Why enable IPv6?
there are various reasons for this. One that might not be so obvious is because there are more and more applications that need IPv6 and rely on the fact that IPv6 is enabled by default (on Windows Vista or Windows Server 2008)
Turning IPv6 off brings you on untested grounds resulting in components that no longer function.
Support has solved a lot of problems that could have been avoided by keeping IPv6 turned on.
For more information on this please read Support for IPv6 in Windows Server 2008 R2 and Windows 7
So how to do this:
from the cmd line in case someone has unchecked IPv6 mistakenly.
This is especially useful when you have no GUI – e.g. on Server Core / Hyper-V Server or when you need to check network connection properties | network settings like below for an unattended installation.
Using WMI or other built-in tools seem to be a dead end. Doing so in the registry is one way.
Here is an unsupported tool that you could use at your own risk:
NVSPBind is the tool that lets you enable protocols (e.g. IPv6) on a network adapter using the command line:
nvspbind.exe /e "Local Area Connection" ms_tcpip6
ms_netbios NetBIOS Interface ms_server File and Printer Sharing for Microsoft Networks ms_pacer QoS Packet Scheduler ms_ndiscap NDIS Capture LightWeight Filter ms_wfplwf WFP Lightweight Filter ms_msclient Client for Microsoft Networks ms_lltdio Link-Layer Topology Discovery Mapper I/O Driver ms_rspndr Link-Layer Topology Discovery Responder ms_ndisuio NDIS Usermode I/O Protocol ms_pppoe Point to Point Protocol Over Ethernet ms_tcpip6 Internet Protocol Version 6 (TCP/IPv6) ms_netbt WINS Client(TCP/IP) Protocol ms_smb Microsoft NetbiosSmb ms_tcpip Internet Protocol Version 4 (TCP/IPv4) vms_pp Microsoft Virtual Network Switch Protocol
Download NVSBind from MSDN.