ECS4100 Series CLI Reference Guide-R07

Chapter 32 | DHCP Commands
DHCP Relay
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Command Mode
Global Configuration
Usage Guidelines
◆ Use this command when the Type and Length fields do not need to be relayed
as part of the CID and RID in the option 82 packets.
Example
Console(config)#ip dhcp relay information option encode no-subtype
Console(config)#
ip dhcp relay
information policy
This command sets the Information 82 forwarding policy of the switch’s
DHCP Relay service. Use the no form of the command to set the policy to
the default setting.
Syntax
ip dhcp relay information policy {drop | keep | replace}
no ip dhcp relay information policy
drop - Do not relay the DHCP request packet.
keep - Retain the original CID and RID in the option 82 information of the DHCP
request.
replace - Replace the CID and RID of the option 82 information with the relay
agent switch address information.
Default Setting
drop
Command Mode
Global Configuration
Usage Guidelines
◆ If set to drop, the original DHCP request packet flooded to the receiving VLAN
is received but not relayed to the DHCP server.
◆ When the replace policy is set, the DHCP request packet’s option 82 content
(RID and CID sub-option) is replaced with the relay agent switch’s address
information. The agent then unicasts the modified DHCP Request packet to the
DHCP server.
◆ When set to the keep option the DHCP request packet’s option 82 content is
unmodified. However the switch address information of the relay agent is
additionally added into the DHCP request packet. The agent finally unicasts the
modified DHCP Request packet including the original RID and CID to the DHCP
server.