ARP Inspection is a security feature used in network infrastructure to protect against Address Resolution Protocol (ARP) spoofing and poisoning attacks. ARP normally translates IP addresses into MAC addresses for device communication on local networks, but attackers can exploit this by sending forged ARP messages to intercept or manipulate network traffic. ARP Inspection works by validating all ARP packets against a trusted database, typically derived from DHCP snooping binding tables, and dropping any packets that contain unauthorized or mismatched IP-to-MAC address bindings.

When enabled on network switches, ARP Inspection examines incoming ARP requests and replies, verifying that the sender's IP and MAC addresses match legitimate entries. Packets that fail this validation are discarded, and security alerts are generated. This mechanism effectively prevents man-in-the-middle attacks, session hijacking, and denial-of-service attempts that rely on ARP manipulation, making it an essential component of a comprehensive defense-in-depth cybersecurity strategy for protecting network integrity and data confidentiality.