IP Locking is an EOS feature configured on an Ethernet Layer 2 port or on a VLAN. When enabled, it ensures that a configured port or all member ports of a configured VLAN will only permit IP and ARP packets with IP source addresses that have been authorized. IP Locking prevents another host on a different IP Locking enabled interface from claiming ownership of an IP address through either IP or ARP spoofing. Additionally, IP Locking prevents hosts from masquerading as a DHCP server by blocking DHCP (server-to-client) packets.