H3C S5500-SI Series, Operation Manual

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You need to specify the ports connected to the valid DHCP servers as trusted to ensure that DHCP
clients can obtain valid IP addresses. The trusted port and the port connected to the DHCP client
must be in the same VLAN.
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You can specify Layer 2 Ethernet interfaces and Layer 2 aggregate interfaces as trusted ports. For
details about aggregate interfaces, refer to Link Aggregation Configuration in the Access Volume .
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If a Layer 2 Ethernet interface is added to an aggregation group, DHCP snooping configured on the
interface will not take effect. After the interface quits from the aggregation group, DHCP snooping
will be effective.
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Do not add an untrusted Layer 2 Ethernet interface to an aggregation group.
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Configuring both the DHCP snooping and selective QinQ function on the switch is not
recommended because it may result in malfunctioning of DHCP snooping.
Configuring DHCP Snooping to Support Option 82
Prerequisites
You need to enable the DHCP snooping function before configuring DHCP snooping to support Option
82.
Configuring DHCP Snooping to Support Option 82
Follow these steps to configure DHCP snooping to support Option 82:
To do… Use the command… Remarks
Enter system view system-view —
Enter interface view
interface interface-type
interface-number
—
Enable DHCP snooping to support
Option 82 dhcp-snooping
information enable
Required
Disabled by default.
Configure the handling strategy for
requesting messages containing Option
82 dhcp-snooping
information strategy
{ drop | keep | replace }
Optional
replace by default.