LTS.
> > > > > > > Everything
> > > > > > > > > > came
> > > > > > > > > > > up
> > > > > > > > > > > > > normally. After login, I get a pop-up window
> > > > > > > > > > > > > that says
> > > 14.04
> > > > > > is
> > > > > > > out
> > > > > > > > > > > dated
> > > > > > > > > > > > > and no longer supported. Anyhow, display and
> > > > > > > > > > > > > everything
> > > > works,
> > > > > > > so I
> > > > > > > > > > > know at
> > > > > > > > > > > > > least the hardware is okay. Shutdown and
> > > > > > > > > > > > > restart, let
> > grub
> > > > > > screen
> > > > > > > > > > choose
> > > > > > > > > > > > > default and back to blank screens. I can ssh
> > > > > > > > > > > > > in and
> > > shutdown
> > > > > > from
> > > > > > > > > > remote
> > > > > > > > > > > > > session. Screens give Ubuntu shutdown splash
> > > > > > > > > > > > > just before
> > > > power
> > > > > > > off.
> > > > > > > > > > > >
> > > > > > > > > > > > Having been on this list a fairly long time,
> > > > > > > > > > > > I've
> > followed
> > > > the
> > > > > > > > > advice
> > > > > > > > > > of
> > > > > > > > > > > > others who say one should not use the "upgrade"
> > > > > > > > > > > > path to
> > > move
> > > > > > from
> > > > > > > > > one
> > > > > > > > > > > > Ubuntu release to another, but should start
> > > > > > > > > > > > with a fresh
> > > > > > install.
> > > > > > > I
> > > > > > > > > > have
> > > > > > > > > > > > gone from Ubuntu 10 to 12 to 14, and am slowly
> > > > > > > > > > > > moving to
> > > 16.
> > > > > > Each
> > > > > > > > > time
> > > > > > > > > > I
> > > > > > > > > > > > had the luxury of being able to at least put in
> > > > > > > > > > > > a fresh
> > > hard
> > > > > > drive
> > > > > > > > > for
> > > > > > > > > > > > the new version, and then mount the old hard
> > > > > > > > > > > > drive to be
> > > able
> > > > > > to
> > > > > > > > > copy
> > > > > > > > > > > > files as needed. I don't think any of the
> > > > > > > > > > > > episodes has
> > been
> > > > > > > > > painless,
> > > > > > > > > > > > since it seems there's always something big
> > > > > > > > > > > > that changes
> > so
> > > > > > that
> > > > > > > it
> > > > > > > > > > > > doesn't work the way it did in the previous
> > > > > > > > > > > > version, but
> > I
> > > > have
> > > > > > > > > always
> > > > > > > > > > > > been able to get past it, often with the help
> > > > > > > > > > > > of folks on
> > > > this
> > > > > > > list.
> > > > > > > > > > > >
> > > > > > > > > > > > So, in your case, I'd recommend using Grub to
> > > > > > > > > > > > boot to
> > your
> > > > > > > previous
> > > > > > > > > > > > version, find a way to back up all your
> > > > > > > > > > > > important files,
> > > and
> > > > > > > > > install 16
> > > > > > > > > > > > from scratch. Better would be to have two
> > > > > > > > > > > > machines, but
> > not
> > > > > > > everyone
> > > > > > > > > > has
> > > > > > > > > > > > that luxury. I'm happy that I do have that
> > > > > > > > > > > > option this
> > > time,
> > > > > > > because
> > > > > > > > > > > > there are a handful of things I have yet to be
> > > > > > > > > > > > able to
> > > figure
> > > > > > out
> > > > > > > > > how
> > > > > > > > > > to
> > > > > > > > > > > > do in 16 that I need on at least a weekly
> > > > > > > > > > > > basis, if not a
> > > > daily
> > > > > > > one.
> > > > > > > > > > > >
> > > > > > > > > > > > --
> > > > > > > > > > > > Regards,
> > > > > > > > > > > >
> > > > > > > > > > > > Dick Steffens
> > > > > > > > > > > >
> > > > > > > > > > > > _______________________________________________
> > > > > > > > > > > > PLUG mailing list
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> > > > > > > > > > > _______________________________________________
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> > > > > > > > >
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> > > > > > > >
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