3Com 4210 9-Port - Configuring DHCP Snooping to Support Option 82

3-6
After DHCP snooping is enabled, all ports of a Switch 4210 are untrusted ports. You need to specify the
port of the Switch 4210 connected to the valid DHCP server as trusted to ensure that DHCP clients can
obtain valid IP addresses. The trusted port and the port connected to the DHCP clients must be in the
same VLAN.
Configuring DHCP Snooping to Support Option 82
Enable DHCP snooping and specify trusted ports on the switch before configuring DHCP snooping to
support Option 82.
Table 3-1 DHCP-snooping Option 82 support configuration task list
Task Remarks
Enable DHCP-snooping Option 82 support Required
Follow these steps to configure a handling policy for DHCP packets with
Option 82
Optional
Configure the storage format of Option 82 Optional
Configure the circuit ID sub-option Optional
Configure the remote ID sub-option Optional
Configure the padding format for Option 82 Optional
Enable DHCP-snooping Option 82 support
Follow these steps to enable DHCP-snooping Option 82 support:
Operation Command Description
Enter system view
system-view
—
Enable DHCP-snooping Option
82 support
dhcp-snooping information
enable
Required
By default, DHCP snooping
Option 82 support is disabled.
Configure a handling policy for DHCP packets with Option 82
Follow these steps to configure a handling policy for DHCP packets with Option 82:
Operation Command Description
Enter system view
system-view
Optional