4-5z You need to specify the ports connected to the valid DHCP servers as trusted to ensure that DHCPclients can obtain valid IP addresses. The trusted port and the port connected to the DHCP clientmust be in the same VLAN.z You can specify Layer 2 Ethernet interfaces and Layer 2 aggregate interfaces as trusted ports. Fordetails about aggregate interfaces, refer to Link Aggregation Configuration in the Access Volume.z If a Layer 2 Ethernet interface is added to an aggregation group, DHCP snooping configured on theinterface will not take effect. After the interface quits from the aggregation group, DHCP snoopingwill be effective.z Do not add an untrusted Layer 2 Ethernet interface to an aggregation group.z Configuring both the DHCP snooping and QinQ function on the switch is not recommendedbecause it may result in malfunctioning of DHCP snooping.Configuring DHCP Snooping to Support Option 82PrerequisitesYou need to enable the DHCP snooping function before configuring DHCP snooping to support Option82.Configuring DHCP Snooping to Support Option 82Follow these steps to configure DHCP snooping to support Option 82:To do… Use the command… RemarksEnter system view system-view —Enter interface view interface interface-typeinterface-number —Enable DHCP snooping to supportOption 82dhcp-snoopinginformation enableRequiredDisabled by default.Configure the handling strategy forrequesting messages containing Option82dhcp-snoopinginformation strategy{ drop | keep | replace }Optionalreplace by default.
