102 
Figure 37 Network diagram 
 
 
Configuration procedure 
# Enable DHCP snooping. 
<SwitchB> system-view 
[SwitchB] dhcp snooping enable 
# Configure GigabitEthernet 1/0/1 as a trusted port. 
[SwitchB] interface gigabitethernet 1/0/1 
[SwitchB-GigabitEthernet1/0/1] dhcp snooping trust 
[SwitchB-GigabitEthernet1/0/1] quit 
# Enable DHCP snooping to record clients' IP-to-MAC bindings on GigabitEthernet 1/0/2. 
[SwitchB] interface gigabitethernet 1/0/2 
[SwitchB-GigabitEthernet1/0/2] dhcp snooping binding record 
[SwitchB-GigabitEthernet1/0/2] 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 
Option 82 configuration example 
Network requirements 
As shown in Figure 38, enable DHCP snooping and configure Option 82 on Switch B as follows: 
•  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.