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Example: Configuring Option 82
Network configuration
As shown in
, the DHCP relay agent (Router A) replaces Option 82 in DHCP requests
before forwarding them to the DHCP server (Router B).
•
The Circuit ID sub-option is
company001
.
•
The Remote ID sub-option is
device001
.
To use Option 82, you must also enable the DHCP server to handle Option 82.
Procedure
# Specify IP addresses for the interfaces. (Details not shown.)
# Enable DHCP.
<RouterA> system-view
[RouterA] dhcp enable
# Enable the DHCP relay agent on GigabitEthernet 1/0/1.
[RouterA] interface gigabitethernet 1/0/1
[RouterA-GigabitEthernet1/0/1] dhcp select relay
# Specify the IP address of the DHCP server on the relay agent.
[RouterA-GigabitEthernet1/0/1] dhcp relay server-address 10.1.1.1
# Enable the DHCP relay agent to handle Option 82, and perform Option 82 related configuration.
[RouterA-GigabitEthernet1/0/1] dhcp relay information enable
[RouterA-GigabitEthernet1/0/1] dhcp relay information strategy replace
[RouterA-GigabitEthernet1/0/1] dhcp relay information circuit-id string company001
[RouterA-GigabitEthernet1/0/1] dhcp relay information remote-id string device001
Example: Configuring DHCP server selection
Network configuration
As shown in
, the DHCP client and the DHCP servers are in different subnets. DHCP server
1 and DHCP server 2 both have a DHCP address pool that contains IP addresses in subnet
22.22.22.0/24, but neither has DHCP enabled.
Configure the DHCP relay agent for the DHCP client to obtain an IP address in subnet 22.22.22.0/24
and other configuration parameters from a DHCP server. The DHCP relay agent is connected to the
DHCP client through GigabitEthernet 1/0/1, to DHCP server 1 through GigabitEthernet 1/0/2, and to
DHCP server 2 through GigabitEthernet 1/0/3.