What is ARP used for?

• A. Mapping IP addresses to MAC addresses.
• B. Translating domain names into IP addresses.
• C. Encrypting payloads for VPNs.
• D. Routing IP packets to destinations.

Answer: (A)

ARP is used to map IP addresses to MAC addresses on a local network. When a host needs to deliver an IPv4 packet to another device on the same Ethernet network, it must know the destination’s MAC address to place in the frame header. If that MAC is not known, the sender broadcasts an ARP request asking who has the specific IP, and the owner replies with its MAC. The requesting host then caches this mapping for future communication. This function is distinct from DNS, which translates domain names to IPs, from VPN encryption, and from routing, which moves packets between networks. ARP specifically bridges IP addressing with the hardware addresses used on the local link.