Chapter 11 IPsec VPN for FortiOS 5.0 : Dynamic DNS configuration : Configure the fixed-address VPN peer
  
Configure the fixed-address VPN peer
The fixed-address VPN peer, branch_1, needs to retrieve the IP address from the dynamic DNS service to initiate communication with the dynamically-addressed peer, branch_2. It also depends on the peer ID (local ID) to initiate the VPN tunnel with branch_2.
Figure 263: Configure branch_1, the fixed address side
Configuring the fixed-address VPN peer includes:
Configuring branch_1 VPN tunnel settings
Configuring branch_1 security policies