Ethernet not working in Ubuntu 16.04 (works in Windows) with RTL8111/8168/8411
Download these files and copy them to your Ubuntu Home folder.
http://mirrors.kernel.org/ubuntu/pool/universe/r/r8168/r8168-dkms_8.041.00-1_all.deb http://mirrors.kernel.org/ubuntu/pool/main/d/dkms/dkms_2.2.0.3-2ubuntu11_all.deb
Then run in a terminal
sudo dpkg -i dkms*.deb r8168*.deb
and reboot.