Which of the following is kept in a computer's Address Resolution Protocol (ARP) cache?

The Address Resolution Protocol (ARP) cache is specifically designed to map IP addresses to their corresponding Media Access Control (MAC) addresses. When a device wants to communicate with another device on a local network, it needs to know the MAC address associated with the intended recipient's IP address. The ARP cache temporarily stores this mapping to facilitate faster communication and reduce the need for repeated ARP requests.

The correct choice involves the pairing of IP addresses with their associated MAC addresses, which is precisely what the ARP cache retains. This allows devices to efficiently route frames through the network at the data link layer, using the MAC address to deliver packets accurately.

The other options do not correctly reflect the purpose of the ARP cache:

• The IP address and DNS name are related but typically handled by the Domain Name System (DNS), not ARP.

• MAC addresses and hostnames involve higher-level resolutions that ARP does not address directly.

• The subnet mask along with the IP address is essential for network configuration but is not part of the ARP cache’s function.

Thus, understanding the role of the ARP cache in networking clarifies why the pairing of IP addresses with MAC addresses is fundamental to its purpose.