4-6Configuring DHCP SnoopingConfiguring DHCP SnoopingFollow these steps to configure DHCP snooping:To do… Use the command… RemarksEnter system view system-view —Enable DHCP snooping dhcp-snoopingRequiredBy default, the DHCP snoopingfunction is disabled.Enter Ethernet port view interface interface-typeinterface-number —Specify the current port as atrusted port dhcp-snooping trustRequiredBy default, after DHCP snooping isenabled, all ports of a switch areuntrusted ports.z If an S5600 Ethernet switch is enabled with DHCP snooping, the clients connected to it cannotdynamically obtain IP addresses through BOOTP.z 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 To enable DHCP snooping on an S5600 switch that belongs to an IRF fabric, do not configure theports connecting to the DHCP clients and DHCP server to belong to different units of the fabric;otherwise, the switch cannot record DHCP snooping entries although the clients can obtain IPaddresses.z You are not recommended to configure both the DHCP snooping and selective Q-in-Q function onthe switch, which may result in the DHCP snooping to function abnormally.Configuring DHCP Snooping to Support Option 82Enable DHCP snooping and specify trusted ports on the switch before configuring DHCP snooping tosupport Option 82.Complete the following tasks to configure the DHCP snooping to support Option 82:
