Which protocol is used to find a MAC address from an IP address?

Concept

Address resolution links a network-layer protocol address to the link-layer hardware address needed to deliver a frame on a local network.

The direction of the mapping matters: a protocol-address-to-hardware-address lookup is different from a hardware-address-to-protocol-address lookup.

Application

1. A sender knows the destination IPv4 address but needs a destination MAC address for the local Ethernet frame.

2. ARP broadcasts a request for the device that owns that IPv4 address.

3. The matching device replies with its MAC address, which the sender uses in the frame.

Cross-check and contrast

• RARP begins with a known MAC address and obtains an IP address.

• ICMP carries IP control and error messages, including ping-related messages.

• SMTP transfers email at the application layer.

Therefore, the required protocol is ARP (Address Resolution Protocol).