62Because the DHCP relay agent and server are on different subnets, you need to configure static ordynamic routing to make them reachable to each other.DHCP server configuration is also required to guarantee the client-server communication through theDHCP relay agent. For DHCP server configuration information, see "DHCP server configurationexamples ."Figure 22 Network diagramConfiguration procedure# Specify IP addresses for the interfaces. (Details not shown.)# Enable DHCP. 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 10.1.1.1After the preceding configuration is complete, DHCP clients can obtain IP addresses and other networkparameters from the DHCP server through the DHCP relay agent. You can use the display dhcp relaystatistics command to view the statistics of DHCP packets forwarded by the DHCP relay agent. If youenable relay entry record on the DHCP relay agent with the dhcp relay client-information recordcommand, you can use the display dhcp relay client-information command to view relay entries.Option 82 configuration exampleNetwork requirementsAs shown in Figure 22, the DHCP relay agent (Router A) replaces Option 82 in DHCP requests beforeforwarding 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 BDHCP serverRouter ADHCP relay agentDHCP client DHCP clientDHCP clientDHCP clientEth1/210.1.1.2/24Eth1/110.10.1.1/24Eth1/110.1.1.1/24
