Chapter 1 What’s New for FortiOS 5.2.1 : Top Features : Internet Key Exchange (IKE)
  
Internet Key Exchange (IKE)
Several new options have been added for how IKE is supported on a FortiGate:
Multiple interfaces
Mode-configuration
Certificates groups
Authentication methods
Inheriting groups from the security policy
Assigning client IP addresses using the DHCP proxy
Transform matching
Cookie notification
Message ID sync for High Availability
For more information, see “Internet Key Exchange (IKE)”.