I have a port (all wiring is T568A) to my son’s room. My work laptop connects fine. No issues. I can see IPV4 and 6 addresses, DNS etc. His desktop will not connect. Only shows IP6. No IP4, no DNS. We have tried swapping the cable to his desktop and it still makes no different.
Any ideas where to start troubleshooting?
I’m also having a very similar issue. Desktop stopped working over Ethernet, cable works on another desktop as well as a laptop. It usually gets an ipv6 address, even though ipv6 is disabled at the router.