Chapter 11 IPsec VPN for FortiOS 5.0 : Dynamic DNS configuration : Configure the dynamically-addressed VPN peer
  
Configure the dynamically-addressed VPN peer
It is assumed that this FortiGate unit (branch_2) has already had its public facing interface, for example the wan1, configured with the proper dynamic DNS configuration.
Figure 262: Configure branch_2, the dynamic address side
Configuring the dynamically-addressed VPN peer includes:
Configuring branch_2 VPN tunnel settings
Configuring branch_2 security policies