18-ARP Commands
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Syntax
arp check enable
undo arp check enable
View
System view
Default Level
2: System level
Parameters
None
Description
Use the arp check enable command to enable ARP entry check. With this function enabled, the device cannot learn any ARP entry with a multicast MAC address. Configuring such a static ARP entry is not allowed either; otherwise, the system displays error messages.
Use the undo arp check enable command to disable the function. After the ARP entry check is disabled, the device can learn the ARP entry with a multicast MAC address, and you can also configure such a static ARP entry on the device.
By default, ARP entry check is enabled.
Examples
# Enable ARP entry check.
<Sysname> system-view
[Sysname] arp check enable
Syntax
arp max-learning-num number
undo arp max-learning-num
View
Layer 2 Ethernet interface view, VLAN interface view, Layer 2 aggregate interface
Default Level
2: System level
Parameters
number: Maximum number of dynamic ARP entries that an interface can learn,in the range 0 to 256.
Description
Use the arp max-learning-num command to configure the maximum number of dynamic ARP entries that an interface can learn.
Use the undo arp max-learning-num command to restore the default.
By default, the maximum number of dynamic ARP entries that an interface can learn is 256.
Examples
# Specify VLAN-interface 40 to learn up to 500 dynamic ARP entries.
<Sysname> system-view
[Sysname] interface vlan-interface 40
[Sysname-Vlan-interface40] arp max-learning-num 500
# Specify GigabitEthernet 1/1/1 to learn up to 100 dynamic ARP entries.
<Sysname> system-view
[Sysname] interface GigabitEthernet 1/1/1
[Sysname-GigabitEthernet1/1/1] arp max-learning-num 100
Syntax
arp static ip-address mac-address [ vlan-id interface-type interface-number ]
undo arp ip-address
View
System view
Default Level
2: System level
Parameters
ip-address: IP address in an ARP entry.
mac-address: MAC address in an ARP entry, in the format H-H-H.
vlan-id: ID of a VLAN to which a static ARP entry belongs to, in the range 1 to 4094.
interface-type interface-number: Interface type and interface number.
Description
Use the arp static command to configure a static ARP entry in the ARP mapping table.
Use the undo arp command to remove an ARP entry.
Note that:
l A static ARP entry is effective when the device works normally. However, when the VLAN or VLAN interface to which an ARP entry corresponds is deleted, the entry, if permanent, will be deleted, and if non-permanent and resolved, will become unresolved.
l The vlan-id argument is used to specify the corresponding VLAN of an ARP entry and must be the ID of an existing VLAN. In addition, the Ethernet interface following the argument must belong to that VLAN. The VLAN interface of the VLAN must have been created.
Related commands: reset arp, display arp.
Examples
# Configure a static ARP entry, with the IP address being 202.38.10.2, the MAC address being 00e0-fc01-0000, and the outbound interface being GigabitEthernet 1/1/1 of VLAN 10.
<Sysname> system-view
[Sysname] arp static 202.38.10.2 00e0-fc01-0000 10 GigabitEthernet 1/1/1
Syntax
arp timer aging aging-time
undo arp timer aging
View
System view
Default Level
2: System level
Parameters
aging-time: Aging time for dynamic ARP entries in minutes, in the range 1 to 1,440.
Description
Use the arp timer aging command to set aging time for dynamic ARP entries.
Use the undo arp timer aging command to restore the default.
By default, the aging time for dynamic ARP entries is 20 minutes.
Related commands: display arp timer aging.
Examples
# Set aging time for dynamic ARP entries to 10 minutes.
<Sysname> system-view
Syntax
display arp [ [ all | dynamic | static ] | vlan vlan-id | interface interface-type interface-number ] [ [ | { begin | exclude | include } regular-expression ] | count ]
View
Any view
Default Level
1: Monitor level
Parameters
all: Displays all ARP entries.
dynamic: Displays dynamic ARP entries.
static: Displays static ARP entries.
vlan vlan-id: Displays the ARP entries of the specified VLAN. The VLAN ID ranges from 1 to 4,094.
interface interface-type interface-number: Displays the ARP entries of the interface specified by the argument interface-type interface-number.
|: Uses a regular expression to specify the ARP entries to be displayed. For detailed information about regular expressions, refer to Basic System Configuration.
begin: Displays ARP entries from the first one containing the specified string.
exclude: Displays the ARP entries that do not contain the specified string.
include: Displays the ARP entries containing the specified string.
regular-expression: A case-sensitive string for matching, consisting of 1 to 256 characters.
count: Displays the number of ARP entries.
