There are a few possibilities for bad internet.
- Ethernet cable plugged into wrong port
- DNS improperly configured
Ethernet cable plugged into wrong port
Look at the rear of the machine. Ensure the Ethernet cable is plugged into one of the Ethernet ports circled in the image below. The third, upper-left Ethernet port will not work, as it is for IPMI only.
DNS improperly configured
To resolve this:
sudo ln -s /run/systemd/resolve/stub-resolv.conf /etc/resolv.conf
systemctl restart resolvconf
And you should get internet.