Using the Loopback Interface for Debugging.

Using the Loopback Interface for Debugging.

The localhost is the standard host name given to the address of the loopback network interface. The IP address of the localhost is:

• IPv4: 127.0.0.1,
• IPv6: [::1].

Packets that are destined for the localhost address, are routed back internally by the IP layer of the Network Component. Such packets are never delivered to any network interface controller.

Using the loopback interface is useful for testing the software, since it bypasses the local network interface hardware. Connecting to locally hosted network services using loopback addresses puts less of a load on network resources.

You can also use the local host IP address to communicate between different applications using sockets on the same system, for example between a FTP server and FTP client. The FTP client connects to the FTP server and manages files on the FTP server using the localhost address. Of course, the files are manipulated locally on the same system. No IP packets actually appear on any of the hardware interfaces.

Note

• The loopback interface is created in the Network Component internally and does not require a physical network connection.