CC: s to Non List Members (was Re: 202203080924.AYC Re: 202203071610.AYC Re: Making Use of 240/4 NetBlock)

Seth David Schoen schoen at
Wed Mar 9 02:35:18 UTC 2022

John R. Levine writes:

> This still doesn't mean that screwing around with 240/4 or, an even worse
> 127/8 minus 127/24, is a good idea.

I hope you'll be slightly mollified to learn that it's actually 127/8
minus 127/16.

That's the most challenging one, but we've still seen something of a
lack of people getting in touch to point out concrete problems.

One person did get in touch to describe an unofficial use of, apparently,
all of 127/8 as private address space in a VPN product.  If people let
us know about more, we can investigate workarounds or possible changes
to our proposals.

We previously thought that the reference NTP implementation was using
all of 127/8 to identify hardware clock drivers.  But it turns out it
doesn't actually connect to these.

If anyone reading this knows of something that uses a loopback address
outside of 127/16 for an application, or something that can't be updated
and would be harmed if the rest of the network stopped treating this as
loopback, we'd be glad to hear about it.

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