firewall defend icmp-flood interface { interface-type interface-number | all

} threshold rate action { alert | drop | reset }

This command configures a firewall to defend against an ICMP flood attack on a specific interface or on all interfaces. The threshold rate specifies the maximum number of ICMP packets per second allowed on the interface. If the threshold is exceeded, the specified action is taken, which can be to alert the administrator, drop the packets, or reset the connection. This helps to prevent the network from being overwhelmed by excessive ICMP traffic, which can be caused by a denial-of-service (DoS) attack or other malicious activity.