Hack the Route Start free Open app Interception
DHCP snooping and ARP inspection
Switch features that learn which device holds which address, and drop answers that do not match.
DHCP snooping allows DHCP offers only from trusted ports and records each lease; dynamic ARP inspection drops ARP replies that contradict those records. Together they stop devices on a port from claiming addresses that are not theirs. The leases the switch saw form its binding table (MAC, IP, port, lease time); ports toward the real DHCP server, other switches, and devices with addresses set by hand are made trusted, since they have no lease to check.