6to4 isatp tunnel problem windows VISTA & 7

The PC or laptop may appear to be very slow and CPU is at 100% most of the time. When you check in taskmanager (after selecting show processes from all users) 1 or more svchost.exe processes are hogging CPU. When you right click the svchost.exe and choose “go to service” you find oud that it is 1 of the following services:
– wudfsvc
– DcomLaunch
– PlugPLay

Open up a Command prompt (type cmd in the start – search field) and type in ipconfig to see if there a lot of tunnel adapters present. Normally you see only 1 or maximum 4 and then a local area network and perhaps a wireless adapter. If you have dozens of tunnel adapters, then this bug is effecting you.

Too many tunnel adapters in IPCONFIG

Too many tunnel adapters in IPCONFIG

To solve this execute the following:
Open up a Command prompt (CMD) but right click to run as administrator.
Type (without the quotes): netsh int isa set state disabled
Leave the command prompt open.
Now open up device manager, go to view and select “show hidden devices”.
In the device list, go to network adapters and disable the “Toredo tunneling interface” and the “6to4 adapter”.
To remove the large amount of tunnel adapters you can use this batch file, thanks to: Ryan Victory.
Remove tunnel adapters Batch file download link
You extract the content and run as administrator (right click) the 6to4remover.bat file from the folder that corresponds to you OS architecture (32 or 64 bit).
If you get a popup asking to accept license terms for devcon.exe, accept it. Maybe you then have to run as administrator it again to start. When it’s started it will remove all excess adapters.

Removing tunnels

Removing tunnels

After these actions are complete reboot your system. It should be back to normal.

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