Which protocol resolves IP addresses to MAC addresses on a local network?

Which protocol resolves IP addresses to MAC addresses on a local network?

• A. ARP
• B. DNS
• C. DHCP
• D. ICMP

Answer: (A)

On a local network, the protocol that translates an IP address into the MAC address of the device on the same link is ARP, the Address Resolution Protocol. When a host wants to send a frame to another device on the LAN, it needs the destination’s MAC address. It first checks its ARP cache; if the MAC isn’t known, it broadcasts an ARP request asking, in effect, “Who has this IP? Tell me your MAC.” The device with that IP replies with its MAC, and the requester caches this mapping for future use. With the MAC obtained, the Ethernet frame can be addressed and delivered on the local network. DNS, DHCP, and ICMP serve different roles: DNS resolves domain names to IP addresses, DHCP assigns IP configuration to devices, and ICMP handles control messages and diagnostics (like ping). ARP is specific to resolving IP to MAC on the local network, enabling devices on the same broadcast domain to communicate at the data-link layer. In IPv6, a similar function is performed by the Neighbor Discovery Protocol.

On a local network, the protocol that translates an IP address into the MAC address of the device on the same link is ARP, the Address Resolution Protocol. When a host wants to send a frame to another device on the LAN, it needs the destination’s MAC address. It first checks its ARP cache; if the MAC isn’t known, it broadcasts an ARP request asking, in effect, “Who has this IP? Tell me your MAC.” The device with that IP replies with its MAC, and the requester caches this mapping for future use. With the MAC obtained, the Ethernet frame can be addressed and delivered on the local network.

DNS, DHCP, and ICMP serve different roles: DNS resolves domain names to IP addresses, DHCP assigns IP configuration to devices, and ICMP handles control messages and diagnostics (like ping). ARP is specific to resolving IP to MAC on the local network, enabling devices on the same broadcast domain to communicate at the data-link layer. In IPv6, a similar function is performed by the Neighbor Discovery Protocol.