H3C Technologies H3C S7500E Series Switches - Manual (Page 89)

8-8
DHCP Snooping Configuration Examples
DHCP Snooping Configuration Example
Network requirements
As shown in Figure 8-3 , Switch B is connected to a DHCP server through GigabitEthernet2/0/1, and to
two DHCP clients through GigabitEthernet2/0/2 and GigabitEthernet2/0/3. GigabitEthernet2/0/1
forwards DHCP server responses while the other two do not.
Switch B records clients’ IP-to-MAC address bindings in DHCP-REQUEST messages and DHCP-ACK
messages received from trusted ports.
Figure 8-3 Network diagram for DHCP snooping configuration
Configuration procedure
# Enable DHCP snooping.
<SwitchB> system-view
[SwitchB] dhcp-snooping
# Specify GigabitEthernet2/0/1 as trusted.
[SwitchB] interface GigabitEthernet2/0/1
[SwitchB-GigabitEthernet2/0/1] dhcp-snooping trust
[SwitchB-GigabitEthernet2/0/1] quit
DHCP Snooping Option 82 Support Configuration Example
Network requirements
z As shown in Figure 8-3 , enable DHCP snooping and Option 82 support on Switch B.
z Configure the handling strategy for DHCP requests containing Option 82 as replace.
z On GigabitEthernet2/0/2, configure the padding content for the circuit ID sub-option as
company001 and for the remote ID sub-option as device001.
z On GigabitEthernet2/0/3, configure the padding format as verbose, access node identifier as
sysname, and code type as ascii for Option 82.
z Switch B forwards DHCP requests to the DHCP server (Switch A) after replacing Option 82 in the
requests, so that the DHCP clients can obtain IP addresses.