Dynamic ARP entry check disables a device from supporting dynamic ARP entries with multicast MAC addresses. The device cannot learn dynamic ARP entries containing multicast MAC addresses. You cannot manually add static ARP entries that contain multicast MAC addresses.

When dynamic ARP entry check is disabled, ARP entries containing multicast MAC addresses are supported. The device can learn dynamic ARP entries containing multicast MAC addresses obtained from the ARP packets sourced from a unicast MAC address. You can also manually add static ARP entries containing multicast MAC addresses.

Examples

# Enable dynamic ARP entry check.

<Sysname> system-view

[Sysname] arp check enable

arp check log enable

Use arp check log enable to enable the ARP logging feature.

Use undo arp check log enable to disable the ARP logging feature.

Syntax

arp check log enable

undo arp check log enable

Default

ARP logging is disabled.

Views

System view

Predefined user roles

network-admin

Usage guidelines

This feature enables a device to log ARP events when ARP cannot resolve IP addresses correctly. The log information helps administrators locate and solve problems. The device can log the following ARP events:

· On a proxy ARP-disabled interface, the target IP address of a received ARP packet is not the IP address of the receiving interface.

· The sender IP address of a received ARP reply conflicts with the IP address of the receiving interface.

The device sends ARP log messages to the information center. You can use the info-center source command to specify the log output rules for the information center. For more information about information center, see System Management Configuration Guide.

The device can generate a large number of ARP logs. To conserve system resources, enable ARP logging only when you are auditing or troubleshooting ARP events.

Examples

# Enable ARP logging.

<Sysname> system-view

[Sysname] arp check log enable

arp ip-unnumbered learning enable

Use arp ip-unnumbered learning enable to enable an IP unnumbered interface to learn ARP entries for different subnets.

Use undo arp ip-unnumbered learning enable to disable an IP unnumbered interface from learning ARP entries for different subnets.

Syntax

arp ip-unnumbered learning enable

undo arp ip-unnumbered learning enable

Default

An IP unnumbered interface cannot learn ARP entries for different subnets.

Views

Interface view

Predefined user roles

network-admin

Usage guidelines

An IP unnumbered interface cannot learn the ARP entry of the peer device if the unnumbered interface and the peer device are on different subnets. To ensure communication between them, you can enable this feature on the IP unnumbered interface.

This feature takes effect only on an interface configured with the ip address unnumbered command. This interface is an unnumbered interface and borrows the IP address from another interface.

If an IP unnumbered interface is disabled from learning ARP entries for different subnets, existing ARP entries learned for different subnets are deleted after they age out.

Examples

# Configure GigabitEthernet 1/0/1 to borrow the IP address of GigabitEthernet 1/0/2, and enable GigabitEthernet 1/0/1 to learn ARP entries for different subnets.

<Sysname> system-view

[Sysname] interface gigabitethernet 1/0/1

[Sysname-GigabitEthernet1/0/1] ip address unnumbered interface gigabitethernet 1/0/2

[Sysname-GigabitEthernet1/0/1] arp ip-unnumbered learning enable

Related commands

ip address unnumbered

arp mac-interface-consistency check enable

Use arp mac-interface-consistency check enable to enable interface consistency check between ARP and MAC address entries.

Use undo arp mac-interface-consistency check enable to disable interface consistency check between ARP and MAC address entries.

Syntax

arp mac-interface-consistency check enable

undo arp mac-interface-consistency check enable

Default

Interface consistency check between ARP and MAC address entries is disabled.

Views

System view

Predefined user roles

network-admin

Usage guidelines

In an unstable network, the receiving interface for packets from a user might change. The interface in the MAC address entry can be updated immediately while the interface in the ARP entry cannot. In this case, the packets matching the ARP entry will be sent out of an incorrect interface. To solve this problem, you can use this feature to periodically check the interface consistency between the ARP and MAC address entry for a user. If the interfaces are not the same, ARP sends ARP requests in the VLAN of the ARP entry and updates the entry with the ARP reply receiving interface.

Use the display mac-address command to display MAC address entries.

Examples

# Enable interface consistency check between ARP and MAC address entries.

<Sysname> system-view

[Sysname] arp mac-interface-consistency check enable

Related commands

display mac-address (Network Connectivity Command Reference)

arp max-learning-num

Use arp max-learning-num to set the dynamic ARP learning limit for an interface.

Use undo arp max-learning-num to restore the default.

Syntax

arp max-learning-num max-number

undo arp max-learning-num

Default

The default value is the maximum number of the max-number argument.

Views

Layer 2 Ethernet interface view

Layer 2 aggregate interface view

VLAN interface view

Predefined user roles

network-admin

Parameters

max-number: Specifies the maximum number of dynamic ARP entries for an interface.

