D-Link DGS-3700 Series Reference Manual page 491

DGS-3700 Series Layer 2 Managed Gigabit Ethernet Switch CLI Reference Guide
config dhcp_relay option_82 state
Purpose
Syntax
Description
Parameters
Restrictions
Example usage:
To configure DHCP relay option 82 state:
DGS-3700-12:5#config dhcp_relay option_82 state enable
Command: config dhcp_relay option_82 state enable
Success.
DGS-3700-12:5#
config dhcp_relay option_82 check
Purpose
Syntax
Description
Parameters
Restrictions
Example usage:
To configure DHCP relay option 82 check:
Used to configure the state of DHCP relay agent information option 82 of the switch.
config dhcp_relay option_82 state [enable | disable]
This command is used to configure the state of DHCP relay agent information option
82 of the switch.
enable − When this field is toggled to Enabled the relay agent will insert and remove
DHCP relay information (option 82 field) in messages between DHCP server and
client. When the relay agent receives the DHCP request, it adds the option 82
information, and the IP address of the relay agent (if the relay agent is configured),
to the packet. Once the option 82 information has been added to the packet it is
sent on to the DHCP server. When the DHCP server receives the packet, if the
server is capable of option 82, it can implement policies like restricting the number
of IP addresses that can be assigned to a single remote ID or circuit ID. Then the
DHCP server echoes the option 82 field in the DHCP reply. The DHCP server
unicasts the reply to the back to the relay agent if the request was relayed to the
server by the relay agent. The switch verifies that it originally inserted the option
82 data. Finally, the relay agent removes the option 82 field and forwards the
packet to the switch port that connects to the DHCP client that sent the DHCP
request.
disable − If the field is toggled to disable the relay agent will not insert and remove
DHCP relay information (option 82 field) in messages between DHCP servers and
clients, and the check and policy settings will have no effect.
Only Administrator and Operator-level users can issue this command.
Used to configure the checking mechanism of DHCP relay agent information option
82 of the switch.
config dhcp_relay option_82 check [enable | disable]
This command is used to configure the checking mechanism of DHCP/BOOTP relay
agent information option 82 of the switch.
enable – 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.
disable − When the field is toggled to disable, the relay agent will not check the
validity of the packet's option 82 field.
Only Administrator and Operator-level users can issue this command.
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