Your network contains an Active Directory domain named contoso.com. The network is configured
to use ISATAP. You have a server named Server1 that runs Windows Server 2008 R2. On Server1, you
discover that a tunnel adapter named isatap.contoso.com has a Media State of “Media
disconnected”. You confirm that Server1 has a valid network connection and can query the DNS
server. You need to ensure that the isatap.contoso.com tunnel adapter has an IPv6 address. What
should you do?

A.
Start the IP Helper service.

B.
Start the IPsec Policy Agent service.

C.
Add a new rule to Windows Firewall.

D.
Add an entry for ISATAP to the Hosts file.

Explanation:
The IP Helper service service must be running for IPv6 transition technologies such as ISATAP,
Teredo, and 6to4 to function on the computer. This service provides automatic IPv6 connectivity
over an IPv4 network, and if the service is stopped, the computer will have only IPv6 connectivity if it
is connected to a native IPv6 network. Therefore, if your network is not native IPv6, disabling this
service on Windows Server 2008 computers effectively disables IPv6 on them.