D-Link DGS-3700 Series User Manual page 35

DGS-3700-12/DGS-3700-12G Series Layer 2 Gigabit Ethernet Switch User Manual
DHCP Relay Agent
Information Option 82
Check
DHCP Relay Agent
Information Option 82
Policy
DHCP Relay Option
60 State
DHCP Relay Option
61 State
Click Apply to implement any changes that have been made.
NOTE: If the Switch receives a packet that contains the option-82 field from a DHCP client and the
information-checking feature is enabled, the switch drops the packet because it is invalid. However, in
some instances, you might configure a client with the option-82 field. In this situation, you should
disable the information-check feature so that the switch does not remove the option-82 field from the
packet. You can configure the action that the switch takes when it receives a packet with existing
option-82 information by configuring the DHCP Agent Information Option 82 Policy.
DHCP relay information (option 82 field) in messages between DHCP servers and clients,
and the check and policy settings will have no effect.
This field can be toggled between Enabled and Disabled using the pull-down menu. It is
used to enable or disable the Switches ability to check the validity of the packet's option 82
field.
Enabled – When the field is toggled to Enable, the relay agent will check the validity of the
packet's option 82 field. If the switch receives a packet that contains the option-82 field from
a DHCP client, the switch drops the packet because it is invalid. In packets received from
DHCP servers, the relay agent will drop invalid messages.
Disabled – When the field is toggled to Disabled, the relay agent will not check the validity
of the packet's option 82 field.
This field can be toggled between Replace, Drop, and Keep by using the pull-down menu. It
is used to set the Switches policy for handling packets when the DHCP Agent Information
Option 82 Check is set to Disabled. The default is Replace.
Replace – The option 82 field will be replaced if the option 82 field already exists in the
packet received from the DHCP client.
Drop – The packet will be dropped if the option 82 field already exists in the packet received
from the DHCP client.
Keep – The option 82 field will be retained if the option 82 field already exists in the packet
received from the DHCP client.
This function enables or disables the DHCP option 60 state. When option 60 is enabled, if
the packet does not have option 60, then the relay servers cannot be determined based on
option 60. The relay servers will be determined based on either option 60 or per IPIF
configured servers. If the relay servers are determined based on option 60, then the IPIF
configured servers will be ignored. If the relay servers are not determined by option 60 then
the IPIF configured servers will be used to determine the relay servers.
This function enables or disables the DHCP option 61 state. When option 61 is enabled, if
the packet does not have option 61, then the relay servers cannot be determined based on
option 61. The relay servers will be determined based on option 61 and the IPIF configured
servers will be ignored. If the relay servers are not determined either by option 60 or option
61, then IPIF configured servers will be used to determine the relay servers.
24