Ethernet connection lost after few minutes since starting

[Victor Marin]

This is the same bug I notified at Bug #1770848 but with a more precise selection of (what I think it is) the package affected and a better description.

I made a few days ago a fresh install of the Kubuntu 18.04 LTS and it is most everything Ok, but -I think that- the network-manager has a problem.

In the last LTS version, Kubuntu 16.04, nor in any Linux version if I remember well, I never lost connection through Ethernet (the only Internet connection with our desktop PC), but the Bionic Beaver loses the connection every now and then, perhaps within few minutes or hours, but several times per day.

When the connection is lost, I note that it disappears any info even mention to any network into the network window and the network manager icon becomes red color.

Not matter if I unplug and then plug the ethernet cable again, the ethernet connection is not longer detected and only restarting the PC makes the connection to work again.

Incidentally, I also have noticed with this version of Kubuntu 18.04 that in my laptop there is also now a similar problem with the scanner: If I plug it in some USB port of the laptop once Kubuntu 18.04 is already running, it's not detected by Xsane. I have to plug it in before than pressing the power button or at the time of starting the OS, for the scanner to be detected by the scanning program (and then only works with Xsane, not if I use Simple Scan or Skanlite, even when it works under Xsane), as I said in the Bug #1771525 and, evenly, if I unplug the scanner cable from the USB port it is not detected anymore when plugging it again, and only restarting the laptop makes it to be detected.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: network-manager 1.10.6-2ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17
Uname: Linux 4.15.0-20-generic x86_64
ApportVersion: 2.20.9-0ubuntu7
Architecture: amd64
CurrentDesktop: KDE
Date: Thu May 17 08:24:23 2018
IfupdownConfig:
 # interfaces(5) file used by ifup(8) and ifdown(8)
 auto lo
 iface lo inet loopback
InstallationDate: Installed on 2018-05-11 (5 days ago)
InstallationMedia: Kubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
IpRoute:
 default via 192.168.1.1 dev enp0s7 proto static metric 100
 169.254.0.0/16 dev enp0s7 scope link metric 1000
 192.168.1.0/24 dev enp0s7 proto kernel scope link src 192.168.1.3 metric 100
IwConfig:
 enp0s7 no wireless extensions.

 lo no wireless extensions.
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
PciNetwork:

RfKill:

SourcePackage: network-manager
UpgradeStatus: No upgrade log present (probably fresh install)
nmcli-con:
 NAME UUID TYPE TIMESTAMP TIMESTAMP-REAL AUTOCONNECT AUTOCONNECT-PRIORITY READONLY DBUS-PATH ACTIVE DEVICE STATE ACTIVE-PATH SLAVE
 Conexión cableada 1 1cc37db8-0db8-3887-acf2-59fbbcd0cb1c ethernet 1526538083 jue 17 may 2018 08:21:23 CEST yes 4294967196 no /org/freedesktop/NetworkManager/Settings/1 yes enp0s7 activated /org/freedesktop/NetworkManager/ActiveConnection/1 --
nmcli-dev:
 DEVICE TYPE STATE DBUS-PATH CONNECTION CON-UUID CON-PATH
 enp0s7 ethernet connected /org/freedesktop/NetworkManager/Devices/2 Conexión cableada 1 1cc37db8-0db8-3887-acf2-59fbbcd0cb1c /org/freedesktop/NetworkManager/ActiveConnection/1
 lo loopback unmanaged /org/freedesktop/NetworkManager/Devices/1 -- -- --
nmcli-nm:
 RUNNING VERSION STATE STARTUP CONNECTIVITY NETWORKING WIFI-HW WIFI WWAN-HW WWAN
 running 1.10.6 connected started full enabled enabled enabled enabled enabled
---
ApportVersion: 2.20.9-0ubuntu7
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: nosotros 1116 F.... pulseaudio
 /dev/snd/controlC1: nosotros 1116 F.... pulseaudio
CurrentDesktop: KDE
DistroRelease: Ubuntu 18.04
HibernationDevice: RESUME=UUID=bb1531db-e7c0-48eb-a5b7-5afe3df47ba3
IfupdownConfig:
 # interfaces(5) file used by ifup(8) and ifdown(8)
 auto lo
 iface lo inet loopback
InstallationDate: Installed on 2018-05-11 (6 days ago)
InstallationMedia: Kubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
IpRoute:
 default via 192.168.1.1 dev enp0s7 proto static metric 100
 169.254.0.0/16 dev enp0s7 scope link metric 1000
 192.168.1.0/24 dev enp0s7 proto kernel scope link src 192.168.1.3 metric 100
IwConfig:
 enp0s7 no wireless extensions.

