Re: 202401100645.AYC Re: IPv4 address block

[Christopher Hawker <chris () thesysadmin au>]

There really is no reason for 240/4 to remain "reserved". I share Dave's
views, I would like to see 240/4 reclassified as unicast space and 2 x /8s
delegated to each RIR with the /8s for AFRINIC to be held until their
issues have been resolved.

Reclassifying this space, would add 10+ years onto the free pool for each
RIR. Looking at the APNIC free pool, I would estimate there is about 1/6th
of a /8 pool available for delegation, another 1/6th reserved.
Reclassification would see available pool volumes return to pre-2010 levels.

https://www.apnic.net/manage-ip/ipv4-exhaustion/

In the IETF draft that was co-authored by Dave as part of the IPv4 Unicast
Extensions Project, a very strong case was presented to convert this space.

https://www.ietf.org/archive/id/draft-schoen-intarea-unicast-240-00.html

Regards,
Christopher Hawker

On Thu, 11 Jan 2024 at 20:40, Dave Taht <dave.taht () gmail com> wrote:

> On Wed, Jan 10, 2024 at 11:06 AM Tom Beecher <beecher () beecher cc> wrote:
> > > There's a whole bunch of software out there that makes certain
> > > assumptions about allowable ranges. That is, they've been compiled with
> > > a header that defines ..
> >
> >
> > Of course correct. It really depends on the vendor / software / versions
> in an environment. A lot of vendors removed that years ago, because frankly
> a lot of large networks have been using 240/4 as pseudo RFC1918 for years.
> Others have worked with smaller vendors and open source projects to do the
> same.
> > It's consistently a topic in the debates about 240/4 reclassification.
>
> There's debates still? I gave up. After making 240/4 and 0/8 work
> across all of linux and BSD and all the daemons besides bird (which
> refused the patch , I took so much flack that I decided I would just
> work on other things. So much of that flack was BS - like if you kill
> the checks in the OS the world will end - that didn't happen. Linux
> has had these two address ranges just work for over 5 years now.
>
> 240/4 is intensely routable and actually used in routers along hops
> inside multiple networks today, but less so as a destination.
>
> I would really like, one day, to see it move from reserved to unicast
> status, officially. I would have loved it if 0/8 was used by a space
> RIR, behind CGNAT, for starters, but with a plan towards making it
> routable. I am not holding my breath.
>
> The principal accomplishment of the whole unicast extensions project
> was to save a nanosecond across all the servers in the world on every
> packet by killing the useless 0/8 check. That patch paid for itself
> the first weekend after that linux kernel deployed. It is the
> simplest, most elegant, and most controversial patch I have ever
> written.
>
> https://news.ycombinator.com/item?id=20430096
>
>
> > On Wed, Jan 10, 2024 at 10:45 AM Michael Butler <
> imb () protected-networks net> wrote:
> > > On 1/10/24 10:12, Tom Beecher wrote:
> > > > Karim-
> > > >
> > > > Please be cautious about this advice, and understand the full context.
> > > >
> > > > 240/4 is still classified as RESERVED space. While you would certainly
> > > > be able to use it on internal networks if your equipment supports it,
> > > > you cannot use it as publicly routable space. There have been many
> > > > proposals over the years to reclassify 240/4, but that has not
> happened,
> > > > and is unlikely to at any point in the foreseeable future.
> > >
> > > While you may be able to get packets from point A to B in a private
> > > setting, using them might also be .. a challenge.
> > >
> > > There's a whole bunch of software out there that makes certain
> > > assumptions about allowable ranges. That is, they've been compiled with
> > > a header that defines ..
> > >
> > > #define IN_BADCLASS(i)  (((in_addr_t)(i) & 0xf0000000) == 0xf0000000)
> > >
> > >         Michael
>
>
> --
> 40 years of net history, a couple songs:
> https://www.youtube.com/watch?v=D9RGX6QFm5E
> Dave Täht CSO, LibreQos