Windows Server 2008 Remote Access and Network Access Protection
VPN servers running Windows Server 2008 and Windows Server 2008 R2 support the PPTP, L2TP/IPsec, and SSTP protocols. SSTP can be used only by computers running Windows Vista or Windows 7.
VPN servers running Windows Server 2008 R2 support IKEv2 VPNs. VPNs using IKEv2 support automatic reconnection, but they can be used only by computers running Windows 7.
DirectAccess is an always-on IPv6 remote access solution. It requires a computer running Windows Server 2008 R2 and supports only clients running Windows 7 Enterprise and Ultimate editions.
You can configure a computer running Windows Server 2008 or Windows Server 2008 R2 to function as a RADIUS server, RADIUS proxy, or RADIUS client.
The four methods of local NAP enforcement are IPsec, DHCP, VPN, and 802.1X enforcement. You can also configure NAP enforcement for RD Gateway and DirectAccess.