3Com MSR 50 Series Configuration Manual page 603

Network diagram
Figure 175 Network diagram for DHCP snooping configuration
Switch A
DHCP server
Eth 1 / 1
Switch B
DHCP snooping
Eth 1 / 3
Eth 1 / 2
DHCP client DHCP client
Configuration procedure
# Enable DHCP snooping.
<SwitchB> system-view
[SwitchB] dhcp-snooping
# Specify Ethernet1/1 as trusted.
[SwitchB] interface ethernet 1/1
[SwitchB-Ethernet1/1] dhcp-snooping trust
DHCP Snooping Configuration Example 603