Enable? Disable? but what?
WAN1 <-> LAN traffic
WAN2 <-> LAN traffic
WAN1 <-> WAN2 traffic?
Say, it is set DISABLED, what is / isn't blocked?
How clear or vague is ONLINE HELP? It reads:
Multicast Pass Through
IP Multicasting occurs when a single data transmission is sent to multiple recipients at the same time. Using this feature, the Router allows IP multicast packets to be forwarded to the appropriate computers.