The following compatibility matrixes show the value ranges for the maximum number of dynamic ARP entries:

Series	Models	Product codes	Value ranges
WX3500X series	WX3510X WX3520X WX3540X	EWP-WX3510X EWP-WX3520X EWP-WX3540X	EWP-WX3510X: 0 to 15360 EWP-WX3520X: 0 to 30720 EWP-WX3540X: 0 to 61440
WCG380 series	WCG382	EWP-WCG382	0 to 16384

Series

Models

Product codes

Value ranges

WX3500X series

WX3510X

WX3520X

WX3540X

EWP-WX3510X

EWP-WX3520X

EWP-WX3540X

EWP-WX3510X: 0 to 15360

EWP-WX3520X: 0 to 30720

EWP-WX3540X: 0 to 61440

WCG380 series

WCG382

EWP-WCG382

0 to 16384

Series	Models	Product codes	Value ranges
WX3800X series	WX3820X WX3840X	EWP-WX3820X EWP-WX3840X	EWP-WX3820X: 0 to 30720 EWP-WX3840X: 0 to 61440

Series

Models

Product codes

Value ranges

WX3800X series

WX3820X

WX3840X

EWP-WX3820X

EWP-WX3840X

EWP-WX3820X: 0 to 30720

EWP-WX3840X: 0 to 61440

Usage guidelines

An interface can dynamically learn ARP entries. To prevent an interface from holding too many ARP entries, you can set the maximum number of dynamic ARP entries that the interface can learn. When the maximum number is reached, the interface stops learning ARP entries.

When the number argument is set to 0, the interface is disabled from learning dynamic ARP entries.

Examples

# Specify VLAN-interface 40 to learn a maximum of 10 dynamic ARP entries.

<Sysname> system-view

[Sysname] interface vlan-interface 40

[Sysname-Vlan-interface40] arp max-learning-num 10

# Specify GigabitEthernet 1/0/1 to learn a maximum of 10 dynamic ARP entries.

<Sysname> system-view

[Sysname] interface gigabitethernet 1/0/1

[Sysname-GigabitEthernet1/0/1] arp max-learning-num 10

# Specify Layer 2 aggregate interface Bridge-Aggregation 1 to learn a maximum of 10 dynamic ARP entries.

<Sysname> system-view

[Sysname] interface bridge-aggregation 1

[Sysname-Bridge-Aggregation1] arp max-learning-num 10

arp max-learning-number

Use arp max-learning-number to set the dynamic ARP learning limit for a device.

Use undo arp max-learning-number to restore the default.

Syntax

arp max-learning-number max-number

undo arp max-learning-number

Default

The default value is the maximum number of the max-number argument.

Views

System view

Predefined user roles

network-admin

Parameters

max-number: Specifies the maximum number of dynamic ARP entries for a device.

The following compatibility matrixes show the value ranges for the maximum number of dynamic ARP entries:

Series	Models	Product codes	Value ranges
WX3500X series	WX3510X WX3520X WX3540X	EWP-WX3510X EWP-WX3520X EWP-WX3540X	EWP-WX3510X: 0 to 15360 EWP-WX3520X: 0 to 30720 EWP-WX3540X: 0 to 61440
WCG380 series	WCG382	EWP-WCG382	0 to 16384

Series

Models

Product codes

Value ranges

WX3500X series

WX3510X

WX3520X

WX3540X

EWP-WX3510X

EWP-WX3520X

EWP-WX3540X

EWP-WX3510X: 0 to 15360

EWP-WX3520X: 0 to 30720

EWP-WX3540X: 0 to 61440

WCG380 series

WCG382

EWP-WCG382

0 to 16384

Series	Models	Product codes	Value ranges
WX3800X series	WX3820X WX3840X	EWP-WX3820X EWP-WX3840X	EWP-WX3820X: 0 to 30720 EWP-WX3840X: 0 to 61440

Series

Models

Product codes

Value ranges

WX3800X series

WX3820X

WX3840X

EWP-WX3820X

EWP-WX3840X

EWP-WX3820X: 0 to 30720

EWP-WX3840X: 0 to 61440

Usage guidelines

A device can dynamically learn ARP entries. To prevent a device from holding too many ARP entries, you can set the maximum number of dynamic ARP entries that the device can learn. When the maximum number is reached, the device stops learning ARP entries.

When the number argument is set to 0, the device is disabled from learning dynamic ARP entries.

Examples

# Configure the device to learn a maximum of 64 dynamic ARP entries.

<Sysname> system-view

[Sysname] arp max-learning-number 64

arp static

Use arp static to configure a static ARP entry.

Use undo arp to delete an ARP entry.

Syntax

arp static ip-address mac-address [ vlan-id interface-type interface-number ]

undo arp ip-address

Default

No static ARP entries exist.

Views

System view

Predefined user roles

network-admin

Parameters

ip-address: Specifies an IP address for the static ARP entry.

mac-address: Specifies a MAC address for the static ARP entry, in the format of H-H-H.

vlan-id: Specifies the ID of a VLAN to which the static ARP entry belongs. The value range is 1 to 4094.

interface-type interface-number : Specifies an interface by its type and number.