Description
Use the display arp command to display ARP entries in the ARP mapping table.
If no parameter is specified, all ARP entries are displayed.
Related commands: arp static, reset arp.
Examples
# Display the detailed information of all ARP entries.
Type: S-Static D-Dynamic
IP Address MAC Address VLAN ID Interface Aging Type
192.168.0.57 00e0-fc00-000b 1 GE1/1/3 20 D
192.168.0.38 000f-3456-9112 1 GE1/1/3 20 D
192.168.0.30 00e0-fc00-0021 1 GE1/1/3 20 D
Table 1-1 display arp command output description
|
Field |
Description |
|
IP Address |
IP address in an ARP entry |
|
MAC Address |
MAC address in an ARP entry |
|
VLAN ID |
VLAN ID contained a static ARP entry |
|
Interface |
Outbound interface in an ARP entry |
|
Aging |
Aging time for a dynamic ARP entry in minutes (“N/A” means unknown aging time or no aging time) |
|
Type |
ARP entry type: D for dynamic, S for static |
# Display the number of all ARP entries.
<Sysname> display arp all count
Total Entry(ies): 3
Syntax
display arp ip-address [ | { begin | exclude | include } regular-expression ]
View
Any view
Default Level
1: Monitor level
Parameters
ip-address: Displays the ARP entry for the specified IP address.
|: Uses a regular expression to specify the ARP entries to be displayed. For detailed information about regular expressions, refer to Basic System Configuration.
begin: Displays the ARP entries from the first one containing the specified string.
exclude: Displays the ARP entries that do not contain the specified string.
include: Displays the ARP entries that contain the specified string.
regular-expression: A case-sensitive string for matching, consisting of 1 to 256 characters.
Description
Use the display arp ip-address command to display the ARP entry for a specified IP address.
Related commands: arp static, reset arp.
Examples
# Display the corresponding ARP entry for the IP address 20.1.1.1.
<Sysname> display arp 20.1.1.1
Type: S-Static D-Dynamic
IP Address MAC Address VLAN ID Interface Aging Type
20.1.1.1 00e0-fc00-0001 N/A N/A N/A S
Syntax
display arp timer aging
View
Any view
Default Level
2: System level
Parameters
None
Description
Use the display arp timer aging command to display the aging time for dynamic ARP entries.
Related commands: arp timer aging.
Examples
# Display the aging time for dynamic ARP entries.
<Sysname> display arp timer aging
Current ARP aging time is 10 minute(s)
Syntax
reset arp { all | dynamic | static | interface interface-type interface-number }
View
User view
Default Level
2: System level
Parameters
all: Clears all ARP entries except authorized ARP entries.
dynamic: Clears all dynamic ARP entries.
static: Clears all static ARP entries.
interface interface-type interface-number: Clears the ARP entries for the interface specified by the argument interface-type interface-number.
Description
Use the reset arp command to clear ARP entries except authorized ARP entries from the ARP mapping table.
With interface interface-type interface-number specified, the command clears only dynamic ARP entries of the interface.
Related commands: arp static, display arp.
Examples
# Clear all static ARP entries.
<Sysname> reset arp static
Syntax
gratuitous-arp-sending enable
undo gratuitous-arp-sending enable
View
System view
Default Level
2: System level
Parameters
None
Description
Use the gratuitous-arp-sending enable command to enable a device to send gratuitous ARP packets when receiving ARP requests from another network segment.
Use the undo gratuitous-arp-sending enable command to restore the default.
By default, a device cannot send gratuitous ARP packets when receiving ARP requests from another network segment.
Examples
# Disable a device from sending gratuitous ARP packets.
<Sysname> system-view
[Sysname] undo gratuitous-arp-sending enable
Syntax
gratuitous-arp-learning enable
undo gratuitous-arp-learning enable
View
System view
Default Level
2: System level
Parameters
None
Description
Use the gratuitous-arp-learning enable command to enable the gratuitous ARP packet learning function.
Use the undo gratuitous-arp-learning enable command to disable the function.
By default, the function is enabled.
With this function enabled, a device receiving a gratuitous ARP packet can add the source IP and MAC addresses carried in the packet to its own dynamic ARP table if it finds no ARP entry in the cache corresponding to the source IP address of the ARP packet exists; if the corresponding ARP entry exists in the cache, the device updates the ARP entry regardless of whether this function is enabled.
Examples
# Enable the gratuitous ARP packet learning function.
<Sysname> system-view
[Sysname] gratuitous-arp-learning enable
