Configuring Dhcp Snooping Entry Auto Backup - HPE FlexNetwork 10500 Series Configuration Manual

•
If the handling strategy is replace, configure a padding mode and padding format for Option 82.
If the handling strategy is keep or drop, you do not need to configure any padding mode or
padding format for Option 82. The settings do not take effect even if you configure them.
•
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.
•
DHCP snooping uses "outer VLAN tag.inner VLAN tag" to fill the VLAN ID field of sub-option 1
in verbose padding format if either of the following conditions exists:
DHCP snooping and QinQ work together.

DHCP snooping receives a DHCP packet with two VLAN tags.

For example, if the outer VLAN tag is 10 and the inner VLAN tag is 20, the VLAN ID field is
000a.0014. The hexadecimal digit a represents the outer VLAN tag 10, and the hexadecimal
digit 14 represents the inner VLAN tag 20.
•
The device name (sysname) must not include spaces if it is configured as the padding content
for sub-option 1. Otherwise, the DHCP snooping device will fail to add or replace Option 82.
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.
4. (Optional.) Configure a
handling strategy for DHCP
requests that contain
Option 82.
5. (Optional.) Configure the
padding mode and padding
format for the Circuit ID
sub-option.
6. (Optional.) Configure the
padding mode and padding
format for the Remote ID
sub-option.

Configuring DHCP snooping entry auto backup

The auto backup feature saves DHCP snooping entries to a backup file, and allows the DHCP
snooping device to download the entries from the backup file at device reboot. The entries on the
DHCP snooping device cannot survive a reboot. The auto backup helps the security features provide
services if these features (such as IP source guard) must use DHCP snooping entries for user
authentication.
NOTE:
If you disable DHCP snooping with the undo dhcp snooping enable command, the device deletes
all DHCP snooping entries, including those stored in the backup file.
To save DHCP snooping entries:
Command
system-view
interface interface-type interface-number
dhcp snooping information enable
dhcp snooping information strategy
{ drop | keep | replace }
dhcp snooping information circuit-id
{ [ vlan vlan-id ] string circuit-id | { normal
| verbose [ node-identifier { mac |
sysname | user-defined
node-identifier } ] } [ format { ascii |
hex } ] }
dhcp snooping information remote-id
{ normal [ format { ascii | hex } ] | [ vlan
vlan-id ] string remote-id | sysname }
96
Remarks
N/A
N/A
By default, DHCP snooping
does not support Option
82.
By default, the handling
strategy is replace.
By default, the padding
mode is normal and the
padding format is hex for
the Circuit ID sub-option.
By default, the padding
mode is normal and the
padding format is hex for
the Remote ID sub-option.