CLI Guide

Layer 3 Routing Commands 1488
Default Configuration
This is enabled by default for a DHCP relay agent.
Command Mode
Global Configuration mode, Virtual Router Configuration mode
User Guidelines
Enable DHCP Relay using the ip helper enable command. Interface
configuration takes precedence over global configuration. However if there is
no interface configuration then global configuration is followed.
This check is enabled by default. The administrator has to ensure that the
relay should be configured such that only it should insert option-82 fields and
no other device near the client has the facility to insert options.
When in Virtual Router Configuration mode, this command operates within
the context of the virtual router instance. When in Global Configuration
mode, the command operates on the global router instance.
Virtual Router Configuration mode is only available on the N3000-ON/N3100
switches.
Example
The following example enables relay information check globally:
console(config)#ip dhcp relay information check
ip dhcp relay information check-reply
Use the ip dhcp relay information check-reply command to enable DHCP
Relay to check that the relay agent information option in forwarded
BOOTREPLY messages is valid. If an invalid message is received, the relay
agent drops it. This information check will take effect, though enabled, only
when the relay agent interface is enabled to insert the suboptions.
Syntax
ip dhcp relay information check-reply [none]
no ip dhcp relay information check-reply
• none—(Optional) Disables the command function.