4-7
Displaying and Maintaining DHCP Snooping
To do…
Use the command…
Remarks
Display DHCP snooping entries
display dhcp-snooping
[
ip
ip-address
]
Display Option 82 configuration information
on the DHCP snooping device
display dhcp-snooping
information
{
all
|
interface
interface-type interface-number
}
Display DHCP packet statistics on the
DHCP snooping device
display dhcp-snooping packet
statistics
Display information about trusted ports
display dhcp-snooping trust
Available in any
view
Clear DHCP snooping entries
reset dhcp-snooping
{
all
|
ip
ip-address
}
Clear DHCP packet statistics on the DHCP
snooping device
reset dhcp-snooping packet
statistics
Available in
user view
DHCP Snooping Configuration Examples
DHCP Snooping Configuration Example
Network requirements
z
As shown in
Figure 4-3
, Switch B is connected to a DHCP server through GigabitEthernet 1/0/1,
and to two DHCP clients through GigabitEthernet 1/0/2 and GigabitEthernet 1/0/3.
z
GigabitEthernet 1/0/1 forwards DHCP server responses while the other two do not.
z
Switch B records clients’ IP-to-MAC address bindings in DHCP-REQUEST messages and
DHCP-ACK messages received from trusted ports.
Figure 4-3
Network diagram for DHCP snooping configuration
GE1/0/1
DHCP server
Switch B
DHCP snooping
GE1/0/2
GE1/0/3
DHCP client
DHCP client
Configuration procedure
# Enable DHCP snooping.
<SwitchB> system-view
[SwitchB] dhcp-snooping
# Specify GigabitEthernet 1/0/1 as trusted.
[SwitchB] interface gigabitethernet 1/0/1
