RE: IPv4 flag day

[Gary Sparkes via NANOG <nanog () lists nanog org>]

I may have missed a few zeros there :D

I forget how large the reserved/non-issuable range is, that’s why I dropped out the 249 million part

From: Dorn Hetzel <dorn () hetzel org>
Sent: Sunday, June 21, 2026 8:34 PM
To: Gary Sparkes <gary () kisaracorporation com>
Cc: North American Network Operators Group <nanog () lists nanog org>; Arie Vayner <ariev () vayner net>
Subject: Re: IPv4 flag day

Don't you mean out of ~4,000,000,000 ? [4,294,967,296] ?

On Sun, Jun 21, 2026 at 6:33 PM Gary Sparkes <gary () kisaracorporation com<mailto:gary () kisaracorporation com>> 
wrote:
Honestly, I'm surprised this hasn't been proposed or being worked on yet, because at some point (probably in my 
lifetime) it may become necessary. Though, AFAIK, we're still sub 500,000 for issued ASN range, out of the 4,000,000 so 
possible.

But hobby ASNs and other usages are on the rise..... in some communities I see a lot of requests for help getting set 
up there, and most of those users are v6 only for obvious reasons....

-----Original Message-----
From: Dorn Hetzel via NANOG <nanog () lists nanog org<mailto:nanog () lists nanog org>>
Sent: Sunday, June 21, 2026 8:29 PM
To: North American Network Operators Group <nanog () lists nanog org<mailto:nanog () lists nanog org>>
Cc: Arie Vayner <ariev () vayner net<mailto:ariev () vayner net>>; Dorn Hetzel <dorn () hetzel org<mailto:dorn () 
hetzel org>>
Subject: Re: IPv4 flag day

Sure, have every hotdog cart run BGP, pretty soon we'll need 64 bit AS numbers :)


On Sun, Jun 21, 2026 at 6:29 PM Mike Hammett via NANOG < nanog () lists nanog org<mailto:nanog () lists nanog org>> 
wrote:

> Most pizza shops aren't going to be able to manage BGP.
>
>
>
> -----
> Mike Hammett
> Intelligent Computing Solutions
>
> Midwest Internet Exchange
>
> The Brothers WISP
>
>
> ----- Original Message -----
> From: "sronan--- via NANOG" <nanog () lists nanog org<mailto:nanog () lists nanog org>>
> To: nanog () lists nanog org<mailto:nanog () lists nanog org>
> Cc: "Arie Vayner" <ariev () vayner net<mailto:ariev () vayner net>>, nanog () lists nanog org<mailto:nanog () lists 
> nanog org>,
> sronan () ronan-online com<mailto:sronan () ronan-online com>
> Sent: Tuesday, June 16, 2026 4:24:25 PM
> Subject: Re: IPv4 flag day
>
> Sorry, but this is NOT a significant use case, and I wouldn’t buy
> service from any Internet provider who doesn’t support BGP.
>
> But frankly you could implement this exact same solution with IPv6
> without BGP anyway.
>
> Shane
>
> > On Jun 16, 2026, at 5:21 PM, Arie Vayner via NANOG <
> nanog () lists nanog org<mailto:nanog () lists nanog org>> wrote:
> > Hi everyone,
> >
> > There is also a significant set of use cases that currently work
> > better,
> or
> > at least more easily, with NAT.
> >
> > The most common example is small branch sites with dual ISP uplinks.
> There
> > are a vast number of these sites deployed using two small
> provider-assigned
> > (PA) NAT pools. This setup is widely understood, simple to
> > implement, and reliable.
> >
> > Moving these sites to IPv6 via BGP is often not feasible. Many ISP
> circuits
> > do not support BGP, and the teams operating these sites lack the
> > time to navigate that complexity. Furthermore, other IPv6
> > dual-homing options
> often
> > don't align with enterprise requirements or expected complexity (or
> really
> > simplicity) levels.
> >
> > In my view, this is a core reason why IPv6 adoption remains low in
> > the enterprise space: it requires fundamental paradigm shifts rather
> > than a simple protocol update.
> >
> > Thanks,
> > Arie
> >
> >
> > > On Tue, Jun 16, 2026, 8:10 AM Tom Beecher via NANOG <
> nanog () lists nanog org<mailto:nanog () lists nanog org>>
> > > wrote:
> > >
> > > > >
> > > > Is NAT still such a severe problem that we needed a different protocol?
> > > > Ask 1000 NANOG engineers, get 1000 different answers. In practice, no.
> > > > IPv4 still works.
> > >
> > >
> > > There are also plenty of well established things that NAT causes
> problems
> > > for, along with less than desirable protocol and standardization
> > > choices that have been made because of the existence of NAT.
> > >
> > > We've gotten really good at engineering ways to disguise these
> > > issues so users don't notice them. On one had that's good because
> > > user/application experiences are better, on the other hand it sucks
> > > because people think
> a
> > > non-visible problem isn't a problem anymore.
> > >
> > > On Tue, Jun 16, 2026 at 10:53 AM Brian Knight via NANOG <
> > > nanog () lists nanog org<mailto:nanog () lists nanog org>> wrote:
> > >
> > > > On 2026-06-16 01:33, Saku Ytti via NANOG wrote:
> > > > > Does anyone feel responsibility for the dual stack mess we've created?
> > > > > It wasn't here when we found the Internet, and we're going to
> > > > > leave it here after we leave, does not really jive with the whole
> > > > > leave campground cleaner than found it ethos.
> > > >
> > > > It was the most comprehensive solution for the NAT problem. But
> > > > NAT became the accepted way we connect to the Internet.
> > > >
> > > > World + dog knows how to connect to it, troubleshoot it, look at
> > > > NAT tables on their edge firewall or router.
> > > >
> > > > Is NAT still such a severe problem that we needed a different protocol?
> > > > Ask 1000 NANOG engineers, get 1000 different answers. In practice, no.
> > > > IPv4 still works.
> > > >
> > > > Economics are a slightly different story, but so far, IPv4 space
> > > > isn't prohibitively expensive.
> > > >
> > > > -Brian
> > > > _______________________________________________
> > > > NANOG mailing list
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