Usage guidelines

A static ARP entry is manually configured and maintained. It does not age out and cannot be overwritten by any dynamic ARP entry.

Static ARP entries can be short or long.

A resolved short static ARP entry becomes unresolved upon certain events, for example, when the resolved output interface goes down, or the corresponding VLAN or VLAN interface is deleted.

Long static ARP entries are effective or ineffective. Ineffective long static ARP entries cannot be used for packet forwarding. A long static ARP entry is ineffective when any of the following conditions exists:

· The IP address in the entry conflicts with a local IP address.

· No local interface has an IP address in the same subnet as the IP address in the ARP entry.

If you specify the vlan-id interface-type interface-number argument, follow these restrictions and guidelines:

· The interface can be an Ethernet interface or an aggregate interface.

· The VLAN and VLAN interface must already exist. The specified Ethernet interface must belong to the specified VLAN.

· The IP address of the VLAN interface and the IP address specified by the ip-address argument must be on the same network.

· A long static ARP entry in a VLAN is deleted if the VLAN or VLAN interface is deleted.

Examples

# Configure a long static ARP entry that contains IP address 202.38.10.2, MAC address 00e0-fc01-0000, and output interface GigabitEthernet 1/0/1 in VLAN 10.

<Sysname> system-view

[Sysname] arp static 202.38.10.2 00e0-fc01-0000 10 gigabitethernet 1/0/1

Related commands

display arp

reset arp

arp timer aging

Use arp timer aging to set the aging timer for dynamic ARP entries.

Use undo arp timer aging to restore the default.

Syntax

arp timer aging { aging-minutes | second aging-seconds }

undo arp timer aging

Default

The aging timer for dynamic ARP entries is 20 minutes.

Views

System view

Predefined user roles

network-admin

Parameters

aging-minutes: Specifies the aging timer in minutes. The value range for this argument is 1 to 1440.

second aging-seconds: Specifies the aging timer in seconds. The value range for the aging-seconds argument is 5 to 86400.

Usage guidelines

Each dynamic ARP entry in the ARP table has a limited lifetime, called an aging timer. The aging timer of a dynamic ARP entry is reset each time the dynamic ARP entry is updated. Dynamic ARP entries that are not updated before their aging timers expire are deleted from the ARP table.

Set the aging timer for dynamic ARP entries as needed. For example, when you configure proxy ARP, set a short aging time so that invalid dynamic ARP entries can be deleted in a timely manner.

Examples

# Set the aging timer for dynamic ARP entries to 10 minutes.

<Sysname> system-view

[Sysname] arp timer aging 10

# Set the aging timer for dynamic ARP entries to 200 seconds.

<Sysname> system-view

[Sysname] arp timer aging second 200

Related commands

display arp timer aging

arp user-ip-conflict record enable

Use arp user-ip-conflict record enable to enable recording user IP address conflicts.

Use undo arp user-ip-conflict record enable to disable recording user IP address conflicts.

Syntax

arp user-ip-conflict record enable

undo arp user-ip-conflict record enable

Default

Recording user IP address conflicts is disabled.

Views

System view

Predefined user roles

network-admin

Usage guidelines

This feature enables the device to detect and record user IP address conflicts. The device determines that a conflict occurs if an incoming ARP packet has the same sender IP address as an existing ARP entry but a different sender MAC address. The device generates a user IP address conflict record, logs the conflict, and sends the log to the information center. For information about the log destination and output rule configuration, see the information center in System Management Configuration Guide.

The device can generate a maximum of 10 user IP address conflict logs per second.

To display user IP address conflict records, use the display arp user-ip-conflict record command.

Examples

# Enable recording user IP address conflicts.

<Sysname> system-view

[Sysname] arp user-ip-conflict record enable

Related commands

display arp user-ip-conflict record

arp user-move record enable

Use user-move record enable to enable recording user port migrations.

Use undo arp user-move record enable to disable recording user port migrations.

Syntax

arp user-move record enable

undo arp user-move record enable

Default

Recording user port migrations is disabled.

Views

System view

Predefined user roles

network-admin

Usage guidelines

The device can generate a maximum of 10 user port migration logs per second.

To display user port migration records, use the display arp user-move record command.

Examples

# Enable recording user port migration.

<Sysname> system-view

[Sysname] arp user-move record enable

Related commands

display arp user-move record

display arp

Use display arp to display ARP entries.

Syntax

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

all: Displays all ARP entries.

dynamic: Displays dynamic ARP entries.

static: Displays static ARP entries.

vlan vlan-id: Specifies a VLAN by its VLAN ID. The VLAN ID is in the range of 1 to 4094.

interface interface-type interface-number: Specifies an interface by its type and number. If you do not specify an interface, this command displays ARP entries for all interfaces.

count: Displays the number of ARP entries.

verbose: Displays detailed information about ARP entries.

