Chapter 11 IPsec VPN for FortiOS 5.0 : Gateway-to-gateway configurations
  
Gateway-to-gateway configurations
This section explains how to set up a basic gateway-to-gateway (site-to-site) IPsec VPN.
The following topics are included in this section:
• Configuration overview
• General configuration steps
• Configuring the two VPN peers
• How to work with overlapping subnets
• Testing
Video: Creating a VPN between a branch office and headquarters