Which statement about ARP in IPv4 networks is true?

• A. ARP broadcasts requests to discover MAC addresses only when the specific device is on the same LAN
• B. ARP is used to manage DNS mappings for hosts
• C. ARP resolves IPv4 addresses to MAC addresses on the local network
• D. ARP is used to route packets between subnets

Answer: (C)

In IPv4, ARP’s job is to map an IP address to a hardware (MAC) address on the local network. A host that wants to send an IP packet to another host on the same subnet first checks its ARP cache. If it doesn’t know the MAC, it broadcasts an ARP request on the local LAN asking who has that IPv4 address. The device that owns that IP replies with its MAC, and the requester can then send the Ethernet frame addressed to that MAC. This process happens only within the local network segment; routers handle cross-subnet traffic and learn the MAC of the next-hop on each local network as needed. DNS mappings and name resolution are separate from ARP, and ARP isn’t used to route packets between subnets. Therefore, ARP’s primary function is resolving IPv4 addresses to MAC addresses on the local network.