1-7[Switch-vlan-interface10] ip address 192.168.1.2 8[Switch-vlan-interface10] quit# Configure a static ARP entry with IP address 192.168.1.1 and MAC address 00e0-fc01-0000. Theoutgoing interface corresponding to the static ARP entry is GigabitEthernet 2/0/1 belonging to VLAN10.[Switch] arp static 192.168.1.1 00e0-fc01-0000 10 GigabitEthernet 2/0/1# View information about static ARP entries.[Switch] display arp staticType: S-Static D-Dynamic A-AuthorizedIP Address MAC Address VLAN ID Interface Aging Type192.168.1.1 00e0-fc01-0000 10 GE2/0/1 N/A SConfiguring Gratuitous ARPIntroduction to Gratuitous ARPIn a gratuitous ARP packet, the sender IP address and the target IP address are both the IP address ofthe device issuing the packet, the sender MAC address is the MAC address of the device, and thetarget MAC address is the broadcast address ff:ff:ff:ff:ff:ff.A device implements the following functions by sending gratuitous ARP packets:z Determining whether its IP address is already used by another device. If the IP address is alreadyused, the device issuing the gratuitous ARP packet will be informed by an ARP reply of the conflict.z Informing other devices about the change of its MAC address so that they can update their ARPentries.Enabling Learning of Gratuitous ARP PacketsWith this feature enabled, a device receiving a gratuitous ARP packet adds the sender IP and MACaddresses carried in the packet to its ARP table if no corresponding ARP entry exists. If acorresponding ARP entry is found, the device updates the ARP entry.After this feature is disabled, the device will use the address information in the received gratuitous ARPpackets to update the existing ARP entries only, but not to create new ARP entries.Configuring Gratuitous ARPFollow these steps to configure gratuitous ARP:To do… Use the command… RemarksEnter system view system-view —Enable the device to sendgratuitous ARP packets whenreceiving ARP requests fromanother network segmentgratuitous-arp-sendingenableRequiredBy default, a device cannotsend gratuitous ARP packetswhen receiving ARP requestsfrom another network segment.Enable the gratuitous ARPpacket learning functiongratuitous-arp-learningenableOptionalEnabled by default.
