H3C Technologies H3C S3100 Series Switches - Manual (Page 867)

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[SwitchA] interface GigabitEthernet 1/1/1
[SwitchA-GigabitEthernet1/1/1] port link-type trunk
[SwitchA-GigabitEthernet1/1/1] port trunk permit vlan 1001 2001
Configuring DHCP Option 82
# Enable DHCP snooping on Switch A, and configure GigabitEthernet 1/1/1 as a trusted port.
[Sysname] dhcp-snooping
[Sysname] interface GigabitEthernet 1/1/1
[Sysname-GigabitEthernet1/1/1] dhcp-snooping trust
[Sysname-GigabitEthernet1/1/1] quit
# Configure DHCP snooping to support option 82 on Switch A.
[Sysname] dhcp-snooping information enable
You can configure option 82 in other ways. For more information, see DHCP Configuration.
# Configure Switch A to add Option 82 carrying the original VLAN information to the DHCP requests.
[Sysname] dhcp-snooping information ignore-vlanmapping