Fix IPv6 No Internet Access on Windows 10/11

Symptoms

• Network icon shows internet access but websites fail to load.
• IPv6 connectivity shows 'No internet access' in Network and Sharing Center.
• Ping to IPv6 addresses (e.g., google.com) fails while IPv4 works.
• ipconfig output shows an IPv6 address with 'Temporary' or 'Link-local' but no global address.

Root Causes

• Router or ISP does not support IPv6 or has it disabled.
• Windows IPv6 stack is corrupted or misconfigured.
• Network adapter driver is outdated or incompatible.
• Third-party firewall or VPN blocks IPv6 traffic.
• Incorrect DNS settings for IPv6.

Step-by-Step Fix

1. Check Router/ISP Support: Log into your router admin panel and verify IPv6 is enabled. Contact your ISP if unsure.
2. Disable IPv6 Temporarily: Go to Network and Sharing Center > Change adapter settings. Right-click your adapter > Properties. Uncheck 'Internet Protocol Version 6 (TCP/IPv6)'. Click OK and restart.
3. Reset Network Stacks: Open Command Prompt as Administrator. Run:

   netsh int ip reset

   netsh winsock reset

   Restart PC.
4. Renew IPv6 Address: In CMD:

   ipconfig /release6

   ipconfig /renew6

5. Update Network Driver: Open Device Manager > Network adapters. Right-click your adapter > Update driver. Choose 'Search automatically for drivers'.
6. Flush DNS: Run:

   ipconfig /flushdns

7. Set Google IPv6 DNS: In adapter properties, double-click IPv6. Use:

   Preferred DNS: 2001:4860:4860::8888

   Alternate DNS: 2001:4860:4860::8844

8. Disable IPv6 Privacy Extensions: Open CMD as Admin:

   netsh interface ipv6 set privacy state=disabled

Alternative Fixes

• Use Network Reset: Settings > Network & Internet > Advanced network settings > Network reset. This reinstalls network adapters.
• Disable IPv6 via Registry: Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters. Create DWORD DisabledComponents with value 0xFF. Reboot.
• Update Router Firmware: Check manufacturer website for latest firmware. Apply and test IPv6.

Prevention

• Keep Windows and network drivers updated.
• Use reliable DNS servers that support IPv6.
• Avoid using multiple VPNs or firewalls simultaneously.
• Periodically reset your network stack if issues recur.
• Ensure router firmware is current and IPv6 is properly configured.

Additional Tips

If after all steps IPv6 still fails, consider disabling IPv6 entirely (as a last resort) since most modern networks work well with IPv4. However, future-proofing by fixing IPv6 is recommended. For enterprise environments, consult your network administrator.