🔍 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"
I queried ipconfig in the command line, 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 extensions (netsh interface ipv6 set privacy state=enable)
✅ Update network card drivers
✅ Disable IP Helper service
✅ Even reinstalled the system!
I spent five to six hours searching for answers and trying, but the problem persisted!
💡 Culprit?#
After reinstalling, it was resolved at first, but after installing software and completing the setup, it appeared again, which was really frustrating.
I eventually discovered: 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 tried many methods found online and restarted the computer multiple times, but it still did not recover.
The accelerator itself does not have startup permissions. — 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)
- Keep running 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 also 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!