My Windows 11 PC suddenly stopped detecting internet over Ethernet. The same cable and router work normally with my laptop, and the Ethernet port lights are on. Restarting the router and PC, resetting network settings, reinstalling the LAN drivers, manually configuring IPv4, and changing DNS servers did not help. A wired internet connection shared from my phone also shows "No internet access."
The most unusual part is that the DHCP Client and DNS Client services will not start and return Error 5 (Access Denied), even though they are set to start automatically. The RPC service appears to be running, but commands such as ipconfig /release report that RPC is unavailable. I'm using a Gigabyte H610M K DDR4 motherboard. I also previously removed a WLAN adapter and had a Cloudflare VPN that seemed to malfunction, but removing the VPN did not restore connectivity.
2 Answers
Error 5 when starting DHCP usually points to corrupted permissions on the service rather than a bad Ethernet cable or DNS setting. Open Command Prompt as administrator and reset the DHCP Client security descriptor with: sc sdset dhcp D:(A;;CCLCSWRPWPDTLOCRRC;;;SY)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BA)(A;;CCLCSWLOCRRC;;;AU)(A;;CCLCSWRPWPDTLOCRRC;;;PU)
Do the same for the DNS Client service: sc sdset dnscache D:(A;;CCLCSWRPWPDTLOCRRC;;;SY)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BA)(A;;CCLCSWLOCRRC;;;AU)(A;;CCLCSWRPWPDTLOCRRC;;;PU)
Restart the computer afterward and check whether both services can start. Also verify that Remote Procedure Call is running in Services. If this does not resolve the issue, run sfc /scannow followed by DISM /Online /Cleanup-Image /RestoreHealth from an elevated Command Prompt, since corruption affecting several core networking services may indicate a broader Windows problem.
Check Reliability Monitor for errors recorded immediately before the network stopped working. It may reveal whether a VPN or another recently installed program damaged Windows networking components. Since the same cable works on another device and phone tethering fails too, the router and cable are unlikely to be the cause; the broken Windows services are the more important clue.
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