1-5 
 
z  Static ARP entries are valid as long as the Ethernet switch operates normally. But some operations, 
such as removing a VLAN, or removing a port from a VLAN, will make the corresponding ARP 
entries invalid and therefore removed automatically. 
z  As for the arp static command, the value of the vlan-id argument must be the ID of an existing 
VLAN, and the port identified by the interface-type and interface-number arguments must belong to 
the VLAN. 
z  Currently, static ARP entries cannot be configured on the ports of an aggregation group. 
 
Configuring Gratuitous ARP 
Follow these steps to configure gratuitous ARP: 
To do…  Use the command…  Remarks 
Enter system view 
system-view 
— 
Enable the gratuitous ARP 
packet learning function 
gratuitous-arp-learning 
enable 
Optional 
Enabled by default. 
 
 
The sending of gratuitous ARP packets is enabled as long as an S4200G switch operates. No 
command is needed for enabling this function. That is, the device sends gratuitous ARP packets 
whenever a VLAN interface is enabled (such as when a link is enabled or an IP address is configured 
for the VLAN interface) or whenever the IP address of a VLAN interface is changed. 
 
Displaying and Debugging ARP 
To do…  Use the command…  Remarks 
Display specific ARP mapping 
table entries 
display arp [ static | dynamic | ip-address ] 
Display the ARP mapping 
entries related to a specified 
string in a specified way 
display arp [ dynamic | static ] | { begin | 
include | exclude } regular-expression 
Display the number of the ARP 
entries of a specified type 
display arp count [ [ dynamic | static ] [ | 
{ begin | include | exclude } 
regular-expression ] | ip-address ] 
Display the statistics about the 
untrusted ARP packets 
dropped by the specified port 
display arp detection statistics interface 
interface-type interface-number 
Display the setting of the ARP 
aging timer 
display arp timer aging 
Available in 
any view