H3C Technologies H3C S10500 Series Switches - Manual (Page 90)

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DHCP snooping configuration examples
DHCP snooping configuration example
Network requirements
As shown in Figure 35 , 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. GigabitEthernet 1/0/1
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 35 Network diagram for DHCP snooping configuration
Configuration procedure
# Enable DHCP snooping.
system-view
[SwitchB] dhcp-snooping
# Specify GigabitEthernet 1/0/1 as trusted.
[SwitchB] interface GigabitEthernet 1/0/1
[SwitchB-GigabitEthernet1/0/1] dhcp-snooping trust
[SwitchB-GigabitEthernet1/0/1] quit
DHCP snooping Option 82 support configuration example
Network requirements
• As shown in Figure 35 , enable DHCP snooping and Option 82 support on Switch B.
• Configure the handling strategy for DHCP requests containing 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 format as verbose, access node identifier as
sysname, and code type as ascii for Option 82.
• 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.