The MAC address consistency check function for ARP packets prevents attacks from bogus ARP packets in which the source and destination MAC addresses are different from those in the Ethernet frame header. This function is usually configured on gateways.
This function enables the gateway to check the MAC address consistency in an ARP packet before ARP learning. If the source and destination MAC addresses in an ARP packet are different from those in the Ethernet frame header, the device discards the packet as an attack. If the source and destination MAC addresses in an ARP packet are the same as those in the Ethernet frame header, the device performs ARP learning.