A non-working LAN connection is usually fixable with a few checks and simple commands — the most common causes are a bad cable, disabled or misconfigured network adapter, driver or router problems, or corrupted network settings. If your LAN connection doesn’t work in Windows 10, this article walks you through the likely causes and exact, step-by-step fixes so you can get wired networking working again.
You’ll learn quick checks to isolate the problem, detailed Windows 10 steps (menus and commands), and tips to prevent future issues.
Key Takeaway
The fastest reliable fix is to verify physical connections and adapter status, then reset the network stack (run ipconfig /release, ipconfig /renew, ipconfig /flushdns, netsh winsock reset, netsh int ip reset) from an elevated Command Prompt — this resolves most software-related LAN outages.
Quick Fix Guide
Quick Fix Guide
| Reason for the Problem | Quick Solution |
|---|---|
| 1. Faulty or unplugged Ethernet cable | Replace or reseat the cable and try a different port. |
| 2. Network adapter is disabled | Enable the adapter in Network Connections. |
| 3. Incorrect (static) IP or gateway | Set IPv4 to obtain IP and DNS automatically or correct values. |
| 4. Outdated/corrupt network driver | Update or reinstall the adapter driver via Device Manager. |
| 5. Router/modem issues | Power-cycle router/modem and check link lights. |
| 6. Windows network services stopped | Ensure DHCP Client, DNS Client, and related services are running. |
| 7. Power-saving settings turn off adapter | Disable power-saving for the network adapter in Device Manager. |
| 8. Firewall or security software blocking LAN | Temporarily disable firewall/antivirus or adjust rules. |
| 9. DNS resolution problems | Flush DNS and set a reliable DNS (e.g., 1.1.1.1 or 8.8.8.8). |
| 10. Duplex/speed mismatch | Set adapter Speed & Duplex to Auto Negotiation or match router. |
| 11. Corrupted network stack | Reset network stack with netsh and winsock commands. |
| 12. Hardware failure or BIOS disabled NIC | Test with another PC or USB Ethernet adapter; enable NIC in BIOS/UEFI. |
Detailed Fixes for “LAN connection doesn’t work in Windows 10”
1. Faulty or unplugged Ethernet cable
Why it causes the problem
- A broken cable, loose connector, or bad switch/router port prevents physical link between PC and network.
Step-by-step solution
- Verify physical connection: ensure the Ethernet cable is securely attached to the PC and router/switch. Look for link/activity LEDs near the port.
- Swap the cable with a known-good cable to rule out damage.
- Try a different port on the router or switch.
- If available, connect the PC to another device (another PC or laptop) using the same cable to confirm whether the cable or port is the issue.
Notes/tips
- Use Cat5e or Cat6 cable for gigabit connections. Bent pins inside RJ45 can break the connection.
2. Network adapter is disabled
Why it causes the problem
- If the adapter is turned off, Windows cannot use it to access the network.
Step-by-step solution
- Open Settings > Network & Internet > Status.
- Click Change adapter options.
- Right-click the Ethernet adapter (usually named Ethernet) and choose Enable if it’s disabled.
- Alternatively, open Control Panel > Network and Sharing Center > Change adapter settings, right-click adapter and enable.
Notes/tips
- If the adapter toggles repeatedly between enable/disable, try updating the driver or checking Event Viewer for errors.
3. Incorrect (static) IP or gateway
Why it causes the problem
- Wrong IP address, subnet mask, or gateway prevents communication with the router or internet (IP conflict or wrong network).
Step-by-step solution
- Open Settings > Network & Internet > Ethernet > Change adapter options.
- Right-click your Ethernet adapter and choose Properties.
- Select Internet Protocol Version 4 (TCP/IPv4) and click Properties.
- Choose Obtain an IP address automatically and Obtain DNS server address automatically, then click OK.
- If you require a static IP, confirm values with your network admin and enter correct IP address, Subnet mask, and Default gateway. Enter DNS servers (e.g., 8.8.8.8, 1.1.1.1).
