Figure 32 Network diagram
Procedure
# Assign GigabitEthernet 1/0/1, GigabitEthernet 1/0/2, and GigabitEthernet 1/0/3 to VLAN 100.
<SwitchB> system-view
[SwitchB] vlan 100
[SwitchB-vlan100] port gigabitethernet 1/0/1 to gigabitethernet 1/0/3
[SwitchB-vlan100] quit
# Enable DHCP snooping for VLAN 100.
[SwitchB] dhcp snooping enable vlan 100
# Configure GigabitEthernet 1/0/1 as DHCP snooping trusted port.
[SwitchB] vlan 100
[SwitchB-vlan100] dhcp snooping trust gigabitethernet 1/0/1
# Enable recording clients' IP-to-MAC bindings in VLAN 100.
[SwitchB-vlan100] dhcp snooping binding record
[SwitchB-vlan100] quit
Verifying the configuration
# Verify that the DHCP client can obtain an IP address and other configuration parameters only from
the authorized DHCP server. (Details not shown.)
# Display the DHCP snooping entry recorded for the client.
[SwitchB] display dhcp snooping binding
Example: Configuring DHCP snooping support for Option 82
Network configuration
As shown in
•
Configure the handling strategy for DHCP requests that contain Option 82 as replace .
•
On GigabitEthernet 1/0/2, configure the padding content for the Circuit ID sub-option as
company001 and for the Remote ID sub-option as device001 .
•
On GigabitEthernet 1/0/3, configure the padding mode for the Circuit ID sub-option as
verbose , access node identifier as sysname , and padding format as ascii . Configure the
padding content for the Remote ID sub-option as device001 .
Figure
33, enable DHCP snooping and configure Option 82 on Switch B as follows:
95