Netgear XCM8806 Chassis Hardware Installation Guide - Page 566

NETGEAR 8800 Chassis Switch CLI Manual Description Enables the Dynamic Host Configuration Protocol (DHCP) relay agent option (option 82) checking in the server-originated packets. Syntax Description This command has no arguments or variables. Default N/A. Usage Guidelines This command enables the checking of the server-originated packets for the presence of option 82. In some instances, a DHCP server may not properly handle a DHCP request packet containing a relay agent option. Use this command to prevent DHCP reply packets with invalid or missing relay agent options from being forwarded to the client. With checking enabled, the following checks and actions are performed: • When the option 82 is present in the packet, the MAC address specified in the remote-ID sub-option is the switch system MAC address. If the check fails, the packet is dropped. • When option 82 is not present in the packet, the DHCP packet is forwarded with no modification. To disable this check, use the following command: unconfigure ip-security dhcp-snooping information check Example The following command enables DHCP relay agent option checking: configure ip-security dhcp-snooping information check configure ip-security dhcp-snooping information circuit-id port-information port configure ip-security dhcp-snooping information circuit-id port-information port Description Configures the port information portion of the circuit ID. Syntax Description port_info port Specifies the circuit ID port information in the format of - ; maximum length is 32 bytes. Specifies the port for which DHCP Snooping should be enabled. 566 | Chapter 15. Security Commands