This controls whether the unit blindly forwards every multicast packet arriving from the satellite link out to the Ethernet side, regardless of actual IGMP group membership on the LAN. Enabling this on a bandwidth-constrained satellite backhaul risks flooding the customer LAN with unwanted multicast streams nobody actually requested, which is exactly why enabling IGMP-aware forwarding instead is usually the preferred alternative to this blunt forward-everything setting. For example, leaving this enabled alongside several unused multicast feeds arriving over the satellite link would waste scarce LAN bandwidth on streams no local device is even watching.