Open control panel>network and sharing centre>setup a new network connection
Select use my Internet connection (VPN)
Type IP Address of VPN server and VPN dialler name
Type user name and password, domain optional
skip connection at this time.
Network and sharing centre>connect to a network>dial up and VPN> right click>property
Click on advanced settings>use certificate for authentication
Click on connect.
Keywords: L2TP VPN, AD CS, VPN dialler.