ITS Certiport Networking Practice Test

Loopback addresses are used to reach the local machine itself, which is handy for testing software and the network stack without sending traffic onto any external network. For IPv4, the entire 127.0.0.0 to 127.255.255.255 range is reserved for loopback, commonly written as 127.0.0.0/8. The most familiar example is 127.0.0.1, which always refers to the local host. The other ranges shown serve different purposes: 192.168.0.0 to 192.168.255.255 is a private LAN range; 224.0.0.0 to 239.255.255.255 is used for multicast; and 10.0.0.0 to 10.255.255.255 is another private LAN range. So, the loopback addresses lie in the 127.x.x.x space.