What is a MAC table?

• A. Routing table for IP networks.
• B. Firewall rule set.
• C. Switch table mapping MAC addresses to ports for L2 forwarding.
• D. ARP cache on a host.

Answer: (C)

A MAC table is the switch’s memory that maps each device’s MAC address to the specific port on which that device can be reached. The switch learns these mappings by watching the source MAC address of frames as they arrive on each port, then stores the association. With this knowledge, the switch can forward frames only to the port where the destination device is connected, instead of broadcasting to all ports. If it doesn’t know where to send a frame yet, it floods to all ports except the one it came from. Entries aging over time keeps the table current as devices move. This is a data‑link layer function used to efficiently forward traffic within a local network.

It’s not a routing table for IP networks, which routers use to forward based on IP addresses. It’s not a firewall rule set, which controls access with security policies. It’s not an ARP cache on a host, which maps IP addresses to MAC addresses on a single host rather than across a switch’s ports.