Ethernet not getting Internet connection

I rebooted my Bigpipe Modem/Router this week (standard Huawei HG659) and ever since then ethernet/LAN connections have been unable to connect to the internet.

WIFI is getting Internet (which is how I am writing this). Ethernet connects but reports an "Unidentified network with no Internet Access"

Have tried two different computers (one linux, one windows 10), Lan cables, ports on the Router - no difference.

When on the WIFI, I can connect to the Router and it shows the computer as connected via LAN.

So connection is working. Router is working and providing internet over WIFI, but I can't get internet over the LAN cable.

Stumbling around through the configurations I have noticed the following difference between the connections: Wifi has IPv6 and IPV4 DNS servers listed. Ethernet has only IPv6

So to resolve the issue I either need to get IPV4 available via ethernet again, or configure my computer for IPv6 internet addresses.I'd also like to understand what happened here, but that might not be possible :-)Either the router reboot, or maybe a sneaky windows update changed settings?

Any pointers as to where to switch these things on/off? On the modem? In windows?

thanks,

evnafets