DHCP
H3C Low-End Ethernet Switches Configuration Examples
Chapter 2 Configuration Examples
2-5
and the IRF Fabric are interconnected through the 172.16.2.4/30 network
segment.
z
Configure the address checking function on the DHCP relay agent so that only the
devices that are assigned legal IP addresses from the DHCP server are allowed to
access the external network.
z
Configure address entry update on the DHCP relay agent so that it updates the
address entries by sending requests to the DHCP server every one minute.
z
Enable DHCP snooping to support DHCP Option 82, adding local port information
to the Option 82 field in DHCP messages.
z
Enable the DHCP relay agent to support DHCP Option 82 so that the DHCP relay
agent keeps the original filed unchanged upon receiving DHCP messages
carrying Option 82.
z
Enable the DHCP server to support DHCP Option 82 so that it assigns the IP
addresses 192.168.10.2 through 192.168.10.25 to the DHCP clients connected to
Ethernet1/0/11 on the DHCP snooping switch and assigns 192.168.10.100
through 192.168.10.150 to the DHCP clients connected to Ethernet1/0/12 of the
DHCP snooping switch.
2.2.2 Network Diagram
IP network
SwitchA
(Master)
SwitchB
(Unit2)
SwitchC
(Unit3)
SwitchD
(Unit4)
VLAN-int 10
192.168.10.1
Eth1/0/1
Eth1/0/11
Eth1/0/12
Eth1/0/13
VLAN-int 17
172.16.2.4/30
VLAN-int 15
192.168.17.1
0010-5ce9-1dea
IRF Fabric
DHCP Relay
VLAN-int 25
192.168.19.1
Lab2
HQ
Office
Lab1
Lab DHCP Server
DHCP Snooping
Cisco Catalyst
3745
192.168.0.3
Figure 2-2
Network diagram for DHCP relay agent/snooping integrated configuration