Configuring Option 82 - HP 5920 Series Configuration Manual

To configure basic DHCP snooping:
Step
1. Enter system view.
2. Enable DHCP snooping.
3. Enter interface view.
4. Specify the port as a trusted
port.
5. Return to system view.
6. Enter interface view.
7. (Optional.) Enable recording
of DHCP snooping entries.

Configuring Option 82

Follow these guidelines when you configure Option 82:
If you configure Option 82 on an Ethernet interface that has been added to an aggregation group,
•
the settings do not take effect unless the interface is removed from the aggregation group.
To support Option 82, you must configure Option 82 on both the DHCP server and the DHCP
•
snooping device. For information about configuring Option 82 on the DHCP server, see
handling of Option
If the handling strategy is configured as replace, you must configure a padding format for Option
•
82. If the handling strategy is keep or drop, there is no need to configure any padding format.
If Option 82 contains the device name, the device name must contain no spaces. Otherwise, DHCP
•
snooping drops the message. You can use the sysname command to specify the device name. For
more information about this command, see Fundamentals Command Reference.
• If DHCP snooping and QinQ work together or DHCP snooping receives a DHCP packet with two
VLAN tags, and the verbose padding format is adopted for Option 82, DHCP snooping fills the
VLAN ID field of sub-option 1 with outer VLAN tag.inner VLAN tag. For example, if the outer VLAN
tag is 10 (a in hexadecimal) and the inner VLAN tag is 20 (14 in hexadecimal), the VLAN ID is
000a.0014.
To configure DHCP snooping to support Option 82:
Step
1. Enter system view.
2. Enter interface view.
3. Enable DHCP snooping to
support Option 82.
Command
system-view
dhcp snooping enable
interface interface-type
interface-number
dhcp snooping trust
quit
interface interface-type
interface-number
dhcp snooping binding record
82."
Command
system-view
interface interface-type interface-number
dhcp snooping information enable
64
Remarks
N/A
By default, DHCP snooping is
disabled.
This interface is connected to the
DHCP server.
By default, all ports are untrusted
ports after DHCP snooping is
enabled.
N/A
This interface is connected to the
DHCP client.
By default, after DHCP snooping is
enabled, recording of DHCP
snooping entries is disabled.
Remarks
N/A
N/A
By default, DHCP snooping
does not support Option
82.
"Enabling