Commands to refresh
- Open Command Prompt (Admin) and run:
- ipconfig /release
- ipconfig /renew
- ipconfig /flushdns
Notes/tips
- If your router uses a different subnet (e.g., 10.0.x.x), make sure static IP matches that range.
4. Outdated or corrupt network drivers
Why it causes the problem
- Bad or incompatible drivers can break adapter functionality after updates or driver corruption.
Step-by-step solution
- Open Device Manager (right-click Start and choose Device Manager).
- Expand Network adapters and find your Ethernet adapter.
- Right-click it and choose Update driver > Search automatically for drivers.
- If automatic update fails, choose Uninstall device, check Delete the driver software for this device if present, then reboot — Windows will attempt to reinstall the driver.
- For manufacturer drivers, download the latest driver from the PC or NIC manufacturer’s website and install manually using Browse my computer for drivers.
Notes/tips
- Keep a backup of known-good drivers. Use a USB stick if reinstalling on a machine without internet.
5. Router/modem issues
Why it causes the problem
- Router or modem faults (firmware bugs, overloaded CPU, broken DHCP) can stop wired clients from connecting.
Step-by-step solution
- Power-cycle the router/modem: unplug power for 30 seconds, then plug back in.
- Check router status page via another device (if Wi‑Fi works) and confirm LAN status.
- Ensure cables from modem to router and router to switch/PC are properly seated.
- Update router firmware following manufacturer instructions.
- If only one PC is affected, test PC on another LAN port; if multiple clients are down, contact ISP or factory reset the router as last resort.
Notes/tips
- Always back up router settings before factory reset.
6. Windows network services stopped
Why it causes the problem
- Essential services like DHCP Client, DNS Client, or Network Connections not running break IP assignment and name resolution.
Step-by-step solution
- Press Win + R, type services.msc and press Enter.
- Check these services: DHCP Client, DNS Client, Network Connections, Network List Service, Network Location Awareness.
- For any stopped service, right-click and choose Start, and set Startup type to Automatic.
- Restart the computer.
Notes/tips
- Some third-party apps may change service configuration; check Event Viewer for related errors.
7. Power-saving settings turn off adapter
Why it causes the problem
- Windows may disable the adapter to save power, especially on laptops, interrupting LAN connectivity.
Step-by-step solution
- Open Device Manager > Network adapters.
- Double-click your Ethernet adapter, go to Power Management tab.
- Uncheck Allow the computer to turn off this device to save power and click OK.
- Also check Power Options: Control Panel > Power Options > Change plan settings > Change advanced power settings > PCI Express > Link State Power Management — set to Off.
Notes/tips
- On laptops, switching from battery to plugged-in mode can change behavior.
8. Firewall or security software blocking LAN
Why it causes the problem
- Overzealous firewall or security suite rules can block LAN traffic or DHCP.
Step-by-step solution
- Temporarily disable Windows Firewall: Start > Windows Security > Firewall & network protection > Domain/Private/Public network > Turn off Windows Defender Firewall (for testing only).
- If you use third-party security software, open its UI and temporarily disable its network/firewall features.
- If disabling fixes LAN, reconfigure firewall rules to allow traffic from your LAN subnet, or create an exception for the adapter.
- Re-enable firewalls after testing.
Notes/tips
- Never leave firewall disabled; only use for short tests. Document any rule changes.
9. DNS resolution problems
Why it causes the problem
- If DNS fails, you can still ping IP addresses but not resolve hostnames or websites.
Step-by-step solution
- Open Command Prompt (Admin) and run ipconfig /flushdns to clear DNS cache.
- Change DNS servers: Settings > Network & Internet > Ethernet > Change adapter options > Properties > Internet Protocol Version 4 (TCP/IPv4) > Properties, set Preferred DNS server to 8.8.8.8 and Alternate to 1.1.1.1.
