CREST Practitioner Security Analyst (CPSA) Practice 2026 - Free CPSA Practice Questions and Study Guide

ARP stands for Address Resolution Protocol. It is a critical protocol in networking that is used to map an Internet Protocol (IP) address to a physical machine address that is recognized in the local network. This allows devices to communicate over a TCP/IP network, as it translates the logical addresses (IP addresses) into physical addresses (MAC addresses) that network hardware, like switches and routers, can use to route packets appropriately.

When a device wants to communicate with another device on the same local area network (LAN), it needs to know the MAC address corresponding to the IP address of the target device. ARP provides this capability by broadcasting a request onto the network asking, "Who has IP address X.X.X.X?" The device that recognizes its own IP address responds with its MAC address. This mechanism is essential for the functioning of the Ethernet and similar networking technologies, facilitating efficient communication between devices.