3Com Switch 8800 Advanced Software V5 Configuration Guide

Displaying and Maintaining DHCP Relay Agent Configuration 741
Prerequisites
You need to complete the following tasks before configuring the DHCP relay
agent to support Option 82.
■ Enabling DHCP
■ Enabling the DHCP relay agent on the specified interface
■ Correlating a DHCP server group with relay agent interfaces
Configuring the DHCP relay agent to support Option 82
Use the following commands for this configuration:
n
■ To support Option 82, it is required to perform related configuration on both
the DHCP server and relay agent. Refer to
“Enabling the DHCP Server to
Support Option 82” on page 731 for DHCP server configuration of this kind.
■ If the handling strategy of the DHCP relay agent is configured as replace, you
need to configure a padding format for Option 82. If the handling strategy is
keep or drop, you need not configure any padding format.
■ If sub-option 1 (node identifier) of Option 82 is padded with the device name
(sysname) of a node, the device name must contain no spaces. Otherwise, the
DHCP relay agent will drop the message.
Displaying and
Maintaining DHCP
Relay Agent
Configuration
no Option 82 - Normal Forward the message after adding the
Option 82 padded in normal format.
- Verbose Forward the message after adding the
Option 82 padded in verbose format.
To do... Use the command... Remarks
Enter system view system-view -
Enter VLAN interface
view
interface vlan-interface
interface-number
-
Enable the relay agent
to support Option 82
dhcp relay information enable Required
Disabled by default
Configure the handling
strategy for requesting
messages containing
Option 82
dhcp relay information strategy
{ drop | keep | replace }
Optional
replace by default
Configure the padding
format for Option 82
dhcp relay information format {
normal | verbose [
node-identifier { mac | sysname |
user-defined node-identifier } ] }
Optional
normal by default
If a client’s request
message has...
Handling
strategy
Padding
format The DHCP relay agent will...
To do... Use the command... Remarks
Display information about DHCP
server groups correlated to a
specified or all interfaces
display dhcp relay { interface
interface-type interface-number
| all }
Available in any view
Display information about
bindings of DHCP relay agents
display dhcp relay security [
dynamic | static | ip-address ]
Available in any view