Clearing ARP CacheTo 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 privilegeclear 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 dynamicARP entries you want to delete, use this option with interface or ip ip-address.• For a 10-Gigabit Ethernet interface, enter the keyword TenGigabitEthernet then the slot/port[/subport] information.• For a 40-Gigabit Ethernet interface, enter the keyword fortyGigE then the slot/port information.• For a port channel interface, enter the keywords port-channel then a number.• For a VLAN interface, enter the keyword vlan then a number from 1 to 4094.NOTE: Transit traffic may not be forwarded during the period when deleted ARP entries are resolved again and re-installed inCAM. Use this option with extreme caution.ARP Learning via Gratuitous ARPGratuitous ARP can mean an ARP request or reply.In the context of ARP learning via gratuitous ARP on Dell Networking OS, the gratuitous ARP is a request. A gratuitous ARP request is anARP request that is not needed according to the ARP specification, but one that hosts may send to:• detect IP address conflicts• inform switches of their presence on a port so that packets can be forwarded• update the ARP table of other nodes on the network in case of an address changeIn the request, the host uses its own IP address in the Sender Protocol Address and Target Protocol Address fields.Enabling ARP Learning via Gratuitous ARPTo enable ARP learning via gratuitous ARP, use the following command.• Enable ARP learning via gratuitous ARP.CONFIGURATION modearp learn-enableARP Learning via ARP RequestIn Dell Networking OS versions prior to 8.3.1.0, Dell Networking OS learns via ARP requests only if the target IP specified in the packetmatches the IP address of the receiving router interface. This is the case when a host is attempting to resolve the gateway address.If the target IP does not match the incoming interface, the packet is dropped. If there is an existing entry for the requesting host, it isupdated.IPv4 Routing 443
