Network requirements, Configuration procedure – H3C Technologies H3C S5120 Series Switches User Manual
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Because the DHCP relay agent and server are on different subnets, you need to configure a static route
or dynamic routing protocol to make them reachable to each other.
DHCP Relay Agent Option 82 Support Configuration Example
Network requirements
z
As shown in
, Enable Option 82 on the DHCP relay agent (Switch A).
z
Configure the handling strategy for DHCP requests containing Option 82 as replace.
z
Configure the padding content for the circuit ID sub-option as company001 and for the remote ID
sub-option as device001.
z
Switch A forwards DHCP requests to the DHCP server (Switch B) after replacing Option 82 in the
requests, so that the DHCP clients can obtain IP addresses.
Configuration procedure
# Specify IP addresses for the interfaces (omitted).
# Enable DHCP.
<SwitchA> system-view
[SwitchA] dhcp enable
# Add DHCP server 10.1.1.1 into DHCP server group 1.
[SwitchA] dhcp relay server-group 1 ip 10.1.1.1
# Enable the DHCP relay agent on VLAN-interface 1.
[SwitchA] interface vlan-interface 1
[SwitchA-Vlan-interface1] dhcp select relay
# Correlate VLAN-interface 1 to DHCP server group 1.
[SwitchA-Vlan-interface1] dhcp relay server-select 1
# Enable the DHCP relay agent to support Option 82, and perform Option 82-related configurations.
[SwitchA-Vlan-interface1] dhcp relay information enable
[SwitchA-Vlan-interface1] dhcp relay information strategy replace
[SwitchA-Vlan-interface1] dhcp relay information circuit-id string company001
[SwitchA-Vlan-interface1] dhcp relay information remote-id string device001
You need to perform corresponding configurations on the DHCP server to make the Option 82
configurations function normally.