Cisco Systems 78-11741-02 manual Monitoring and Maintaining the Dhcp Server, IPC-75

Configuring DHCP

Monitoring and Maintaining the DHCP Server

Configuring the Relay Agent Information Option in BOOTREPLY Messages

To configure the DHCP Server to validate the relay agent information option in forwarded BOOTREPLY messages, use the following command in global configuration mode:

Command	Purpose
Router(config)# ip dhcp relay information check	Configures the DHCP Server to check that the relay agent
	information option in forwarded BOOTREPLY messages is valid.

Configuring a Relay Agent Information Reforwarding Policy

To configure a relay agent information reforwarding policy on the DHCP Server (what the DHCP Server should do if a forwarded message already contains relay information), use the following command in global configuration mode:

Command	Purpose
Router(config)# ip dhcp relay information policy	Determines the relay information reforwarding policy in a cable
{drop keep replace}	modem termination system.

Enabling the DHCP Smart-Relay Feature

By default, the DHCP smart-relay feature is disabled. To enable the smart-relay functionality, use the following command in global configuration mode:

Command	Purpose
Router(config)# ip dhcp smart-relay	Allows the DHCP relay agent to switch the gateway address
	(giaddr field of a DHCP packet) to secondary addresses when
	there is no DHCPOFFER message from a DHCP Server.

Monitoring and Maintaining the DHCP Server

To clear DHCP Server variables, use the following commands in privileged EXEC mode, as needed:

Command	Purpose
Router# clear ip dhcp binding {address *}	Deletes an automatic address binding from the DHCP database.
	Specifying the address argument clears the automatic binding for a
	specific (client) IP address, whereas specifying an asterisk (*) clears
	all automatic bindings.
Router# clear ip dhcp conflict {address *}	Clears an address conflict from the DHCP database. Specifying the
	address argument clears the conflict for a specific IP address, whereas
	specifying an asterisk (*) clears conflicts for all addresses.

Cisco IOS IP Configuration Guide

IPC-75