Dell Force10 MXL Blade - Loopback Interfaces; Null Interfaces

230 | Interfaces
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Loopback Interfaces
A Loopback interface is a virtual interface in which the software emulates an interface. Packets routed to it
are processed locally. Because this interface is not a physical interface, you can configure routing protocols
on 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 EXEC
mode.
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 more
information, refer to Access Control Lists (ACLs).
Null Interfaces
The null interface is a virtual interface. There is only one null interface. It is always up, but no traffic is
transmitted through this interface.
To enter INTERFACE mode of the null interface, use the following command in CONFIGURATION
mode:
The only configurable command in INTERFACE mode of null interface is the
ip unreachable command.
Command Syntax Command Mode Purpose
interface loopback number
CONFIGURATION Enter a number as the loopback interface.
Range: 0 to 16383.
Command Syntax Command Mode Purpose
interface null 0
CONFIGURATION Enter INTERFACE mode of null interface.