2-7DHCP Snooping Configuration ExamplesDHCP Snooping Configuration ExampleNetwork requirementsAs shown in Figure 2-3, Switch A is connected to a DHCP server through GigabitEthernet1/0/1, and totwo DHCP clients through GigabitEthernet1/0/2 and GigabitEthernet1/0/3. GigabitEthernet1/0/1forwards DHCP server responses while the other two do not.Switch A records clients’ IP-to-MAC address bindings in DHCP-REQUEST messages and DHCP-ACKmessages received from trusted ports.Figure 2-3 Network diagram for DHCP snooping configurationConfiguration procedure# Enable DHCP snooping. system-view[SwitchA] dhcp-snooping# Specify GigabitEthernet1/0/1 as trusted.[SwitchA] interface GigabitEthernet 1/0/1[SwitchA-GigabitEthernet1/0/1] dhcp-snooping trust[SwitchA-GigabitEthernet1/0/1] quitDHCP Snooping Option 82 Support Configuration ExampleNetwork requirementsz As shown in Figure 2-3, enable DHCP snooping and Option 82 support on Switch A.z Configure the handling strategy for DHCP requests containing Option 82 as replace.z On GigabitEthernet1/0/2, configure the padding content for the circuit ID sub-option ascompany001 and for the remote ID sub-option as device001.z On GigabitEthernet1/0/3, configure the padding format as verbose, access node identifier assysname, and code type as ascii for Option 82.z Switch A forwards DHCP requests to the DHCP server after replacing Option 82 in the requests,so that the DHCP clients can obtain IP addresses.
