CompTIA Server+ (SK0-004) Practice Exam

The protocol that resolves IP addresses to MAC addresses is the Address Resolution Protocol (ARP). ARP is essential for enabling communication over a network that uses the Internet Protocol (IP) by linking the logical addressing (IP addresses) to the physical addressing (MAC addresses) necessary for data transfer within a local area network.

When a device wants to send a packet to another device on the same local network, it must know the MAC address corresponding to the destination IP address. If the sending device has the IP address but not the MAC address, it will use ARP to broadcast a request asking "Who has this IP address? Please send me your MAC address." The device that owns the IP address then responds with its MAC address, enabling the sending device to encapsulate the packet in a data frame to send it on the network.

The other protocols mentioned serve different purposes: DHCP (Dynamic Host Configuration Protocol) is used to assign IP addresses to devices in a network, DNS (Domain Name System) resolves domain names to IP addresses, and RARP (Reverse Address Resolution Protocol) resolves MAC addresses to IP addresses, which is the opposite of what ARP does.