H3C MSR 2600 Series, Configuration Manual

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Because the DHCP relay agent and server are on different subnets, you need to configure static or
dynamic routing to make them reachable to each other.
DHCP server configuration is also required to guarantee the client-server communication through the
DHCP relay agent. For DHCP server configuration information, see " DHCP server configuration
examples ."
Figure 22 Network diagram
Configuration procedure
# Specify IP addresses for the interfaces. (Details not shown.)
# Enable DHCP.
<RouterA> system-view
[RouterA] dhcp enable
# Enable the DHCP relay agent on Ethernet 1/1.
[RouterA] interface ethernet 1/1
[RouterA-Ethernet1/1] dhcp select relay
# Specify the IP address of the DHCP server on the relay agent.
[RouterA-Ethernet1/1] dhcp relay server-address 10.1.1.1
After the preceding configuration is complete, DHCP clients can obtain IP addresses and other network
parameters from the DHCP server through the DHCP relay agent. You can use the display dhcp relay
statistics command to view the statistics of DHCP packets forwarded by the DHCP relay agent. If you
enable relay entry record on the DHCP relay agent with the dhcp relay client-information record
command, you can use the display dhcp relay client-information command to view relay entries.
Option 82 configuration example
Network requirements
As shown in Figure 22 , 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.
Router B
DHCP server
Router A
DHCP relay agent
DHCP client DHCP client
DHCP client DHCP client
Eth1/2
10.1.1.2/24 Eth1/1
10.10.1.1/24
Eth1/1
10.1.1.1/24