SIDN: impact of any routable 127.0.0.0/8 series is huge
SIDN points out that the proposal to keep only the 127.0.0.0/16 range of IP addresses for loopback is not a ‘minor change’, as stated by the authors of the internet draft. The proposal should free up millions of IPv4 addresses.
SIDN points to the consequences if most of the 127.0.0.0/8 series is released, as participants of the IPv4 Unicast Extensions / Cleanup Project want. “It will require adjustments in the network stacks of all hosts, in all network hardware and in all network software. The biggest problems will be that the addresses released will not be usable in practice due to poor routing/acceptance, and software that was previously only accessible locally can suddenly be approached from the outside.” The foundation also mentions the criticism that it is easier to implement IPv6.
In an Internet Draft, authors propose to keep only the 127.0.0.0/16 series for loopback. The ranges from 127.1.0.0 through 127.255.0.0 would then become available as regular unicast addresses. Thanks to the move, which the authors call a ‘minor change’, 16 million IPv4 addresses will become available. This should bring some relief, as there is an increasing shortage of IPv4 addresses.
Until now, the 127.0.0.0/8 block has been entirely reserved for loopback applications. The addresses can be used internally within systems for routing, with 127.0.0.1 as localhost, but cannot be accessed from outside. If the members of the IPv4 Unicast Extensions / Cleanup Project get their way, that will change. Incidentally, this is just one of the proposals of the project participants: the participants want to free up a total of 419 million IPv4 addresses in various ways.
According to SIDN, the Internet Draft makes clear how great the need is with regard to the shortage of IPv4 addresses. According to IPv4 Market Group, the amount paid for an IPv4 address increased significantly in the second half of 2021. Tech giants such as Microsoft, Google and Oracle would buy up IPv4 addresses. Amazon would have about 100 million IPv4 addresses, which represented a value of 2.5 billion dollars due to the price increase. Amazon paid $108 million in 2020 for 4 million IPv4 addresses of radio amateurs.