127.0.0.0 is in the 127.0.0.0/8 block which is assigned as the Internet host loopback address.
A datagram sent by a higher-level protocol to an addreess anywhere within this block
loops back inside the host. This is ordinarily implemented using only 127.0.0.1 for loopback.
Addresses within the entire 127.0.0.0/8 block do not legitimately appear on any network anywhere.
[ RFC1122, Section 126.96.36.199