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

Owen DeLong owen at
Wed Mar 9 03:35:30 UTC 2022

One thing is for certain… If folks had put 0.10 as much effort into deploying IPv6 as has been put into arguing about whether or not ~17 /8s worth of IPv4 makes a meaningful difference to the internet as a whole, IPv4 would long since have become irrelevant as it must eventually be.


> On Mar 8, 2022, at 18:35, Seth David Schoen <schoen at> wrote:
> 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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