628 CHAPTER 59: DHCP S NOOPING CONFIGURATIONDHCP SnoopingConfigurationConfiguring DHCPSnoopingn ■ DHCP relay agent and DHCP snooping cannot be enabled at the same time. Ifyou have enabled DHCP relay agent on the device, you will fail to enable DHCPsnooping.■ The dhcp-snooping trust command and the dhcp-snooping command mustbe configured at the same time; otherwise DHCP packets may be dropped inactual networking.Configuring DHCPSnooping to SupportOption 82n Enable DHCP snooping and specify trusted ports on the switch before configuringDHCP snooping to support Option 82.Table 497 Configure the DHCP snooping functionOperation Command DescriptionEnter system view system-view -Enable the DHCP snoopingfunctiondhcp-snooping RequiredBy default, the DHCPsnooping function is disabledEnter Ethernet port view interface interface-typeinterface-number-Set the port connected to aDHCP server to a trusted portdhcp-snooping trust RequiredBy default, all ports of aswitch are untrusted portsTable 498 DHCP-snooping Option 82 support configuration tasksConfiguration task Description Related sectionEnable DHCP-snooping Option 82 support Required “EnablingDHCP-snoopingOption 82 support”on page 629Configure a handling policy for DHCP packetswith Option 82Optional “Configuring DHCPSnooping toSupport Option 82”on page 628“Configuring ahandling policy forDHCP packets withOption 82” on page629Configure the storage format of Option 82 Optional “Configuring DHCPSnooping toSupport Option 82”on page 628“Configuring thestorage format ofOption 82” on page630
