Erratic ethernet connectivity and icon

[Aurosutru]

Ubuntu 18.04.4 LTS

Installed: 1.10.6-2ubuntu1.4
  Candidate: 1.10.6-2ubuntu1.4
  Version table:
 *** 1.10.6-2ubuntu1.4 500

Expected behavior is a stable high-speed internet connection when usb tethering with an Android phone.

Instead, for the past three months, since covid slowed down internet connectivity on Jio telecom in India, my Ubuntu internet connectivity has become erratic. In the early morning before 6 AM when I tether an Android phone to my laptop the internet connectivity indicator in the upper right-hand corner of the desktop shows the normal three boxes in a triangle and has decent speed. As network traffic increases the indicator turns to three gray boxes with a question mark in the middle and connectivity speed remains decent for a few websites, such as YouTube, Google Search and some others, but connectivity stops for most websites. Chromium, Vivaldi and Firefox browsers show the following error for such sites: “This site can’t be reached. askubuntu.com’s server IP address could not be found.”

Oddly, in tri-booted Win 10 all websites open reliably 24/7, though sometimes at slow speeds. In Fedora 31 on the same hardware the behavior is identical to Ubuntu. I’ve tried changing the DNS settings in Ubuntu to use Cloud Flare, Google and even the DNS settings in Windows, but to no avail. On Ask Ubuntu there were no helpful comments except a suggestion to file a bug report.

Ideally, connectivity without "unable to connect" errors on most websites should be available always.

BTW, when I allowed data to be collected for this bug report it was in the early morning, so the connection was working properly and the network icon was the normal three boxes in a triangle with decent speed. If need be, I can send more information later when the "unable to connect" errors occur from Windows 10, or via email, which always works.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: network-manager 1.10.6-2ubuntu1.4
ProcVersionSignature: Ubuntu 4.15.0-106.107-generic 4.15.18
Uname: Linux 4.15.0-106-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.20.9-0ubuntu7.15
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Sat Jun 20 06:49:22 2020
IfupdownConfig:
 # interfaces(5) file used by ifup(8) and ifdown(8)
 auto lo
 iface lo inet loopback
InstallationDate: Installed on 2018-08-25 (664 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
IpRoute:
 default via 192.168.137.129 dev enp0s20u1 proto dhcp metric 100
 169.254.0.0/16 dev enp0s20u1 scope link metric 1000
 192.168.137.0/24 dev enp0s20u1 proto kernel scope link src 192.168.137.9 metric 100
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
RfKill:
 0: phy0: Wireless LAN
  Soft blocked: no
  Hard blocked: no
SourcePackage: network-manager
UpgradeStatus: No upgrade log present (probably fresh install)
nmcli-dev:
 DEVICE TYPE STATE DBUS-PATH CONNECTION CON-UUID CON-PATH
 enp0s20u1 ethernet connected /org/freedesktop/NetworkManager/Devices/4 Wired connection 3 d70d6035-59a6-34c1-a00a-d222c65aef1c /org/freedesktop/NetworkManager/ActiveConnection/1
 wlp2s0 wifi disconnected /org/freedesktop/NetworkManager/Devices/3 -- -- --
 enp3s0f2 ethernet unavailable /org/freedesktop/NetworkManager/Devices/2 -- -- --
 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

[Sebastien Bacher (seb128)]

Thank you for your bug report, could you add your 'journalctl -b 0' after seeing the issue?

[Aurosutru (2fullnesses)]

Here is the result of journalctl -b 0 while the problem is manifest.