DGS-6604
ip dhcp relay information option
CLI Reference Guide
257
ip dhcp relay information option
Use this command to enable the insertion of the relay agent information option
(option 82). Use the no form of the command to disable this function.
ip dhcp relay information option
no ip dhcp relay information option
Syntax
None
Default
Disabled
Command Mode
Global configuration
Usage Guideline
Use this command to enable insertion of DHCP option 82.
When the DHCP 82 option is enabled, a DHCP packet received from a client will
have the option 82 field inserted before being relayed to the server. The DHCP
option 82 contains 2 sub-options: circuit ID and remote ID sub-options.
If the switch is standalone then the module field, within the circuit ID sub-option,
is always set to zero. The following describes the format of the Circuit and
Remote ID sub-option formats:
Circuit ID
suboption
format:
VLAN ID
- The incoming VLAN ID of DHCP client packet.
Module # -
For a standalone switch, Module # is always 0; For a stackable
switch, Module is Unit ID.
Port # -
The receiving port number of DHCP client packet, port number starts
from 1.
Remote ID sub
option format:
MAC address:
the switch's system MAC address.
Byte
1
2
3
4
5
6
7
8
Field
Sub-option
Type
Length
Circuit
IDType
Length
VLAN ID
Module # Port #
Value
1
6
0
4
X
X
X
Byte
1
2
3
4
5
6
7
8
9
10
Field
Sub-option
Type
Length
Remote
ID Type
Length
MAC Address
Value
2
8
0
6
M1
M2
M3
M4
M5
M6