reset arp

Function

The reset arp command clears Address Resolution Protocol (ARP) entries.

Format

reset arp { dynamic [ ip ip-address [ vpn-instance vpn-instance-name ] ] | interface interface-type interface-number [ ip ip-address ] | packet statistics | static }

Parameters

Parameter	Description	Value
dynamic	Clears the dynamic ARP entries.	-
interface interface-type interface-number	Clears the dynamic ARP entries learned on the specified interface. interface-type specifies the type of the interface. interface-number specifies the number of the interface.	-
ip ip-address	Clears the dynamic ARP entry corresponding to the specified IP address learned on the specified interface. To delete one of the several ARP entries learned on a specified interface, you can specify the IP address that the ARP entry contains in the reset arp command.	It is in dotted decimal notation.
packet statistics	Clears the statistics on ARP packets.	-
static	Clears the static ARP entries. Static ARP entries cannot be restored after you clear them, so confirm the action before you use the command.	-
ip ip-address	Clears the dynamic ARP entries corresponding to the specified IP address.	This value is in dotted decimal notation.
vpn-instance vpn-instance-name	Clears the dynamic ARP entry corresponding to the specified IP address in the specified VPN. Since one IP address may be learned in different VPNs, If no VPN instance is specified, the dynamic ARP entries corresponding to the specified IP address in the public network instance will be cleared. If one VPN instance is specified, the dynamic ARP entry corresponding to the specified IP address in the specified VPN instance is cleared.	The value is a string of 1 to 31 case-sensitive characters and cannot contain a space.

Views

User view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

If an unauthorized user sends a large number of ARP packets to a device, the device learns a large number of ARP entries in a short period of time, causing the buffer to overflow. As a result, users may fail to access the network. To solve the problem, you can run the reset arp command to delete invalid ARP entries and create new ARP entries to ensure that users can access the network.

Prerequisites

Before using the reset arp command, ensure that the corresponding ARP entries exist.
Before using the reset arp command in the specified VPN instance, ensure the specified VPN instance exists.

Configuration Impact

After an ARP entry is cleared, the mapping between the IP address and the MAC address is cleared. As a result, users may fail to assess the network and services may be interrupted.

Precautions

ARP entries are cleared at an interval of at least 20s.

Example

# Clear the static entry in the ARP mapping table of the main control board.

<sysname> reset arp static

# Clear the dynamic entry in the ARP mapping table on GigabitEthernet 0/0/1.

<sysname> reset arp interface GigabitEthernet 0/0/1