Final answer:
An OS X device uses the Address Resolution Protocol (ARP) to find the MAC address for a destination IP address. ARP assists in translating IP addresses into the physical MAC addresses necessary for local network communication. The process involves sending ARP requests and receiving ARP replies to establish IP-MAC mappings in the ARP cache.
Step-by-step explanation:
An OS X device uses the Address Resolution Protocol (ARP) to determine the MAC address corresponding to a destination IP address. When an OS X device sends information over a network, it must translate the IP address of the destination into a MAC address, which represents the physical address of a network interface. ARP is a protocol used for mapping an IP address to a physical machine address that is recognized in the local network. For instance, when an OS X device wants to communicate with another device on the same local network, it broadcasts an ARP request with the known IP address, asking 'Who has this IP address? Please send me your MAC address.'
If a device with the specified IP address is present on the network, it responds with an ARP reply, which includes its MAC address. The requesting device then updates its ARP cache with this information, creating a record that associates the IP address with the corresponding MAC address, thereby enabling communication over the network. If no response is received, the device may continue to try again or report a communication problem to the user.
It's important to note that ARP is used for IPv4. In contrast, Neighbor Discovery Protocol (NDP) is used in IPv6 networks to perform the same function as ARP in mapping IP addresses to MAC addresses.