A switch links the MAC addresses of the network machines to their IP addresses in a table

If the switch does not know the destination MAC address, it will reject the message

When the switch receives a message from a sender it does not know, it will broadcast the message to the entire network

When the switch receives a message from a sender it does not know, it will link the sender's MAC address to the port number (port where the cable is connected on which it receives the message) in its switching table