User Manual
UMN:CLI
V5824G
301
If DHCP snooping is enabled in the system of V5824G, DHCP packets includes DHCP
option82 field by default.
To enable/disable the switch which is enabled by DHCP snooping to insert or remove
DHCP option82 field, use the following command.
Command
Mode
Description
ip dhcp snooping information
option
Global
Enables the switch to insert DHCP option 82 field in
forwarded DHCP packets to the DHCP server.
no
ip
dhcp
snooping
information option
Disables the switch not to insert DHCP option 82 field
in forwarded DHCP packets to the DHCP server
8.5.7.11
DHCP Snooping Option
DHCP snooping switch may receive DHCP messages (Discover/Request) with various
different options from clients, which cause DHCP server hard to manage
client’s
informtion in the perspective of data consistency. That
’s why this function is necessay.
The switch operating DHCP snooping can modify or attach an option field of the DHCP
messages (Discover/Request) with a defined snooping option and can forward them to
DHCP server. The snooping option can be applied on a port basis or on entire ports.
Before using this function, a global DHCP option format should be created. For details of
setting the DHCP option format, refer to the
To set a DHCP snooping option for a specifc port, use the following command.
Command
Mode
Description
ip dhcp snooping port
PORTS
opt-code
<1-254>
format
NAME
Global
Specifies a snooping option format on a port.
opt-code: DHCP option code
NAME: DHCP option format name
ip dhcp snooping port
PORTS
opt-code
<1-254>
policy
{
keep
|
replace
}
Configures a policy against DHCP option belonging to
a DHCP message (default: replace)
keep: forwards a DHCP message to DHCP server
without any modification.
replace: deletes the DHCP message
’s option and adds
the snooping option if both of them are same. However,
if they are different each other,
replace
option just
adds the snooping option.
no ip dhcp snooping port
PORTS opt-code
<1-254>
Removes the DHCP snooping option for a given port.
In case there is not a DHCP snooping option for a specific port, DHCP snooping switch
finds the snooping default option. If it exists, DHCP snooping switch sends a DHCP
server DHCP messages (Discover/Request) by replacing their options with the snooping
default option.
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