For several weeks, my Windows 11 PC has lost internet access through Ethernet at almost exactly 1:00 AM. The Ethernet adapter remains enabled and shows network activity, but it has no internet connection. Wi-Fi continues working normally, and the wired connection is back by morning without me changing anything.
I have updated and reinstalled the Realtek Gaming 2.5GbE Family Controller driver, checked the cables, run network-reset commands, toggled the adapter, checked power-saving settings, and completely reset Windows network settings. Windows Defender is the only security software installed, and I do not use a VPN or other connection-management software.
The adapter reports DHCP enabled, a 24-hour lease, a 1500 MTU, and a 1000/1000 Mbps link. IPv4 shows connected to the local network while IPv6 reports an unknown network. Other wired computers in the house do not appear to lose connectivity at the same time. The network equipment includes a TP-Link router and another small box that I did not install, so I am not sure which device handles the Ethernet connection.
What could cause one wired connection to stop working on a predictable schedule while Wi-Fi remains available, and what should I check first?
5 Answers
A useful test is to run `ipconfig /all` while the failure is happening and compare it with the working state. Check whether the Ethernet adapter still has the expected IPv4 address, default gateway, and DNS servers. Then try pinging the gateway first, followed by a public IP such as 1.1.1.1. If the gateway fails, the problem is local to the PC, cable, port, or router; if the gateway works but public access fails, investigate routing or DNS.
Try isolating the hardware. A USB-to-Ethernet adapter or dock is a quick test, and you can also move the cable to another router port. If the replacement adapter works through the overnight period, the Realtek controller, its driver, or the motherboard firmware is probably involved. If both adapters fail at the same time, focus on the router, gateway, or a scheduled access rule.
The small black box may be a modem, switch, or another network gateway. Check its status and event logs, and ask the internet provider whether it performs nightly maintenance or firmware updates. Some providers schedule modem resynchronization overnight, although that would usually affect Wi-Fi too unless the wired path is being handled differently.
The exact timing strongly suggests a scheduled rule rather than a random driver failure. Check the TP-Link router and any upstream modem or gateway for parental controls, access schedules, device bedtime rules, or scheduled maintenance. Look for your PC by its device name or MAC address. Since other wired computers stay online, a rule targeting only this device is more likely than a full internet outage.
Also check Windows Task Scheduler, scheduled update or maintenance jobs, and the active power plan for anything that could disable or restart the network adapter overnight. Event Viewer under Windows Logs > System may show a network adapter, DHCP, or driver event around 1:00 AM. The fact that the adapter still shows traffic does not prove it has a valid route to the internet.
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