Glossary: TCP/IP in Depth, Part 1
Host addresses (127.0.0.1, 0.0.0.0)
Also written: 127.0.0.1, 0.0.0.0, loopback address
Two special IPv4 addresses: 127.0.0.1 is the loopback address a machine uses to reach itself on its `lo` interface, and 0.0.0.0 means "no address", which `arping -D` uses as its sender address so that it changes no one's cache.
Where the book teaches it
Related terms
loopback interfaceduplicate address detectionunspecified address