Usage guidelines

This command displays information about static and dynamic ARP entries, including the IP address, MAC address, VLAN ID, output interface, entry type, and aging timer.

Examples

# Display all ARP entries.

<Sysname> display arp all

Type: S-Static D-Dynamic O-Openflow R-Rule I-Invalid

IP address MAC address VLAN/VSI name Interface Aging Type

1.1.1.1 02e0-f102-0023 1 GE1/0/1 -- S

1.1.1.2 00e0-fc00-0001 12 GE1/0/2 960 D

1.1.1.3 00e0-fe50-6503 vsi1 Tunnel1 960 D

# Display detailed information about all ARP entries.

<Sysname> display arp all verbose

Type: S-Static D-Dynamic O-Openflow R-Rule I-Invalid

IP address : 1.1.1.1 MAC address : 02e0-f102-0023

Type : Static Aging : --

Interface : GE1/0/1 SVLAN/CVLAN : 1/--

VPN instance : --

Link ID : --

Service instance : --

VXLAN ID : --

VSI name : --

VSI interface : --

IP address : 1.1.1.2 MAC address : 00e0-fc00-0001

Type : Dynamic Aging : 960 seconds

Interface : GE1/0/2 SVLAN/CVLAN : 12/--

VPN instance : --

Link ID : --

Service instance : --

VXLAN ID : --

VSI name : --

VSI interface : --

IP address : 1.1.1.3 MAC address : 00e0-fe50-6503

Type : Dynamic Aging : 960 seconds

Interface : Tunnel1 SVLAN/CVLAN : 12/--

VPN instance : --

Link ID : --

Service instance : --

VXLAN ID : --

VSI name : vsi1

VSI interface : --

# Display the number of all ARP entries.

<Sysname> display arp all count

Total number of entries : 3

Table 1 Command output

Field	Description
IP address	IP address in an ARP entry.
MAC address	MAC address in an ARP entry.
VLAN/VSI name	ID of the VLAN to which an ARP entry belongs. This field displays hyphens (--) in either of the following situations: · The ARP entry is an unresolved short static ARP entry. · The output interface of the ARP entry does not belong to any SVLAN.
Interface	Output interface in an ARP entry. This field displays hyphens (--) if the ARP entry is an unresolved short static ARP entry.
Aging	Aging time for an ARP entry, in seconds. · For a static ARP entry, this field always displays hyphens (--). The static ARP entry never ages out unless you delete it manually. · For a dynamic ARP entry, this field displays hyphens (--) if the aging time is unknown.
Type	ARP entry type: · D—Dynamic. · S—Static. · O—OpenFlow. · R—Rule. · I—Invalid.
SVLAN/CVLAN	ID of the SVLAN or CVLAN to which the ARP entry belongs. This field displays hyphens (--) in either of the following situations: · The ARP entry is an unresolved short static ARP entry. · The output interface of the ARP entry does not belong to any SVLAN or CVLAN.
VPN instance	This field is not supported in the current software version. Name of VPN instance. This field displays hyphens (--) if no VPN instance is configured for the ARP entry.
Link ID	This field is not supported in the current software version. Link ID in an ARP entry. This field displays hyphens (--) if the ARP entry does not belong to any VSI.
Service instance	Ethernet service instance in an ARP entry. This field displays hyphens (--) if no Ethernet service instance is specified for the Layer 2 Ethernet interface or Layer 2 aggregate interface in the ARP entry.
VXLAN ID	This field is not supported in the current software version. VXLAN ID (also called VNI). This field displays hyphens (--) if the ARP entry does not belong to any VXLAN.
VSI name	This field is not supported in the current software version. Name of the VSI to which the ARP entry belongs. This field displays hyphens (--) if the ARP entry does not belong to a specific VSI.
VSI interface	This field is not supported in the current software version. VSI interface specified for the VSI. This field displays hyphens (--) if no VSI interface is specified for the VSI.
Total number of entries	Number of ARP entries.

‌

Related commands

arp static

reset arp

display arp entry-limit

Use display arp entry-limit to display the maximum number of ARP entries that a device supports.

Syntax

display arp entry-limit

Views

Any view

Predefined user roles

network-admin

network-operator

Examples

# Display the maximum number of ARP entries that the device supports.

<Sysname> display arp entry-limit

ARP entries: 15360

display arp ip-address

Use display arp ip-address to display the ARP entry for an IP address.

Syntax

display arp ip-address [ verbose ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

ip-address: Displays the ARP entry for the specified IP address.

verbose: Displays the detailed information about the specified ARP entry.

Usage guidelines

The ARP entry information includes the IP address, MAC address, VLAN ID, output interface, entry type, and aging timer.

