161
Step Command
Remarks
3.
Enable DHCP snooping to
support Option 82.
dhcp snooping information enable
By default, DHCP snooping
does not support Option
82.
4.
(Optional.) Configure a
handling strategy for DHCP
requests that contain
Option 82.
dhcp snooping information strategy
{
drop
|
keep
|
replace
}
By default, the handling
strategy is
replace
.
5.
(Optional.) Configure the
padding mode and padding
format for the Circuit ID
sub-option.
dhcp snooping information
circuit-id
{ [
vlan vlan-id
]
string
circuit-id
| {
normal
|
verbose
[
node-identifier
{
mac
|
sysname
|
user-defined
node-identifier
} ] } [
format
{
ascii
|
hex
} ] }
By default, the padding
mode is
normal
and the
padding format is
hex
for
the Circuit ID sub-option.
6.
(Optional.) Configure the
padding mode and padding
format for the Remote ID
sub-option.
dhcp snooping information
remote-id
{
normal
[
format
{
ascii
|
hex
} ] | [
vlan
vlan-id
]
string
remote-id
|
sysname
}
By default, the padding
mode is
normal
and the
padding format is
hex
for
the Remote ID sub-option.
Configuring DHCP snooping entry auto backup
About 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.
Procedure
To save DHCP snooping entries:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Configure the DHCP
snooping device to back up
DHCP snooping entries to a
file.
dhcp snooping binding
database filename
{
filename
|
url url
[
username username
[
password
{
cipher
|
simple
}
string
] ] }
By default, the DHCP snooping
device does not back up DHCP
snooping entries.
With this command executed, the
DHCP snooping device backs up
DHCP snooping entries
immediately and runs auto backup.
This command automatically
creates the file if you specify a
non-existent file.
3.
(Optional.) Manually save
DHCP snooping entries to
the backup file.
dhcp snooping binding
database update now
N/A
