Chapter 11 IPsec VPN for FortiOS 5.0 : L2TP and IPsec (Microsoft VPN) : Configuring the FortiGate unit
  
Configuring the FortiGate unit
To configure the FortiGate unit, you need to:
configure LT2P users and firewall user group;
configure the L2TP VPN, including the IP address range it assigns to clients;
configure an IPsec VPN with encryption and authentication settings that match the Microsoft VPN client;
configure security policies.