Examples

# Display the ARP entry for the IP address 20.1.1.1.

<Sysname> display arp 20.1.1.1

Type: S-Static D-Dynamic O-Openflow R-Rule I-Invalid

IP address MAC address VLAN/VSI name Interface Aging Type

20.1.1.1 00e0-fc00-0001 N/A -- -- S

Related commands

arp static

reset arp

display arp timer aging

Use display arp timer aging to display the aging timer of dynamic ARP entries.

Syntax

display arp timer aging

Views

Any view

Predefined user roles

network-admin

network-operator

Usage guidelines

This command always displays the aging time in seconds no matter which unit you set in the arp timer aging command.

Examples

# Display the aging timer of dynamic ARP entries.

<Sysname> display arp timer aging

Current ARP aging time is 1200 seconds

Related commands

arp timer aging

display arp usage

Use display arp usage to display the ARP table usage.

Syntax

display arp usage

Views

Any view

Predefined user roles

network-admin

network-operator

Usage guidelines

This command displays the maximum number of ARP entries supported on the device in addition to the history ARP table usage. You can use this command to monitor the number of ARP entries on the device and to determine whether ARP flood attacks exist on the network.

The device can display the ARP table usage only in the most recent hour.

Examples

# Display the ARP table usage.

<Sysname> display arp usage

ARP table upper limit: 65000

Time ARP entry count Usage

Current 52000 80%

1 min ago 51351 79%

2 min ago 50711 78%

3 min ago 47748 77%

…

59 min ago 13656 21%

60 min ago 13007 20%

Table 2 Command output

Field	Description
ARP table upper limit	Maximum number of ARP entries supported on the device.
Time	Time when the number of ARP entries were counted. This field displays Current if the number of ARP entries were counted just now.
ARP entry count	Number of ARP entries.
Usage	ARP table usage, which is the ratio of the real-time ARP entry count to the ARP table upper limit.

display arp user-ip-conflict record

Use display arp user-ip-conflict record to display user IP address conflict records.

Syntax

display arp user-ip-conflict record

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

Usage guidelines

Each device can save a maximum of 200 user IP address conflict records.

If the maximum number is reached, a new record will override the earliest record.

Examples

# Display all user IP address conflict records.

<Sysname> display arp user-ip-conflict record

IP address: 10.1.1.1

System time: 2018-02-02 11:22:29

Conflict count: 1

Log suppress count: 0

Old interface: GigabitEthernet1/0/1

New interface: GigabitEthernet1/0/2

Old SVLAN/CVLAN: 100/2

New SVLAN/CVLAN: 100/2

Old MAC: 00e0-ca63-8141

New MAC: 00e0-ca63-8142

IP address: 10.1.1.2

System time: 2018-02-02 10:20:30

Conflict count: 1

Log suppress count: 0

Old interface: GigabitEthernet1/0/1

New interface: GigabitEthernet1/0/2

Old SVLAN/CVLAN: 100/--

New SVLAN/CVLAN: 100/--

Old MAC: 00e0-ca63-8141

New MAC: 00e0-ca63-8142

Table 3 Command output

Field	Description
IP address	IP address of a user.
System time	Time when the user IP address conflict occurred.
Conflict count	Number of times that conflicts for the IP address.
Log suppress count	Number of times that user IP address conflict logs are suppressed.
Old interface	Output interface in the old ARP entry.
New interface	Output interface in the new ARP entry.
Old SVLAN/CVLAN	ID of the outer VLAN or inner VLAN in the old ARP entry. This field displays hyphens (--) if the ARP entry does not belong to any outer VLAN or inner VLAN.
New SVLAN/CVLAN	ID of the outer VLAN or inner VLAN in the new ARP entry. This field displays hyphens (--) if the ARP entry does not belong to any outer VLAN or inner VLAN.
Old MAC	MAC address in the old ARP entry.
New MAC	MAC address in the new ARP entry.

Related commands

arp user-ip-conflict record enable

display arp user-move record

Use display arp user-move record to display user port migration records.

Syntax

display arp user-move record

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

Usage guidelines

Each device can save a maximum of 200 user port migration records.

When the number of user port migration records reaches the upper limit, new records will overwrite the earliest ones.

Examples

# Display all user port migration records.

<Sysname> display arp user-move record

IP address: 10.1.1.1

MAC address: 0001-0201-0e81

System time: 2018-02-02 11:22:29

Move count: 1

Log suppress count: 0

Before:

interface: GigabitEthernet1/0/1

SVLAN/CVLAN: 100/2

After:

interface: GigabitEthernet1/0/2

SVLAN/CVLAN: 100/2

IP address: 10.1.1.2

MAC address: 0001-0201-0e82

System time: 2018-02-02 10:20:30

Move count: 1

Log suppress count: 0

Before:

interface: GigabitEthernet1/0/1

SVLAN/CVLAN: 100/--

After:

interface: GigabitEthernet1/0/2

SVLAN/CVLAN: 100/--

Table 4 Command output

Field	Description
IP address	IP address of the user.
MAC address	MAC address of the user.
System time	Time when the user port migration occurred.
Move count	Number of times that user port migrated.
Log suppress count	Number of times that the generation of user port migration logs is suppressed.
Interface	Output interface in the ARP entry.
SVLAN/CVLAN	ID of the outer VLAN or inner VLAN in the ARP entry. This field displays hyphens (--) if the ARP entry does not belong to any outer VLAN or inner VLAN.

