230 | Interfacesw w w . d e l l . c o m | s u p p o r t . d e l l . c o mLoopback InterfacesA Loopback interface is a virtual interface in which the software emulates an interface. Packets routed to itare processed locally. Because this interface is not a physical interface, you can configure routing protocolson this interface to provide protocol stability. You can place loopback interfaces in default Layer 3 mode.To configure a loopback interface, use the following command in CONFIGURATION mode:To view loopback interface configurations, use the show interface loopback number command in EXECmode.To delete a loopback interface, use the no interface loopback number command in CONFIGURATION mode.Many of the same commands found in the physical interface are found in loopback interfaces. For moreinformation, refer to Access Control Lists (ACLs).Null InterfacesThe null interface is a virtual interface. There is only one null interface. It is always up, but no traffic istransmitted through this interface.To enter INTERFACE mode of the null interface, use the following command in CONFIGURATIONmode:The only configurable command in INTERFACE mode of null interface is the ip unreachable command.Command Syntax Command Mode Purposeinterface loopback number CONFIGURATION Enter a number as the loopback interface.Range: 0 to 16383.Command Syntax Command Mode Purposeinterface null 0 CONFIGURATION Enter INTERFACE mode of null interface.
