Updated: September 17, 2010
Applies To: Windows Server 2008 R2
DirectAccess requires the use of IPv6 so that DirectAccess clients have globally routable addresses. For organizations that are already using a native IPv6 infrastructure, DirectAccess seamlessly extends the existing infrastructure to DirectAccess client computers, and those client computers can still access Internet resources using IPv4.
For organizations that have not yet begun deploying IPv6, DirectAccess provides a straightforward way to begin IPv6 deployment without requiring an infrastructure upgrade. You can use the 6to4 and Teredo IPv6 transition technologies for connectivity across the IPv4 Internet and either NAT64 or ISATAP for connectivity across your IPv4-only intranet..
A NAT64 device translates IPv6 and IPv4 traffic so that DirectAccess client computers can access resources on your intranet that do not yet support IPv6. DirectAccess with UAG includes a built-in NAT64.
You can also use the ISATAP IPv6 transition technology so that DirectAccess clients can access IPv6-capable resources across your IPv4-only intranet.