Related commands

arp user-move record enable

reset arp

Use reset arp to clear ARP entries from the ARP table.

Syntax

reset arp { all | dynamic | interface interface-type interface-number | static }

Views

User view

Predefined user roles

network-admin

Parameters

all: Clears all ARP entries.

dynamic: Clears all dynamic ARP entries.

static: Clears all static ARP entries.

interface interface-type interface-number: Specifies an interface by its type and number. If you do not specify an interface, this command clears ARP entries for all interfaces.

Usage guidelines

CAUTION:

The reset arp command will clear existing ARP entries from the ARP table. It might cause that external users cannot quickly communicate with the LAN users.

Examples

# Clear all static ARP entries.

<Sysname> reset arp static

Related commands

arp static

display arp

Gratuitous ARP commands

arp ip-conflict log prompt

Use arp ip-conflict log prompt to enable IP conflict notification.

Use undo arp ip-conflict log prompt to restore the default.

Syntax

arp ip-conflict log prompt

undo arp ip-conflict log prompt

Default

IP conflict notification is disabled.

Views

System view

Predefined user roles

network-admin

Usage guidelines

By default, the device performs the following operations if it is using the sender IP address of a received ARP packet:

· Sends a gratuitous ARP request.

· Displays an error message after the device receives an ARP reply about the conflict.

You can use this command to enable the device to display error messages before sending a gratuitous ARP reply or request for conflict confirmation.

Examples

# Enable IP conflict notification on the device.

<Sysname> system-view

[Sysname] arp ip-conflict log prompt

arp send-gratuitous-arp

Use arp send-gratuitous-arp to enable periodic sending of gratuitous ARP packets on an interface.

Use undo arp send-gratuitous-arp to disable the interface from periodically sending gratuitous ARP packets.

Syntax

arp send-gratuitous-arp [ interval interval ]

undo arp send-gratuitous-arp

Default

Periodic sending of gratuitous ARP packets is disabled.

Views

VLAN interface view

Predefined user roles

network-admin

Parameters

interval interval: Specifies the sending interval in the range of 200 to 200000 milliseconds. The default value is 2000 milliseconds.

Usage guidelines

This feature takes effect on an interface only when the interface has an IP address and the data link layer state of the interface is up.

This feature can send gratuitous ARP requests only for the sending interface's primary IP address or manually configured secondary IP address. The primary IP address can be configured manually or automatically, whereas the secondary IP address must be configured manually.

If you change the sending interval for gratuitous ARP packets, the configuration takes effect at the next sending interval.

The sending interval for gratuitous ARP packets might be much longer than the set interval when any of the following conditions exist:

· This feature is enabled on multiple interfaces.

· Each interface is configured with multiple secondary IP addresses.

· A small sending interval is configured in the preceding cases.

Examples

# Enable VLAN-interface 2 to send gratuitous ARP packets every 300 milliseconds.

<Sysname> system-view

[Sysname] interface vlan-interface 2

[Sysname-Vlan-interface2] arp send-gratuitous-arp interval 300

gratuitous-arp mac-change retransmit

Use gratuitous-arp mac-change retransmit to set the times and the interval for retransmitting a gratuitous ARP packet for the device MAC address change.

Use undo gratuitous-arp mac-change retransmit to restore the default.

Syntax

gratuitous-arp mac-change retransmit times interval seconds

undo gratuitous-arp mac-change retransmit

Default

The device sends a gratuitous packet for its MAC address change once only.

Views

System view

Predefined user roles

network-admin

Parameters

times: Specifies the times of retransmitting a gratuitous packet, in the range of 1 to 10.

interval seconds: Specifies the interval for retransmitting a gratuitous packet, in the range of 1 to 10 seconds.

Usage guidelines

The device sends a gratuitous ARP packet to inform other devices of its MAC address change. However, the other devices might fail to receive the packet because the device sends the gratuitous ARP packet once only by default. Use this command to configure gratuitous ARP retransmission parameters to ensure that the other devices can receive the packet.

After you execute this command, the device will retransmit a gratuitous ARP packet for its MAC address change at the specified interval for the specified times.

Examples

# Set the times to 3 and the interval to 5 for retransmitting a gratuitous ARP packet for the device MAC address change.

<Sysname> system-view

[Sysname] gratuitous-arp mac-change retransmit 3 interval 5

gratuitous-arp-learning enable

Use gratuitous-arp-learning enable to enable learning of gratuitous ARP packets.

Use undo gratuitous-arp-learning enable to disable learning of gratuitous ARP packets.

