Ip Dhcp Relay Information Option - D-Link DXS-3600 Series Reference Manual

DXS-3600 Series Layer 3 Managed 10Gigabit Ethernet Switch CLI Reference Guide
none
Default
None.
Command Mode
Interface Configuration Mode.
Command Default Level
Level: 12.
Usage Guideline
This command only 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 disable the global DHCP relay agent check but enables the DHCP relay
agent check for the VLAN 100. The effect state of the check function for VLAN100 is enabled.
Switch# configure terminal
Switch(config)# no ip dhcp relay information check
switch(config)# interface vlan 100
switch(config-if)# ip dhcp relay information check-reply

20-4 ip dhcp relay information option

This command is used to enable the insertion of relay agent information (Option 82) during the relay of
DHCP request packets. Use the no command to disable this insert function.
ip dhcp relay information option
no ip dhcp relay information option
Parameters
None.
Default
By default, Option 82 is not inserted.
Command Mode
Global Configuration Mode.
Command Default Level
Specifies to disable check for Option 82 of the reply packet.
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