Diagnosing and Resolving Network Issues in Windows

Introduction: Why Your Windows Network "Gets Sick"

Network issues in Windows often appear suddenly: internet disappears while Wi-Fi is connected, the "No network access" or "Unidentified network" icon appears. The causes can vary—from a simple router failure to driver conflicts or firewall blocking.

In this guide, we'll walk through a standard diagnostic algorithm that solves 90% of cases of lost network connectivity in Windows 10 and 11. We'll start with the simplest actions (restarting hardware) and move up to resetting TCP/IP stacks and updating drivers. All commands and instructions have been tested on current versions of Windows.

💡 Tip: Perform the steps sequentially. After each step, check if internet access has been restored. Often, the second or third step does the trick.

Step 1: Physical Layer and Hardware Restart

Before digging into OS settings, make sure the problem isn't at the cable, router, or Wi-Fi module level.

1.1. Check the Cable and Wi-Fi

• Wired connection: Check if the Link indicator lights up on the network card and router. Try a different cable or router port.
• Wireless connection: Ensure you're connected to the correct network (not a guest network with restrictions). Check the signal strength. If the signal is weak, move closer to the router.

1.2. Restart the Router and Computer

This is standard but often ignored. Restarting clears the router's cache and restarts the DHCP server that assigns IP addresses.

1. Shut down the computer (completely, not sleep mode).
2. Unplug the router's power for 30 seconds.
3. Plug in the router and wait for it to fully boot (usually 1-2 minutes).
4. Turn on the computer.

After this, check if access has returned. If not—move to Step 2.

Step 2: Windows' Built-in Network Troubleshooter

Windows includes a troubleshooter that can automatically fix common errors: missing IP address, DHCP problems, incorrect adapter settings.

How to launch:

1. Open Windows Settings (Win + I).
2. Go to Network & Internet → Advanced network settings (or Network and Sharing Center in older versions).
3. Click Network troubleshooter.
4. Select Internet and run the tool.

The troubleshooter will check:

• Network adapter functionality.
• IP address presence and gateway correctness.
• DNS settings.
• Access to time servers (NTP).

If the tool finds and fixes an issue, you'll see a notification. If not—proceed to manual methods.

⚠️ Important: The built-in troubleshooter doesn't always find complex issues (like driver conflicts or firewall blocks). So even if it runs successfully, still check your internet access.

Step 3: Reset Network Settings via Command Prompt

This step restores default settings for Windows network components: TCP/IP, Winsock, DNS cache. Does not delete personal data or installed programs.

3.1. Launch Command Prompt as Administrator

• Press Win + X and select Command Prompt (Admin) or Windows PowerShell (Admin).
• If UAC appears, click Yes.

3.2. Run Commands in Order

# 1. Reset Winsock (Windows network API)
netsh winsock reset

# 2. Reset TCP/IP configuration
netsh int ip reset

# 3. Flush DNS cache
ipconfig /flushdns

# 4. Release and renew IP address (restart DHCP)
ipconfig /release
ipconfig /renew

3.3. Restart the Computer

After running all commands, restart your PC. This applies the changes to the stack settings.

After reboot, check connectivity. If the problem persists—move to drivers.

Step 4: Update or Reinstall Network Adapter Drivers

Outdated or corrupted drivers are a common cause of network failures after a Windows update or third-party software installation.

4.1. Check Current Driver in Device Manager

1. Press Win + X → Device Manager.
2. Expand Network adapters.
3. Right-click your adapter (e.g., Realtek PCIe GbE Family Controller or Intel(R) Wi-Fi 6 AX201) → Properties.
4. Go to the Driver tab → check Driver Version and Date.

4.2. Update Options:

• Automatically via Device Manager: In the adapter's context menu, select Update driver → Search automatically for updated driver software.
• Manually from manufacturer's site:
  • For laptops: go to the manufacturer's support site (Dell, HP, Lenovo, etc.), enter your model, and download the network driver.
  • For motherboards: go to the motherboard manufacturer's site (ASUS, Gigabyte, MSI) and download the driver for your model.
  • For a standalone Wi-Fi/network adapter (e.g., from TP-Link): find the model number on the device and download the driver from the official site.

4.3. Reinstall the Driver

If updating didn't help:

1. In Device Manager, right-click the adapter → Uninstall device.
2. Check the box "Delete the driver software for this device" if available.
3. Click Uninstall.
4. Restart the computer. Windows will automatically install a generic driver. Then manually install the fresh driver (Step 4.2).

⚠️ Important: If you have multiple adapters (e.g., Ethernet and Wi-Fi), check both. Sometimes the issue is with one while you're testing the other.

Step 5: Check Firewall and Antivirus

Antivirus programs and firewalls (including third-party ones) can block network traffic by mistake.

5.1. Temporarily Disable Windows Firewall

1. Open Control Panel → System and Security → Windows Defender Firewall.
2. On the left, select Turn Windows Defender Firewall on or off.
3. For both networks (Private and Public), check Turn off Windows Defender Firewall.
4. Click OK.

5.2. Disable Third-Party Antivirus/Firewall

• Find your antivirus icon in the system tray (near the clock) (Kaspersky, ESET, Avast, etc.).
• Right-click → Manage or Settings → find Real-time protection or Firewall and disable for 5-10 minutes.

5.3. Check Internet Access

If the network works after disabling—the issue is in your security settings. You need to add exceptions for:

• svchost.exe (Windows services)
• System (Windows process)
• Browsers (chrome.exe, firefox.exe, etc.)

Re-enable your firewall and antivirus and configure rules in their interface. If you don't know how—contact your antivirus support.

Additional Methods (If Nothing Helped)

6.1. Check and Change DNS Servers

Sometimes the issue is with your ISP's DNS servers. Switch to public ones from Google or Cloudflare:

1. Open Control Panel → Network and Internet → Network and Sharing Center.
2. On the left, click Change adapter settings.
3. Right-click your active adapter → Properties.
4. Select Internet Protocol Version 4 (TCP/IPv4) → Properties.
5. Check Use the following DNS server addresses:
   • Preferred: 8.8.8.8
   • Alternate: 8.8.4.4 (or 1.1.1.1 and 1.0.0.1 from Cloudflare)
6. Click OK → close windows.

6.2. Check Proxy Settings

Incorrect proxy settings can block access:

1. Open Settings (Win + I) → Network & Internet → Proxy.
2. Under Manual proxy setup, ensure Use a proxy server is off.
3. Under Automatic proxy setup, you can leave Automatically detect settings on.

6.3. Log Analysis via PowerShell

Launch PowerShell as administrator and run:

# Check network adapter status
Get-NetAdapter | Format-Table Name, Status, LinkSpeed

# Check IP configuration
Get-NetIPConfiguration

# Check routing
Get-NetRoute -DestinationPrefix "0.0.0.0/0"

# Check if DNS works (replace example.com with any domain)
Test-NetConnection -ComputerName example.com -Port 53

Pay attention to Status (should be Up), IPv4Address (should have an address, not 169.254.x.x), IPv4DefaultGateway (gateway should be listed).

What to Do If No Step Helped?

If you've completed all steps and internet still doesn't work:

1. Connect to a different network (e.g., a mobile hotspot on your phone). If internet works there—the problem is with your router or ISP. Reset the router to factory settings or call your ISP support.
2. Check for hardware issues: if possible, install the network card in another computer or use a USB-Ethernet adapter. If another PC with the same cable has internet—the problem is your network card (may need replacement).
3. Create a new Windows user account and test the network there. If it works in the new account—the problem is in your current user profile (possibly corrupted settings or group policies).
4. Perform a system restore to a point when the network was still working.