Syntax

gratuitous-arp-learning enable

undo gratuitous-arp-learning enable

Default

Learning of gratuitous ARP packets is enabled.

Views

System view

Predefined user roles

network-admin

Usage guidelines

The learning of gratuitous ARP packets feature allows a device to maintain its ARP table by creating or updating ARP entries based on received gratuitous ARP packets.

When this feature is disabled, the device uses received gratuitous ARP packets to update existing ARP entries only. ARP entries are not created based on the received gratuitous ARP packets, which saves ARP table space.

Examples

# Enable learning of gratuitous ARP packets.

<Sysname> system-view

[Sysname] gratuitous-arp-learning enable

gratuitous-arp-sending enable

Use gratuitous-arp-sending enable to enable sending gratuitous ARP packets upon receiving ARP requests whose sender IP address is on a different subnet.

Use undo gratuitous-arp-sending enable to disable sending gratuitous ARP packets upon receiving ARP requests whose sender IP address is on a different subnet.

Syntax

gratuitous-arp-sending enable

undo gratuitous-arp-sending enable

Default

A device does not send gratuitous ARP packets when it receives ARP requests whose sender IP address is on a different subnet.

Views

System view

Predefined user roles

network-admin

Examples

# Disable a device from sending gratuitous ARP packets upon receiving ARP requests whose sender IP address is on a different subnet.

<Sysname> system-view

[Sysname] undo gratuitous-arp-sending enable

Proxy ARP commands

display local-proxy-arp

Use display local-proxy-arp to display the local proxy ARP status.

Syntax

display local-proxy-arp [ interface interface-type interface-number ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

interface interface-type interface-number: Specifies an interface by its type and number. If you do not specify an interface, this command displays the local proxy ARP status for all interfaces.

Usage guidelines

You can use this command to check whether local proxy ARP is enabled or disabled.

Examples

# Display the local proxy ARP status for VLAN-interface 2.

<Sysname> display local-proxy-arp interface vlan-interface 2

Interface Vlan-interface2

Local Proxy ARP status: enabled

Related commands

local-proxy-arp enable

display proxy-arp

Use display proxy-arp to display the proxy ARP status.

Syntax

display proxy-arp [ interface interface-type interface-number ]

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

interface interface-type interface-number: Specifies an interface by its type and number. If you do not specify an interface, this command displays the proxy ARP status for all interfaces.

Usage guidelines

You can use this command to check whether proxy ARP is enabled or disabled.

Examples

# Display the proxy ARP status on VLAN-interface 2.

<Sysname> display proxy-arp interface vlan-interface 2

Interface Vlan-interface2

Proxy ARP status: disabled

Related commands

proxy-arp enable

display proxy-arp statistics

Use display proxy-arp statistics to display statistics about proxy ARP reply packets.

Syntax

display proxy-arp statistics

Views

Any view

Predefined user roles

network-admin

network-operator

Usage guidelines

This command displays the proxy ARP reply statistics within the most recent minute on a per-second basis and displays the statistics one minute ago on a five-minute basis. The device can display the proxy ARP reply statistics in the most recent hour.

Examples

# Display proxy ARP reply statistics.

<Sysname> display proxy-arp statistics

Last 1 sec proxy count: 200

Last 2 sec proxy count: 400

...

Last 1 min proxy count: 12000

Last 5 min proxy count: 18000

Last 10 min proxy count: 24000

...

Last 60 min proxy count: 182445

Table 5 Command output

Field	Description
Last n sec proxy count:	Number of proxy ARP reply packets within the most recent nth second.
Last n min proxy count:	Number of proxy ARP reply packets within the most recent nth minute.

local-proxy-arp enable

Use local-proxy-arp enable to enable local proxy ARP.

Use undo local-proxy-arp enable to disable local proxy ARP.

Syntax

local-proxy-arp enable [ ip-range start-ip-address to end-ip-address ]

undo local-proxy-arp enable

Default

Local proxy ARP is disabled.

Views

VLAN interface view

Predefined user roles

network-admin

Parameters

ip-range start-ip-address to end-ip-address: Specifies the IP address range for which local proxy ARP is enabled. The start IP address must be lower than or equal to the end IP address.

Usage guidelines

Proxy ARP enables a device on a network to answer ARP requests for an IP address not on that network. With proxy ARP, hosts in different broadcast domains can communicate with each other as they do on the same network.

Proxy ARP includes common proxy ARP and local proxy ARP.

Common proxy ARP allows communication between hosts that connect to different Layer 3 interfaces and reside in different broadcast domains.

Local proxy ARP allows communication between hosts that connect to the same Layer 3 interface and reside in different broadcast domains.

If you execute this command multiple times, the most recent configuration takes effect.

