> Dumb switches will blast packets to all interfaces that are connected Multicast and broadcast sure, but dumb switches will still keep mac-address>port mappin

> Dumb switches will blast packets to all interfaces that are connected Multicast and broadcast sure, but dumb switches will still keep mac-address>port mapping. If the router sends to 52:54:00:ad:ra:a7, the dumb switch will remember that's on port 7 (having seen traffic from it recently - if only an arp reply) and only send the packet to port 7. Hubs (remember them!) will blast every packet to every port.