nanog mailing list archives

Re: 240/4 (Re: 44/8)


From: George Herbert <george.herbert () gmail com>
Date: Mon, 22 Jul 2019 21:02:07 -0700

Most importantly, if you're running out of 1918 space is a totally
different problem than running out of global routable space.

If you patch common OSes for 240/4 usability but a significant fraction of
say unpatched OSes, IOT, consumer routers, old random net cruft necessary
for infrastructure aren't patched... it's not actually globally routable.
At some point you can write off the few stragglers but... really, get IPv6
everywhere.

On Mon, Jul 22, 2019 at 8:50 PM Owen DeLong <owen () delong com> wrote:



On Jul 22, 2019, at 20:14 , Mikael Abrahamsson <swmike () swm pp se> wrote:

On Mon, 22 Jul 2019, Owen DeLong wrote:

     2.      It was decided that the effort to modify each and every IP
stack in order to facilitate use of this relatively small block (16 /8s
being evaluated against a global
             run rate at the time of roughly 2.5 /8s per month, mostly
to RIPE and APNIC) vs. putting that same effort into modifying each and
every IP stack to support
             IPv6 was an equation of very small benefit for slightly
smaller cost. (Less than 8 additional months of IPv4 free pool vs.
hopefully making IPv6 deployable
             before IPv4 ran out).

Well, people are working on making 240/4 usable in IP stacks:


https://raw.githubusercontent.com/dtaht/unicast-extensions/master/rfcs/draft-gilmore-taht-v4uniext.txt

There have been patches accepted into some BSDs and into Linux
tools/kernel and other operating systems to make 240/4 configurable and
working as unicast space.

I don't expect it to show up in DFZ anytime soon, but some people have
dilligently been working on removing any obstacles to using 240/4 in most
common operating systems.

For controlled environments, it's probably deployable today with some
caveats. I think it'd be fine as a compliment to RFC1918 space for some
internal networks.

--
Mikael Abrahamsson    email: swmike () swm pp se

I guess people can do whatever they want. I personally consider it to be a
sad sad waste of time that could be better spent deploying IPv6 to more
places.

Owen



-- 
-george william herbert
george.herbert () gmail com

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