Cisco Dynamic ARP Inspection!!! | IPCisco.com . Dynamic ARP Inspection (DAI) is a network security feature that prevents Address Resolution Protocol (ARP) spoofing and man-in-the-middle attacks by intercepting ARP packets, validating their IP-to-MAC address bindings against a trusted DHCP snooping binding database, and dropping invalid packets that do not match the valid entries. To function, DAI requires DHCP snooping to be enabled on the switch, which populates the trusted database with valid