Examples

# Enable local proxy ARP on VLAN-interface 2.

<Sysname> system-view

[Sysname] interface vlan-interface 2

[Sysname-Vlan-interface2] local-proxy-arp enable

# Enable local proxy ARP on VLAN-interface 2 for an IP address range.

<Sysname> system-view

[Sysname] interface vlan-interface 2

[Sysname-Vlan-interface2] local-proxy-arp enable ip-range 1.1.1.1 to 1.1.1.20

Related commands

display local-proxy-arp

proxy-arp enable

Use proxy-arp enable to enable proxy ARP.

Use undo proxy-arp enable to disable proxy ARP.

Syntax

proxy-arp enable

undo proxy-arp enable

Default

Proxy ARP is disabled.

Views

VLAN interface view

Predefined user roles

network-admin

Usage guidelines

Proxy ARP includes common proxy ARP and local proxy ARP.

Common proxy ARP allows communication between hosts that connect to different Layer 3 interfaces and reside in different broadcast domains.

Local proxy ARP allows communication between hosts that connect to the same Layer 3 interface and reside in different broadcast domains.

Examples

# Enable proxy ARP on VLAN-interface 2.

<Sysname> system-view

[Sysname] interface vlan-interface 2

[Sysname-Vlan-interface2] proxy-arp enable

Related commands

display proxy-arp

ARP snooping commands

arp snooping enable

Use arp snooping enable to enable ARP snooping.

Use undo arp snooping enable to disable ARP snooping.

Syntax

arp snooping enable

undo arp snooping enable

Default

ARP snooping is disabled.

Views

VLAN view

Predefined user roles

network-admin

Examples

# Enable ARP snooping for VLAN 2.

<Sysname> system-view

[Sysname] vlan 2

[Sysname-vlan2] arp snooping enable

display arp snooping

Use display arp snooping to display ARP snooping entries.

Syntax

display arp snooping { vlan [ vlan-id ] }

display arp snooping vlan ip ip-address

Views

Any view

Predefined user roles

network-admin

network-operator

Parameters

vlan vlan-id: Displays ARP snooping entries for a VLAN. The vlan-id argument is in the range of 1 to 4094. If you do not specify a VLAN, this command deletes ARP snooping entries for all VLANs.

ip ip-address: Displays the ARP snooping entry for the specified IP address.

Examples

# Display ARP snooping entries for VLAN 2.

<Sysname> display arp snooping vlan 2

IP Address MAC Address VLAN ID Interface Aging Status

3.3.3.3 0003-0003-0003 2 GE1/0/1 20 Valid

3.3.3.4 0004-0004-0004 2 GE1/0/2 5 Invalid

# Display the ARP snooping entry for IP address 1.1.1.1 in a VLAN.

<Sysname> display arp snooping vlan ip 1.1.1.1

IP address MAC address VLAN ID Interface Aging Status

1.1.1.1 001f-e201-0111 2 GE1/0/1 15 Valid

Table 6 Command output

Field	Description
IP Address	IP address in an ARP snooping entry.
MAC Address	MAC address in the ARP snooping entry.
VLAN ID	ID of the VLAN to which the ARP snooping entry belongs.
Interface	Input interface in the ARP snooping entry.
Aging	Aging time for the ARP snooping entry in minutes. If the card learns an ARP snooping entry from another card, the card cannot learn the aging time of the entry, and this field displays N/A.
Status	Status of the ARP snooping entry: Valid, Invalid, Collision.
Total entries	Number of ARP snooping entries.

Related commands

reset arp snooping

Use reset arp snooping to delete ARP snooping entries.

Syntax

reset arp snooping { vlan [ vlan-id ] }

reset arp snooping vlan ip ip-address

Views

User view

Predefined user roles

network-admin

Parameters

vlan vlan-id: Deletes ARP snooping entries for the specified VLAN. The value range for the vlan-id argument is 1 to 4094. If you do not specify a VLAN, this command deletes ARP snooping entries for all VLANs.

ip ip-address: Deletes the ARP snooping entry for the specified IP address.

Usage guidelines

If you do not specify any option, the command deletes all ARP snooping entries.

Examples

# Delete ARP snooping entries for VLAN 2.

<Sysname> reset arp snooping vlan 2

Related commands

display arp snooping

ARP fast-reply commands

arp fast-reply enable

Use arp fast-reply enable to enable ARP fast-reply for a VLAN.

Use undo arp fast-reply enable to disable ARP fast-reply for a VLAN.

Syntax

arp fast-reply enable

undo arp fast-reply enable

Default

ARP fast-reply is disabled on a VLAN.

Views

VLAN view

Predefined user roles

network-admin

Examples

# Enable ARP fast-reply for VLAN 2.

<Sysname> system-view

[Sysname] vlan 2

[Sysname-vlan2] arp fast-reply enable

05-Network Connectivity

arp static

arp timer aging

display arp ip-address

reset arp

gratuitous-arp-learning enable

display local-proxy-arp

display proxy-arp

local-proxy-arp enable

ARP snooping commands

display arp snooping

reset arp snooping

ARP fast-reply commands

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