Configuring Rate Limiting on ARP Miss Messages Globally, in a VLAN, or on an Interface
Context
If a user host sends a large number of IP packets with unresolvable destination IP addresses to a network device (the device has a route to the destination IP address of a packet but has no ARP entry matching the next hop of the route), the device generates a large number of ARP Miss messages. IP packets triggering ARP Miss messages are sent to the device for processing. The device generates a large number of temporary ARP entries and sends many ARP Request packets to the network, consuming a large number of CPU and bandwidth resources.
To avoid the preceding problems, it is recommended that you configure rate limit on ARP Miss messages on the gateway.
Limiting the rate of ARP Miss messages globally: limits the number of ARP Miss messages processed on the entire device.
Limiting the rate of ARP Miss messages in a VLAN: limits the number of ARP Miss messages processed on all interfaces in a VLAN. The configuration in a VLAN does not affect IP packet forwarding on interfaces in other VLANs.
Limiting the rate of ARP Miss messages on an interface: limits the number of ARP Miss messages processed on an interface. The configuration on an interface does not affect IP packet forwarding on other interfaces.
If rate limit on ARP Miss messages is configured in the system view, VLAN view, and interface view, the device uses the configurations in the interface view, VLAN view, and system view in order.
Procedure
- Run system-view
The system view is displayed.
- (Optional) Run the interface interface-type interface-number command to enter the Layer 2 interface view, and then the undo portswitch command to enter the Layer 3 interface view. Alternatively,
run the vlan vlan-id command to enter the VLAN view.
This step is not required when you configure ARP Miss rate limit in the system view.
- Run arp miss anti-attack rate-limit limit
The maximum rate of ARP Miss messages is set.
By default, the global rate limit on ARP Miss messages is 3000 packets per second, and the rate limit for ARP Miss messages in a VLAN or interface is disabled.
- Run commit
The configuration is committed.
