Chapter 12 Load Balancing for FortiOS 5.0 : Configuring load balancing : IP, TCP, and UDP load balancing
  
IP, TCP, and UDP load balancing
You can load balance all IP, TCP or UDP sessions accepted by the security policy that includes a load balancing virtual server with the type set to IP, TCP, or UDP. Traffic with destination IP and port that matches the virtual server IP and port is load balanced. For these protocol-level load balancing virtual servers you can select a load balance method and add real servers and health checking. However, you can’t configure persistence, HTTP multiplexing and SSL offloading.