D-Link DXS-3600 Series Cli Reference Manual page 328

DXS-3600 Series Layer 3 Managed 10Gigabit Ethernet Switch CLI Reference Guide
This command is used to enable the DHCP relay agent to validate and remove the relay agent
information option in the received DHCP reply packet. Use the no form of the command to globally
disable the check for Option 82.
ip dhcp relay information check
no ip dhcp relay information check
Parameters
None.
Default
By default, this option is disabled.
Command Mode
Global Configuration Mode.
Command Default Level
Level: 12.
Usage Guideline
This command takes effect when the DHCP service is enabled.
The ip dhcp relay information check command and the ip dhcp relay information check-reply
command together determine whether the check function of Option 82 is effective for an interface. If the
ip dhcp relay information check-reply command is not configured for an interface, the global setting
takes effect. If the ip dhcp relay information check-reply command is configured for an interface, the
interface setting takes effect.
When the check for Option 82 of the reply packet is enabled, the device will check the validity of the
Option 82 field in DHCP reply packets it receives from the DHCP server. If the Option 82 field in the
received packet is not present or the option is not the original option inserted by the agent (by checking
the remote ID sub-option), the relay agent drops the packet. Otherwise, the relay agent removes the
Option 82 field and forwards the packet.
If the check is disabled, the packet will be directly forwarded.
Example
This example shows how to enable the global DHCP relay agent check.
Switch# configure terminal
Switch(config)# ip dhcp relay information check
Switch(config)#
21-3 ip dhcp relay information check-reply
This command is used to configure the DHCP relay agent to validate the relay agent information option in
the received DHCP reply packet. Use the no form of the command to remove the configuration for the
interface.
ip dhcp relay information check-reply [none]
no ip dhcp relay information check-reply [none]
Parameters
323