Configuring dhcp snooping entries backup – H3C Technologies H3C S12500 Series Switches User Manual
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Step Command
Remarks
6.
Configure user-defined
Option 82.
•
Configure the padding content for the
circuit ID sub-option:
dhcp-snooping information [ vlan
vlan-id ] circuit-id string circuit-id
•
Configure the padding content for the
remote ID sub-option:
dhcp-snooping information [ vlan
vlan-id ] remote-id string { remote-id |
sysname }
•
Configure the padding content for the
sub-option 9:
dhcp-snooping information [ vlan
vlan-id ] sub-option sub-option-code
[ string user-string&<1-8> ]
Optional.
By default:
•
The padding content for the
circuit ID sub-option depends on
the padding format of Option
82.
•
The padding content for the
remote ID sub-option depends
on the padding format of
Option 82.
•
Sub-option 9 is not padded.
Configuring DHCP snooping entries backup
DHCP snooping entries cannot survive a reboot. If the DHCP snooping device is rebooted, security
modules (such as IP source guard) that use DHCP snooping entries to authenticate users will reject
requests from clients until new entries are learned.
The DHCP snooping entries backup feature enables you to store DHCP snooping entries in a file. When
the DHCP snooping device reboots, it reads DHCP snooping entries from this file.
Follow these guidelines when you configure DHCP snooping entries backup:
•
After DHCP snooping is disabled with the undo dhcp-snooping command, the switch will delete all
DHCP snooping entries, including those stored in the file.
•
If you specify a subdirectory in the name of the file that stores DHCP snooping entries, make sure
the subdirectory is available on each MPU. Otherwise, the system will fail to create the file on MPUs
without the specified subdirectory. To solve this problem, cancel the current configuration and
specify a new subdirectory in the file name.
To configure DHCP snooping entries backup:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Specify the name of the file for
storing DHCP snooping
entries.
dhcp-snooping binding
database filename filename
Not specified by default.
DHCP snooping entries are stored
immediately after this command is
used and then updated at the
interval set by the dhcp-snooping
binding database update interval
command.