 lo no wireless extensions.
Lsusb:
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 Bus 002 Device 002: ID 04fc:0005 Sunplus Technology Co., Ltd USB OpticalWheel Mouse
 Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
MachineType: To Be Filled By O.E.M. To Be Filled By O.E.M.
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
Package: network-manager 1.10.6-2ubuntu1
PackageArchitecture: amd64
PciNetwork:

ProcFB: 0 radeondrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-20-generic root=UUID=d1d6ad93-b21c-43cd-8410-782414a5f935 ro quiet splash vt.handoff=1
ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17
RelatedPackageVersions:
 linux-restricted-modules-4.15.0-20-generic N/A
 linux-backports-modules-4.15.0-20-generic N/A
 linux-firmware 1.173
RfKill:

Tags: bionic
Uname: Linux 4.15.0-20-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
_MarkForUpload: True
dmi.bios.date: 07/17/2009
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: P1.50
dmi.board.name: N68-S
dmi.board.vendor: ASRock
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrP1.50:bd07/17/2009:svnToBeFilledByO.E.M.:pnToBeFilledByO.E.M.:pvrToBeFilledByO.E.M.:rvnASRock:rnN68-S:rvr:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.:
dmi.product.family: To Be Filled By O.E.M.
dmi.product.name: To Be Filled By O.E.M.
dmi.product.version: To Be Filled By O.E.M.
dmi.sys.vendor: To Be Filled By O.E.M.
nmcli-con:
 NAME UUID TYPE TIMESTAMP TIMESTAMP-REAL AUTOCONNECT AUTOCONNECT-PRIORITY READONLY DBUS-PATH ACTIVE DEVICE STATE ACTIVE-PATH SLAVE
 Conexión cableada 1 1cc37db8-0db8-3887-acf2-59fbbcd0cb1c ethernet 1526562681 jue 17 may 2018 15:11:21 CEST yes 4294967196 no /org/freedesktop/NetworkManager/Settings/1 yes enp0s7 activated /org/freedesktop/NetworkManager/ActiveConnection/1 --
nmcli-dev:
 DEVICE TYPE STATE DBUS-PATH CONNECTION CON-UUID CON-PATH
 enp0s7 ethernet connected /org/freedesktop/NetworkManager/Devices/2 Conexión cableada 1 1cc37db8-0db8-3887-acf2-59fbbcd0cb1c /org/freedesktop/NetworkManager/ActiveConnection/1
 lo loopback unmanaged /org/freedesktop/NetworkManager/Devices/1 -- -- --
nmcli-nm:
 RUNNING VERSION STATE STARTUP CONNECTIVITY NETWORKING WIFI-HW WIFI WWAN-HW WWAN
 running 1.10.6 connected started full enabled enabled enabled enabled enabled

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1771749

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Victor Marin (vic64)]

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[Victor Marin (vic64)]

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[Victor Marin (vic64)]

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[Victor Marin (vic64)]

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[Victor Marin (vic64)]

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[Victor Marin (vic64)]

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[Victor Marin (vic64)]

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[Victor Marin (vic64)]

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[Victor Marin (vic64)]

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[Victor Marin (vic64)]

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[Victor Marin (vic64)]

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[Victor Marin (vic64)]

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[Victor Marin (vic64)]

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[Victor Marin (vic64)]

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[Victor Marin (vic64)]

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[Victor Marin (vic64)]

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[Soltész András (soltesz-andras)]

This bug affects me as well, symptoms are exactly as the original poster writes.

