For some reason the default driver for the Realtek RTL8111/8168/8411 wired Ethernet controller in the Lenovo IdealPad L340-15IHR will not work under Ubuntu 22.04. This happens with both a clean install and upgrading from Ubuntu 21.04/21.10. The solution is to install the
r8168-dkms driver and reboot.
***EDIT: I should have added blacklist the r8169 driver (it seems list like this driver is poorly implemented):
sudo sh -c 'echo blacklist r8169 >> /etc/modprobe.d/blacklist.conf'
And, install the r8168 driver:
sudo apt-get install -y r8168-dkms