User's Manual

Configuration Guide of XGS-5240-Series
38-6
ip dhcp relay
information option
self-defined subscriber-id {vlan | port | id
(switch-
id (mac | hostname)|
remote-mac)| string WORD }
no ip dhcp relay information option
self-defined subscriber-id
Set creation method for option82, users
can define the parameters of circute-id
suboption by themselves
ip dhcp relay information option
self-defined subscriber-id format [ascii |
hex]
Set self-defined format of circuit-id for relay
option82.
7. Diagnose and maintain DHCP option 82
Command
Explanation
Admin mode
show ip dhcp relay information option
This command will display the state
information of the DHCP option 82 in the
system, including option82 enabling switch,
the interface retransmitting policy, the
circuit ID mode and the DHCP server
option82 enabling switch.
debug ip dhcp relay packet
This command is used to display the
information of data packets processing in
DHCP Relay Agent, including the “add” and
“peel” action of option 82.
38.3 DHCP option 82 Application Examples
Fig 3-2 A DHCP option 82 typical application example
In the above example, layer 2 switches Switch1 and Switch2 are both connected to layer
3 switch Switch3, Switch 3 will transmit the request message from DHCP client to DHCP serer
as DHCP Relay Agent. It will also transmit the reply message from the server to DHCP client to
Switch1
Switch2
DHCP Client PC1
DHCP Client PC2
DHCP Server
Vlan2:ethernet1/0/2
Vlan2:ethernet1/0/3
DHCP Relay Agent
Switch3
Vlan3