I had to fix a computer with Vista Family Premium 32 bits installed where browsing the internet was nearly impossible.
Any loading of a web page would take minutes, because of a very slow DNS resolution. After investigating for a while, I found out that buggy IPv6 implementation in Vista was the culprit. Hundreds of tunnel adapters were enabled in the network panel, causing the slowdown. Disabling IPv6 completely fixed the issue -- it's a bit like using a hammer on a screw, but I didn't want to spend too much time on this.
To fix:
- Disable the IP Helper Service (only needed for IPv6)
- Hold the Windows key and type R, enter "services.msc" (without the quotes) and press Enter
- Scroll down to the IP Helper service, right click on it and select Properties
- In the dropdown box that says "Automatic" or "Manual", set it to Disabled and then click on "Apply"
- Then click on "Stop" to stop the service from running in the current session
- Click OK to exit the dialog
- Disable IPv6 for the newtork adapters
- Hold the Windows key and type R, enter "ncpa.cpl" (without the quotes) and press Enter
- Right click on each network connection (except 6to4 and isatap) and select "Properties"
- Remove the checkmark from the box next to "Internet Protocol Version 6 (TCP/IPv6)
- Click OK to exit the dialog
- Disable IPv6 in the registry
- In regedit, go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\tcpip6\Parameters
- Create a DWORD 32 bit Value and rename it to "DisabledComponents"
- Double click it and type 255 in the value box, it will disable IPv6.
- For info the value can be the combination (logical or) of the following values:
- 1 Disable tunnel interfaces
- 2 Disable 6to4
- 4 Disable ISATAP
- 8 Disable Teredo
- 16 Disable LAN and PPP interfaces
- 32 Set preference of IPv4 over IPv6
- 255 Disable IPv6 completely
- Remove all the 6to4mp and isatap adapters
- Download DevCon. It is a command line Device Manager that is useful for removing many devices at once.
- Then run
devcon remove *6to4mp devcon remove *isatap
Sources: Automating "6to4" Adapter Removal in Windows Too many Tunnel adapters