1558
Command Reference for AT-IX5-28GPX High Availability, High Power Video Surveillance PoE Switch
C613-50057-01 REV A
AlliedWare Plus™ Operating System - Version 5.4.5-0.x
D
YNAMIC
H
OST
C
ONFIGURATION
P
ROTOCOL
(DHCP) C
OMMANDS
IP
DHCP
-
RELAY
AGENT
-
OPTION
ip dhcp-relay agent-option
Overview
This command enables the DHCP Relay Agent to insert the DHCP Relay Agent
Information Option (Option 82) into the client-request packets that it relays to its
DHCP server. This allows the DHCP Relay Agent to pass on information to the
server about the network location of the client device. The DHCP Relay Agent strips
the DHCP Relay Agent Option 82 field out of the DHCP server’s response, so that
the DHCP client never sees this field.
When the DHCP Relay Agent appends its DHCP Relay Agent Option 82 data into
the packet, it first overwrites any pad options present; then if necessary, it increases
the packet length to accommodate the DHCP Relay Agent Option 82 data.
The
no
variant of this command stops the DHCP Relay Agent from appending the
Option 82 field onto DHCP requests before forwarding it to the server.
For DHCP Relay Agent and DHCP Relay Agent Option 82 introductory information,
see the
DHCP Feature Overview and Configuration Guide
.
NOTE
:
The DHCP-relay service might alter the content of the DHCP Relay Agent Option
82 field, if the commands
ip dhcp-relay agent-option
and
ip dhcp-relay information
policy
have been configured.
Syntax
ip dhcp-relay agent-option
no ip dhcp-relay agent-option
Default
DHCP Relay Agent Information Option (Option 82) insertion is disabled by default.
Mode
Interface Configuration for a VLAN interface.
Usage
Use this command to alter the DHCP Relay Agent Option 82 setting when your
device is the first hop for the DHCP client. To limit the maximum length of the
packet, use the
ip dhcp-relay max-message-length
command.
This command cannot be enabled if DHCP snooping is enabled on your device
(
service dhcp-snooping
command), and vice versa.
Examples
To make the DHCP Relay Agent listening on
vlan15
append the DHCP Relay
Agent Option 82 field, use the commands:
awplus#
configure terminal
awplus(config)#
interface vlan15
awplus(config-if)#
ip dhcp-relay agent-option
To stop the DHCP Relay Agent from appending the DHCP Relay Agent Option 82
field on
vlan15
, use the commands:
awplus#
configure terminal
awplus(config)#
interface vlan15
awplus(config-if)#
no ip dhcp-relay agent-option