- Test connectivity: ping 8.8.8.8 (tests IP-level reachability) and ping www.google.com (tests DNS).
Notes/tips
- Some corporate networks require internal DNS servers — consult IT before changing DNS.
10. Duplex/speed mismatch
Why it causes the problem
- If the NIC and switch/router use incompatible speed/duplex settings (e.g., one is forced to 100Mbps full duplex, the other auto), throughput problems or connectivity loss occur.
Step-by-step solution
- Open Device Manager > Network adapters, double-click adapter and go to Advanced tab.
- Find Speed & Duplex or similar and set to Auto Negotiation or match the router’s port speed (e.g., 100 Mbps Full Duplex).
- If you change the setting, restart the adapter or machine.
Notes/tips
- Gigabit links require all four wire pairs; damaged cable can force lower speeds.
11. Corrupted network stack
Why it causes the problem
- Network settings, Winsock catalog, or TCP/IP stack corruption can stop all network communication.
Step-by-step solution
- Open Command Prompt (Admin).
- Run the following commands one by one:
- netsh winsock reset
- netsh int ip reset
- ipconfig /flushdns
- ipconfig /release
- ipconfig /renew
- Reboot the PC.
- If problems persist, in an elevated prompt run netcfg -d (this removes and reinstalls all networking components; note this may remove VPN or virtual adapters).
Notes/tips
- Use netcfg -d only if other resets fail; have driver installers ready.
12. Hardware failure or BIOS/UEFI disabled NIC
Why it causes the problem
- The NIC itself may be damaged, or the onboard LAN adapter disabled at the firmware level.
Step-by-step solution
- Check Device Manager for error icons (yellow triangle) next to the adapter.
- Test the PC with a USB-to-Ethernet adapter or a PCIe NIC; if that works then onboard NIC may be defective.
- Reboot and enter BIOS/UEFI (often Del, F2, or F10 during boot) and check Integrated Peripherals or Onboard Devices to ensure LAN is enabled.
- If onboard NIC is faulty and under warranty, contact manufacturer for repair; otherwise use an add-on NIC.
Notes/tips
- If NIC fails intermittently, thermal or motherboard issues may also be involved.
When to contact your ISP or a technician
- If multiple devices (wired and wireless) are offline, test whether the router/modem shows an upstream (WAN) connection; contact your ISP if WAN is down.
- If only your PC is affected after trying the software fixes above, contact a technician or the PC manufacturer — especially for suspected hardware failure.
- Provide the technician with results of tests you ran (ping to gateway, ipconfig output, link light status) to speed diagnosis.
FAQ
Q: Can Windows Update break my LAN connection?
A: Yes — driver updates or network-related Windows updates occasionally introduce issues; rolling back the adapter driver in Device Manager or uninstalling a recent update can help.
Q: How can I tell if the NIC is dead?
A: Look for no link/activity LEDs, Device Manager errors, inability to obtain IP on multiple cables/ports, and a USB Ethernet adapter working while onboard NIC doesn’t.
Q: Should I disable IPv6?
A: Generally no — leave IPv6 enabled unless you have a specific reason; disabling it rarely fixes common LAN connection problems and can cause issues with modern networks.
Q: How do I prevent this happening again?
A: Keep drivers and firmware updated, avoid power-saving on NICs if you rely on stable LAN, use quality cables/switches, and create a restore point before major updates.
Q: Can a VPN or virtual adapter break my LAN?
A: Yes — some VPN clients or virtual network adapters can change routing/DNS. Temporarily uninstall or disable them to see if connectivity returns.
Conclusion
Most LAN outages in Windows 10 are caused by physical issues, adapter settings, driver problems, or a corrupted network stack — checking the cable and adapter status, updating drivers, and resetting the network stack resolve the majority of cases. If your LAN connection doesn’t work in Windows 10, follow the steps above in order and contact your ISP or a technician only after these troubleshooting steps.
