User's Manual

31-3
1. Enabling the DHCP option 82 of the Relay Agent.
Command
Explanation
Global mode
ip dhcp relay information option
no ip dhcp relay information option
Set this command to enable the option 82
function of the switch Relay Agent. The “no
ip dhcp relay information option” is used to
disable the option 82 function of the switch
Relay Agent.
2. Configure the DHCP option 82 attributes of the interface
Command
Explanation
Interface configuration mode
ip dhcp relay information policy {drop |
keep | replace}
no ip dhcp relay information policy
This command is used to set the
retransmitting policy of the system for the
received DHCP request message which
contains option 82. The drop mode means
that if the message has option82, then the
system will drop it without processing; keep
mode means that the system will keep the
original option 82 segment in the message,
and forward it to the server to process;
replace mode means that the system will
replace the option 82 segment in the existing
message with its own option 82, and forward
the message to the server to process. The
“no ip dhcp relay information policy” will set
the retransmitting policy of the option 82
DCHP message as “replace”.
ip dhcp relay information option
subscriber-id {standard | <circuit-id>}
no ip dhcp relay information option
subscriber-id
This command is used to set the format of
option 82 sub-
option1(Circuit ID option)
added to the DHCP request messages from
inte
rface, standard means the standard
VLAN name and physical port name format,
like”Vlan2+Ethernet1/12”,<circuit-
id> is the
circuit-id contents of option 82 specified by
users, which is a string no longer than
64characters. The”
no ip dhcp relay
information option subscriber-id”
command will set the format of added option
82 sub-
option1 (Circuit ID option) as
standard format.