Let me know if I need to collect information on my system.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Kai-Heng Feng (kaihengfeng)]

What's kernel version do you use in Xenial LTS?

[Victor Marin (vic64)]

I don't know which kernel version I did use in Xenial (initially I used the normal one, the kernel installed by default, but then I installed UKUU so couldn't remember, but I never had this problem with previous versions of Kubuntu nor any other flavor of Ubuntu nor in any Linux distro, for the case.

[Kai-Heng Feng (kaihengfeng)]

Can you attach dmesg when the ethernet went out?

[Victor Marin (vic64)]

Lately I not longer have noticed to lose the Internet connection; But if I unplug the ethernet cable and plug it again, then the Internet connection is not longer detected and only restarting the PC makes the connection to work again.

So I have unpluged the cable then plugged it again and it happens the same thing: the network manager icon in the system tray becomes red and it's not detected anymore. Only restarting the PC makes the connection to work.

I attach, both, dmesg outputs with and without Internet connection.

[Kai-Heng Feng (kaihengfeng)]

Do you see the issue on latest mainline kernel [0]?
If it still happen to mainline kernel, then find the first bad -rc kernel so we can start a kernel bisection.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.18-rc4/

[Victor Marin (vic64)]

AFAIK it not longer loses the Internet connection itself, but if I unplug the ethernet cable then the network manager becomes red and not any Internet connection is detected anymore when I re-connect the ethernet cable. Only a restart makes the network manager to get the normal color and to detect the Internet connection again.

On the other hand, I don't know what it means nor how to find the first bad -rc kernel.

This is the kernel version I have installed:

~$ uname -r
4.15.0-24-generic

I just did an:
# apt update

Then an:
# apt upgrade

And it tells that the system is up to date.

[Victor Marin (vic64)]

Concerning the issue that if I unplug the ethernet cable, the Network Manager icon in the systemtray becomes red color and when I plug it again, it remains red and no connection is detected, I have just confirmed that if I tick the allow automatic negotiation mark in the Wired tab of Edit Connections in Network Manager, then now when pluging the ethernet cable again, the Network Manager icon becomes normal color again, it detects the ethernet connection and it re-connects automatically Ok.

I don't know if this option was available before, as I didn't have to choose such option in previous versions of Kubuntu, but this was not a bug but a change in the options of Network Manager (and that it's not marked such option by default).

I attach you a screenshot for reference (in Spanish).

[Victor Marin (vic64)]

I not longer lost the ethernet connection, this far.

And concerning the issue that if I unplug the ethernet cable, the Network Manager icon in the systemtray becomes red color and when I plug it again, it remains red and no connection is detected: I confirmed that if I tick the allow automatic negotiation mark in the Wired tab of Edit Connections in Network Manager, then now when pluging the ethernet cable again, the Network Manager icon becomes normal color again, it detects the ethernet connection and it re-connects automatically Ok.

[Kent Lion (klsu)]

XUbuntu 18.04 has been doing this since I upgraded a few days ago. No error messages or any other sign that the Ethernet network connection has been dropped. I first notice it when I try to do something on the network and it times out. I haven't changed any network settings for over a year, but this never happened with Xenial LTS, and I haven't noticed any pattern to the occurrence vs what I happen to be doing at the time, so I can't reproduce it at will.

[José L. Domingo López (ubuntu-24x7linux)]

I have been affected by this one for a time now on a 18.04 LTS install on a laptop with both wired and wireless ethernet. Not a fresh install, but one that had been upgraded from earlier releases.

