Dynamic ARP Inspection
ARP (Address Resolution Protocol) it’s a communication protocol. Networking devices are
used for discovering MAC (media access control) addresses, associating with an IPv4
address (internet layer address), and mapping the MAC addresses to IPv4 addresses, this
mapping is done dynamically and stored in the ARP cache. ARP works between layer 2 and
layer 3 of the OSI because the MAC address exists on the data link layer and the IP address
exists on the network layer. In other words, Address Resolution Protocol (ARP) is a Layer 2
protocol that maps an IP address (Layer 3) to a MAC address (Layer 2).