Which protocol maps an IP address to a MAC address in a local area network?

Which protocol maps an IP address to a MAC address in a local area network?

• A. ARP
• B. DNS
• C. DHCP
• D. ICMP

Answer: (A)

When a device on a local network needs to send data to another device, it must know the recipient’s hardware address (MAC address) to deliver the frame at the data-link layer. ARP, the Address Resolution Protocol, provides that mapping from an IP address to a MAC address. If the sender doesn’t know the MAC yet, it broadcasts an ARP request on the local network asking which device has that IP, and the matching device replies with its MAC address, which the sender caches for future use. DNS deals with translating domain names to IP addresses, not MACs. DHCP assigns IP addresses and configuration to devices. ICMP is used for control messages and diagnostics like reachability (pings). So ARP is the protocol that maps an IP address to a MAC address on a LAN, enabling actual data delivery within the local network.

When a device on a local network needs to send data to another device, it must know the recipient’s hardware address (MAC address) to deliver the frame at the data-link layer. ARP, the Address Resolution Protocol, provides that mapping from an IP address to a MAC address. If the sender doesn’t know the MAC yet, it broadcasts an ARP request on the local network asking which device has that IP, and the matching device replies with its MAC address, which the sender caches for future use. DNS deals with translating domain names to IP addresses, not MACs. DHCP assigns IP addresses and configuration to devices. ICMP is used for control messages and diagnostics like reachability (pings). So ARP is the protocol that maps an IP address to a MAC address on a LAN, enabling actual data delivery within the local network.