The difference between a hub and a switch

With a hub, every port receives all network traffic. When a hub receives 
a packet, it has no clue where the recipient is plugged. So it simply rebroadcasts 
the packet to all hosts plugged into the hub. The recipient "knows" its own 
IP address and responds to the packet, while all other devices on the network 
segment ignore it.

A switch, on the other hand, is smarter. A switch actually pays attention to 
where each device is plugged. When a switch receives a packet, it knows exactly 
where the intended recipient is and sends the packet to only that device. This 
security feature prevents hackers from intercepting all your network's traffic 
using a packet sniffer.

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