Administrator Guide

Protocol Address Age(min) Hardware Address Interface VLAN CPU
--------------------------------------------------------------------------------
Internet 10.1.2.4 17 08:00:20:b7:bd:32 Ma 1/0 - CP
Dell#
Configuring ARP Inspection Trust
Use the arp-inspection-trust command to specify a port or an interface as trusted so that ARP frames are not validated against
the binding table. By default, this feature is disabled.
• Enable ARP learning via gratuitous ARP.
INTERFACE Mode
INTERFACE PORT-CHANNEL Mode
INTERFACE PORT EXTENDER Mode
arp-inpsecton-trust
Dell(conf)#int peGigE 0/0/0
Dell(conf-if-pegi-0/0/0)# arp-inpsection-trust
Configuring ARP Timeout
Use the arp backoff-timer command for setting the exponential timer for resending unresolved ARPs.
• Set the exponential timer for resending unresolved ARPs.
CONFIGURATION Mode
arp backoff-time seconds / minutes
Enter the number of seconds an ARP entry is black-holed. The range is from 1 to 3600. The default is 30 minutes.
Enter the number of minutes an ARP entry is balck-holed. The range is from 0 to 35790. The default is 4 hours.
Dell(conf)#arp backoff-time minutes
Enabling Proxy ARP
By default, Proxy ARP is enabled. To disable Proxy ARP, use the no ip proxy-arp command in the interface mode.
To re-enable Proxy ARP, use the following command.
• Re-enable Proxy ARP.
INTERFACE mode
ip proxy-arp
To view if Proxy ARP is enabled on the interface, use the show config command in INTERFACE mode. If it is not listed in the show
config command output, it is enabled. Only non-default information is displayed in the show config command output.
Clearing ARP Cache
To clear the ARP cache of dynamically learnt ARP information, use the following command.
• Clear the ARP caches for all interfaces or for a specific interface by entering the following information.
EXEC privilege
clear arp-cache [interface | ip ip-address] [no-refresh]
• ip ip-address (OPTIONAL): enter the keyword ip then the IP address of the ARP entry you wish to clear.
• no-refresh (OPTIONAL): enter the keywords no-refresh to delete the ARP entry from CAM. Or to specify which dynamic
ARP entries you want to delete, use this option with interface or ip ip-address.
• For a port channel interface, enter the keywords port-channel then a number.
• For a 10-Gigabit Ethernet interface, enter the keyword TenGigabitEthernet then the slot/port information.
IPv4 Routing
441