H3C Technologies H3C WX3000E Series Wireless Switches - Manual (Page 73)

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To do… Use the command… Remarks
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
Optional
By default, the padding
content depends on the
padding format of Option 82.
Configure the
padding content
for the remote ID
sub-option
dhcp-snooping information [ vlan
vlan-id ] remote-id string
{ remote-id | sysname }
Optional
By default, the padding
content depends on the
padding format of Option 82.
NOTE:
•
You can only enable DHCP snooping to support Option 82 on Ethernet interfaces or aggregate
interfaces.
• If an Ethernet interface is added to an aggregation group, enabling DHCP snooping to support Option
82 on the interface will not take effect. After the interface quits the aggregation group, the configuration
will be effective.
• Option 82 support requires configuration on both the DHCP server and the device enabled with DHCP
snooping. See the chapter “DHCP server configuration” for DHCP server configuration of this kind.
• If the handling strategy of the DHCP-snooping-enabled device 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 the Option 82 is padded with the device name, the device name must contain no spaces. Otherwise,
the DHCP-snooping device will drop the message. You can use the sysname command to specify the
device name. For more information about this command, see the
Fundamentals Command Reference.
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 steps to configure DHCP snooping entries backup
To do… Use the command… Remarks
Enter system view system-view —
Specify the name of the file for
storing DHCP snooping entries dhcp-snooping binding
database filename filename
Required
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.