The RUCKUS ICX router must be configured to have Gratuitous Address Resolution Protocol (ARP) disabled on all external interfaces.

A gratuitous ARP is an ARP broadcast in which the source and destination MAC addresses are the same. It is used to inform the network about a host IP address. A spoofed gratuitous ARP message can cause network mapping information to be stored incorrectly, causing network malfunction.

The RUCKUS ICX disables gratuitous ARP by default. Review the configuration to verify the command below does not appear.

ip arp learn-gratuitous-arp

If the above command is present in the configuration, this is a finding.

Disable learning of gratuitous ARPs:

ICX(config)#no ip arp learn-gratuitous-arp