The arp learning multicast enable command globally enables a device to learn multicast MAC addresses and generate dynamic Address Resolution Protocol (ARP) entries.
The undo arp learning multicast enable command globally disables a device from learning multicast MAC addresses and generate dynamic ARP entries.
By default, a device is globally disabled from learning multicast MAC addresses.
Usage Scenario
A MAC address corresponding to an IP address may be a multicast MAC address. In this case, a network administrator has to configure a static ARP entry. A device can generate dynamic ARP entries if enabled to learn multicast MAC addresses. This way reduces a network administrator's workload of configuring static ARP entries and reduces network operation and maintenance costs.
Configuration Impact
After a device is enabled to learn multicast MAC addresses, the device may be attacked by ARP attack packets carrying multicast MAC addresses as source MAC addresses.
Precautions
You can run the arp learning multicast enable or arp learning multicast disable command to control the range for learning multicast MAC addresses in a refined manner.