I have both Wireless and wired ethernet configured. NetworkManager is taking care of network IP address assignment, which is done dynamically on both cases through DHCP from the AP/router.

Every now and then, I get both network interfaces with no IP address assigned whatsoever. It may happen after resuming from suspend (laptop being powered down from hours to days) or while actively using the laptop. In all cases it seems NetworkManager service is still running and "dhclient" processes are up and running for the interfaces. For the latest time this has occured to me:
"""
# service NetworkManager status
● NetworkManager.service - Network Manager
   Loaded: loaded (/lib/systemd/system/NetworkManager.service; enabled; vendor preset: enabled)
   Active: active (running) since Fri 2018-11-16 21:31:31 CET; 4 days ago
     Docs: man:NetworkManager(8)
 Main PID: 845 (NetworkManager)
    Tasks: 5 (limit: 4915)
   CGroup: /system.slice/NetworkManager.service
           ├─ 845 /usr/sbin/NetworkManager --no-daemon
           ├─12154 /sbin/dhclient -d -q -sf /usr/lib/NetworkManager/nm-dhcp-helper -pf /run/dhclient-wlp3s0.pid -lf /var/lib/NetworkManager/dhclient-cef3df46-08a4-4e76-b0d8-3a2c21cd504e-wlp3s0.lease -cf /var/lib/NetworkManager/dhclient-wl
           └─23839 /sbin/dhclient -d -q -sf /usr/lib/NetworkManager/nm-dhcp-helper -pf /run/dhclient-enp0s25.pid -lf /var/lib/NetworkManager/dhclient-7d46e9cc-ee9c-366d-a025-73d355f9d046-enp0s25.lease -cf /var/lib/NetworkManager/dhclient-

# ps -efa | grep Netwo
root 845 1 0 nov16 ? 00:00:20 /usr/sbin/NetworkManager --no-daemon
root 1207 2521 0 14:13 pts/1 00:00:00 grep --color=auto Netwo
root 12154 845 0 nov20 ? 00:00:00 /sbin/dhclient -d -q -sf /usr/lib/NetworkManager/nm-dhcp-helper -pf /run/dhclient-wlp3s0.pid -lf /var/lib/NetworkManager/dhclient-cef3df46-08a4-4e76-b0d8-3a2c21cd504e-wlp3s0.lease -cf /var/lib/NetworkManager/dhclient-wlp3s0.conf wlp3s0
root 23839 845 0 nov20 ? 00:00:00 /sbin/dhclient -d -q -sf /usr/lib/NetworkManager/nm-dhcp-helper -pf /run/dhclient-enp0s25.pid -lf /var/lib/NetworkManager/dhclient-7d46e9cc-ee9c-366d-a025-73d355f9d046-enp0s25.lease -cf /var/lib/NetworkManager/dhclient-enp0s25.conf enp0s25
"""

For me, getting IP addresses assigned again to interfaces is as easy as running "service NetworkManager restart".

Last significant logs in /var/log/syslog prior to losing connectivity (IP address) on both network interfaces (wired "enp0s25" and wireless "wlp3s0") are as below:
"""
#### Wireless interface goes "timed out"
Nov 21 12:13:40 laptop NetworkManager[845]: <info> [1542798820.8236] connectivity: (wlp3s0) timed out
Nov 21 12:13:40 laptop avahi-daemon[841]: Withdrawing address record for 192.168.1.17 on wlp3s0.
Nov 21 12:13:40 laptop avahi-daemon[841]: Leaving mDNS multicast group on interface wlp3s0.IPv4 with address 192.168.1.17.
Nov 21 12:13:40 laptop avahi-daemon[841]: Interface wlp3s0.IPv4 no longer relevant for mDNS.

#### ...

[Kai-Heng Feng (kaihengfeng)]

Please follow Ubuntu wiki [1] and try mainline kernel.

[1] https://wiki.ubuntu.com/Kernel/MainlineBuilds