No internet after upgrade from 16.04 to 18.04

No internet after upgrade from 16.04 to 18.04

After the upgrade I noticed that I dont have internet access. The wired network and the wifi settings looked good, but it didnt work. After the login the system always switched itself into airplane mode. I tethered the network via USB and Bluetooth by my mobile but they also didnt work.

the ORIGIN of the solution if the etcresolv.conf is empty but you can ping 8.8.8.8 echo nameserver 8.8.8.8 sudo tee etcresolv.conf devnull if the etcresolvconfresolv.conf.dhead is empty then you have to repeat the command above after every restart except you do this: echo nameserver 8.8.8.8 sudo tee -a etcresolvconfresolv.conf.dhead devnull then you have to restart the resolvconf and the networking sudo systemctl enable resolvconf sudo systemctl start resolvconf sudo etcinit.dnetworking restart

I had the same problem after upgrading from 18.10 to 18.04. I tried the solution proposed here, but it doesnt seem to work for me. - I have nameserver 8.8.8.8 in my etcresolv.conf - I restarted networking as indicated above - my etcnetworkinterfaces says auto lo iface lo inet loopback - ifconfig-a says interfaces called enp0s25 lo and wlp2so are all up I still have no internet, though networking says it is connected. Im out of my depth here...