Netgear XCM8810 Chassis User Manual - Page 458

NETGEAR 8800 User Manual By default, DHCP secured ARP learning is disabled. To enable DHCP secured ARP, use the following command: enable ip-security arp learning learn-from-dhcp {vlan} ports [all | ] DHCP Secured ARP must be enabled on the DHCP server port as well as the DHCP client ports. To disable DHCP secured ARP, use the following command: disable ip-security arp learning learn-from-dhcp {vlan} ports [all | ] Note: You must enable DHCP secured ARP on the DHCP server as well as on the client ports. DHCP snooping, as always, must also be enabled on both the server and client ports. Displaying ARP Information To display how the switch builds an ARP table and learns MAC addresses for devices on a specific VLAN and associated member ports, use the following command: show ip-security arp learning {vlan} The following is sample output from this command: Port Learn-from 2:1 ARP 2:2 DHCP 2:3 ARP 2:4 None 2:5 ARP 2:6 ARP 2:7 ARP 2:8 ARP To view the ARP table, including permanent and DHCP secured ARP entries, use the following command: show iparp { | | vlan | permanent} {vr } Note: DHCP secured ARP entries are stored as static entries in the ARP table. Gratuitous ARP Protection When a host sends an ARP request to resolve its own IP address it is called gratuitous ARP. A gratuitous ARP request is sent with the following parameters: 458 | Chapter 17. Security