loopback interface is always alone in its network, what are the practical reasons to have IPv4 subnet prefix shorter than
/32 for these interfaces?
Moreover, why according to various standards IPv4 loopback address is any address from
127.0.0.0/8 network? Is not it a waste of about 16 million IP addresses?
127.0.0.0/8 - This block is assigned for use as the Internet host loopback address. A datagram sent by a higher level protocol to an address anywhere within this block should loop back inside the host. This is ordinarily implemented using only 127.0.0.1/32 for loopback, but no addresses within this block should ever appear on any network anywhere
Interestingly, there is no such kludge for IPv6 loopback addresses where
::1/128 used as a loopback.
The unicast address 0:0:0:0:0:0:0:1 is called the loopback address. It may be used by a node to send an IPv6 packet to itself. It must not be assigned to any physical interface. It is treated as having Link-Local scope, and may be thought of as the Link-Local unicast address of a virtual interface (typically called the "loopback interface") to an imaginary link that goes nowhere.