As part of troubleshooting the Cisco VPN with my Vista system, I’ve been asked to “turn off” IPv6, just in case. I decided to take the comprehensive approach, as described in the IPv6 for Microsoft Windows FAQ, and use the registry:
Add the following registry value (DWORD type) set to 0xFFFFFFFF:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters\DisabledComponents
This method disables IPv6 on all your LAN interfaces, connections, and tunnel interfaces but does not disable the IPv6 loopback interface. You must restart the computer for this registry value to take effect.
Beware that there are Windows features, most prominently in my experience Windows Meeting Space, which require IPv6 to function. I think IPv6 is pretty cool, though, so I’ll turn it back on and keep thinking about how to integrate it into our infrastructure.
Resources:
- IPv6 at WikiPedia
- EDUCAUSE Live! “IPv4 Depletion and Migration to IPv6” (see the event archives)
- Microsoft’s IPv6 Tech Center
Update:
It turns out that disabling IPv6 system-wide or just on the adapters involved in the VPN connection (Wireless and VPNVirtual adapters, in my case) has resolved the connectivity issues I have experienced most recently with the Cisco VPN. As someone who uses the IPv6-dependent applications, I find this less than optimal.
More IPv6 resources (added as I find them…)
- IPv6 presentations on Google Tech Talks channel
- Technet On-Demand WebCast: Introduction to Internet Protocol Version 6
- Technet On-Demand WebCast: IPv6 Transition Technologies
