16Configuring a loopback interfaceFollow these steps to configure a loopback interface:To do… Use the command… RemarksEnter system view system-view —Create a Loopback interface andenter Loopback interface viewinterface loopbackinterface-number —Set a description for the loopbackinterface description textOptionalBy default, the description of aninterface is the interface namefollowed by the "Interface" string.Shut down the loopback interface shutdownOptionalBy default, a loopback interface is uponce created.NOTE:You can configure settings such as IP addresses and IP routes on Loopback interfaces. For moreinformation, see theLayer 3—IP Services Configuration Guide andLayer 3—IP Routing ConfigurationGuide.Null interfaceIntroduction to null interfaceA null interface is a completely software-based logical interface, and is always up. However, you cannotuse it to forward data packets or configure an IP address or link layer protocol on it. With a null interfacespecified as the next hop of a static route to a specific network segment, any packets routed to thenetwork segment are dropped. The null interface provides a simpler way to filter packets than ACL. Youcan filter uninteresting traffic by transmitting it to a null interface instead of applying an ACL.For example, by executing the ip route-static 92.101.0.0 255.255.0.0 null 0 command (which configuresa static route leading to null interface 0), you can have all the packets destined to the network segment92.101.0.0/16 discarded.Only one null interface, interface Null 0, is supported on your switch. You cannot remove or create a nullinterface.Configuring null 0 interfaceFollow these steps to enter null interface view:To do… Use the command… RemarksEnter system view system-view —
