Ethernet Connection Has No Valid IP Configuration or DHCP Server
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MellowCedar47
After my provider made changes to the service, the Wi-Fi network was reset. Most devices reconnected normally, and one of my Ethernet-connected PCs works without any issues. However, the other PC cannot get online and reports that it has no valid IP configuration. Running ipconfig shows no default gateway and no DHCP server, and the router's device list shows the computer with a blank host name and device type. I replaced the Ethernet cable, tried every router port, confirmed IPv4 and DNS are set to obtain addresses automatically, updated the LAN drivers, and uninstalled and reinstalled the adapter through Device Manager. Nothing has helped. What else should I check?
Answers
The blank DHCP and gateway fields mean the PC is not completing DHCP at all. After confirming the adapter and cable, reset Windows networking from an elevated Command Prompt with netsh winsock reset and netsh int ip reset, then restart the computer. If that changes nothing, check for security software or a manually configured static address, and test with a temporary USB Ethernet adapter to determine whether the onboard network hardware has failed.
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Since another computer works through the same router, the issue is probably isolated to this PC rather than the provider or router. Verify that the Ethernet adapter is enabled and that IPv4 is configured to obtain both an IP address and DNS automatically. Then run ipconfig /release followed by ipconfig /renew. If the computer still receives no gateway or DHCP server, uninstall the Ethernet adapter in Device Manager and reboot so Windows can detect it again.
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Try ruling out the physical connection even though the cable is new. Test a different LAN port on the router and, if possible, connect the problem PC to another network or use a USB Ethernet adapter. If it works elsewhere, the computer’s built-in network port or the router port may be the problem. If it fails everywhere, the adapter or Windows networking stack is more likely at fault.
MellowCedar47: I tested every port on the router and none of them worked with this PC, while the other PC continues to connect normally.
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MellowCedar47: I confirmed the automatic IPv4 and DNS settings, and the adapter is enabled. I also tried removing the adapter and rebooting, but it still does not receive an address.