The `loopback' interface is a special type of interface that allows you to make connections to yourself. There are various reasons why you might want to do this. For example, you may wish to test some network software without interfering with anybody else on your network. By convention, the IP address `127.0.0.1' has been assigned specifically for loopback. No matter what machine you go to, if you open a telnet connection to 127.0.0.1 you will always reach the local host.
Configuring the loopback interface is simple, and it must be done (but note that this task is usually performed by the standard initialization scripts).
root# ifconfig lo 127.0.0.1 root# route add -host 127.0.0.1 lo
We'll talk more about the route command in the next section. Was this section helpful? Why not Donate $2.50?