Chapter 7 Firewall for FortiOS 5.0 : Multicast forwarding : Multicast forwarding and FortiGate units : Multicast forwarding and RIPv2
  
Multicast forwarding and RIPv2
RIPv2 uses multicast to share routing table information. If your FortiGate unit is installed on a network that includes RIPv2 routers, you must configure the FortiGate unit to forward multicast packets so that RIPv2 devices can share routing data through the FortiGate unit. No special FortiGate configuration is required to share RIPv2 data, you can simply use the information in the following sections to configure the FortiGate unit to forward multicast packets.
 
RIPv1 uses broadcasting to share routing table information. To allow RIPv1 packets through a FortiGate unit you can add standard security policies. Security policies to accept RIPv1 packets can use the ANY predefined firewall service or the RIP predefined firewall service.
Figure 176: Example multicast network including a FortiGate unit that forwards multicast packets