nanog mailing list archives

Re: 202401100645.AYC Re: IPv4 address block


From: Dave Taht <dave.taht () gmail com>
Date: Thu, 11 Jan 2024 12:37:43 -0500

On Thu, Jan 11, 2024 at 12:26 PM Tom Beecher <beecher () beecher cc> wrote:

Christopher-

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.


Citing Nick Hilliard from another reply, this is an incorrect statement.

on this point: prior to RIR depletion, the annual global run-rate on /8s
measured by IANA was ~13 per annum. So that suggests that 240/4 would
provide a little more than 1Y of consumption, assuming no demand
back-pressure, which seems an unlikely assumption.


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.


This has been discussed at great length at IETF. The consensus on the question has been consistent for many years 
now; doing work to free up 12-ish months of space doesn't make much sense

Thought that 12 month argument was purest BS in light of all the
events since 2011. We have been "out" of IPv4 space for many years
now, and there is a functioning market for IPv4 space that seems to be
serving the purpose. 240/4 is only marginally useful today, but useful
it is.

when IPv6 exists, along with plenty of transition/translation mechanisms. Unless someone is able to present new 
arguments that change the current consensus, it's not going to happen.

Instead, bigcos like google and amazon have been able to squat on
240/4 and take advantage of it for 5+ years now. I do kind of hope
others are using it up in the same ways they are.

Consensus, no. Just the few, like my team, that looked clearly at the
future internet's needs getting shouted down by those in power over
there. We cited many other arguments in favor of opening it up. There
are rumblings far outside the realm of the ietf.

I was once naive enough to consider the internet a vast, global,
shared, and beloved space with resources that needed to be conserved
and spread to and for all mankind. And while I still do feel that, our
existing bureaucracies and gatekeepers have seemingly infinite power
to say no, to even simple improvements to how the internet could work.

There is no reason whatsoever for 240/4 to remain "reserved". There
are plausible debates as to how it should be used, but rfc1918-style
only benefits the few.

On Thu, Jan 11, 2024 at 5:54 AM Christopher Hawker <chris () thesysadmin au> wrote:

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



-- 
40 years of net history, a couple songs:
https://www.youtube.com/watch?v=D9RGX6QFm5E
Dave Täht CSO, LibreQos


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