🔍 Problem Description#
Yesterday, I found that my laptop could not connect to the IPv6 internet:
Checking the network status, the local network shows IPv6 "No Internet Access"
In the command line, I queried ipconfig, and the IPv6 address acquisition was normal, starting with 240, but there was no network.
Then I searched for many methods online, such as CMD codes, modifying the registry, etc.:
✅ Reset TCP/IP stack (netsh int ip reset)
✅ Enable IPv6 privacy extension (netsh interface ipv6 set privacy state=enable)
✅ Update network card driver
✅ Disable IP Helper service
✅ Even reinstalled the system!
I spent five to six hours searching for answers and trying, but the problem persisted!
💡 The Culprit?#
Reinstalling initially solved the issue, but after installing software and completing the setup, it appeared again, which was really frustrating.
I eventually discovered that the culprit was software like "accelerators"! Before realizing this issue, I had also turned off the accelerator, but it still had subprocesses running in the background. I had followed methods found online and restarted the computer many times, but it still did not recover.
The accelerator itself does not have permission to start with the system. — However, due to the characteristics of Windows 10 and above, if the process of this software is running in the background before shutdown, it will still be there after a restart.
Later, I saw a blogger in Microsoft's official Q&A mention that he had opened Clash, and I immediately thought of it, so I terminated it in the background. The IPv6 internet access was immediately restored!
📌 Cause Analysis#
Some accelerators/VPN software will:
- Modify the system network stack (such as installing virtual network cards, hijacking DNS)
- Run in the background (even if the software interface is closed)
- Interfere with IPv6 routing (especially TAP-Windows type drivers)
The "Fast Startup" feature of Windows 10/11 (Hybrid Boot) causes the system not to completely shut down the kernel, leading to residual drivers/services from these software, affecting network configuration.
🎯 Conclusion#
If you encounter "IPv6 No Internet Access" and have tried various methods without success, be sure to check if there are any accelerators, VPNs, or proxy software running in the background!