Which mapping does an ARP table store?

Which mapping does an ARP table store?

• A. MAC addresses to switch ports
• B. IP addresses to MAC addresses
• C. IP addresses to hostnames
• D. MAC addresses to VLAN IDs

Answer: (B)

ARP maps IP addresses to MAC addresses on the local network. This mapping is stored in the ARP table so a device can place the correct hardware address in the Ethernet frame header when sending to a specific IP. When a host wants to reach another host on the same LAN, it looks up the destination IP in its ARP cache; if the entry isn’t there, it broadcasts an ARP request and the reply provides the destination’s MAC. The device then caches the IP-to-MAC pair for future use, allowing efficient delivery without repeated ARP requests. This is different from a switch’s CAM table, which maps MAC addresses to switch ports, or from DNS, which maps domain names to IPs, or from VLAN-related mappings.

ARP maps IP addresses to MAC addresses on the local network. This mapping is stored in the ARP table so a device can place the correct hardware address in the Ethernet frame header when sending to a specific IP. When a host wants to reach another host on the same LAN, it looks up the destination IP in its ARP cache; if the entry isn’t there, it broadcasts an ARP request and the reply provides the destination’s MAC. The device then caches the IP-to-MAC pair for future use, allowing efficient delivery without repeated ARP requests. This is different from a switch’s CAM table, which maps MAC addresses to switch ports, or from DNS, which maps domain names to IPs, or from VLAN-related mappings.