Owners manual

DGS-1510 Series Gigabit Ethernet SmartPro Switch CLI Reference Guide
273
Command Default Level
Level: 12.
Usage Guideline
A gratuitous ARP request packet is an ARP request packet where the source and the destination IP
address are both set to the IP address of the sending device and the destination MAC address is the
broadcast address.
Generally, a device use the gratuitous ARP request packet to discover whether the IP address is
duplicated by other hosts or to preload or reconfigure the ARP cache entry of hosts connected to the
interface.
Use the ip gratuitous-arps command to enable transmission of gratuitous ARP request. The device will
send out the packet when an IP interface becomes link-up or when the IP address of an interface is
configured or modified.
Use the ip gratuitous-arps dad-reply command to enable the transmission of gratuitous ARP requests.
The device will send out the packet while a duplicate IP address is detected
Example
This example shows how to sending of gratuitous ARP messages.
Switch# configure terminal
Switch(config)# ip gratuitous-arps dad-reply
switch(config)#
30-3 arp gratuitous-send
This command is used to set the interval for regularly sending of gratuitous ARP request messages on
the interface. Use no command to disable this function on the interface.
arp gratuitous-send interval SECONDS
no arp gratuitous-send
Parameters
SECONDS
Specifies the time interval to send the gratuitous ARP request
message in the range from 1 to 3600 seconds.
Default
By default, this option is disabled.
Command Mode
Interface Configuration Mode.
Command Default Level
Level: 12.
Usage Guideline
If an interface on the Switch is used as the gateway of its downlink devices and counterfeit gateway
behavior occurs in the downlink devices, administrators can configure to send gratuitous ARP request
messages regularly on this interface to notify that the Switch is the real gateway.
Example
This example shows how to enable the sending of gratuitous ARP messages.