This policy setting allows you to configure Intra-Site Automatic Tunnel Addressing Protocol (ISATAP), an address-to-router and host-to-host, host-to-router and router-to-host automatic tunneling technology that is used to provide unicast IPv6 connectivity between IPv6 hosts across an IPv4 intranet. If you disable or do not configure this policy setting, the local host setting is used. If you enable this policy setting, you will be able to configure ISATAP with one of the following settings: Policy Default State: If the ISATAP router name is resolved successfully, the host will have ISATAP configured with a link-local address and an address for each prefix received from the ISATAP router through stateless address auto-configuration. If the ISATAP router name is not resolved successfully, ISATAP connectivity is not available on the host using the corresponding IPv4 address. Policy Enabled State: If the ISATAP name is resolved successfully, the host will have ISATAP configured with a link-local address and an address for each prefix received from the ISATAP router through stateless address auto-configuration. If the ISATAP name is not resolved successfully, the host will have an ISATAP interface configured with a link-local address. Policy Disabled State: No ISATAP interfaces are present on the host. Fix: (1) GPO: Computer Configuration\Administrative Templates\Network\TCPIP Settings\IPv6 Transition Technologies\ISATAP State (2) REG: HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\TCPIP\v6Transition!ISATAP_State