Re: IPv4 flag day

[sronan--- via NANOG <nanog () lists nanog org>]

If I have two upstream providers as an SMB, how do you propose I handle failover between the two of them without PAT?

> On Jun 19, 2026, at 1:57 PM, Gary Sparkes <gary () kisaracorporation com> wrote:
>
> Zero need for PAT. NPT means you *don't* have to PAT. Deploying PAT would be EXTRA steps.
>
> NPT means you're already 1:1 automatically, and you just open firewall ports for anything you need to inbound 
> external access. No additional configuration or setup needed.
>
> PAT immediately eliminates most of the SMB benefits. The only one you retain is the V4 allocation cost reduction .... 
> maybe.
>
> Any business internet will be giving you at least something like a /60 or /56, so as long as you subnet within that 
> size space there's zero reason to put in additional effort for PAT and all the downsides it brings along with it.
>
> -----Original Message-----
> From: sronan () ronan-online com <sronan () ronan-online com>
> Sent: Friday, June 19, 2026 1:48 PM
> To: nanog () lists nanog org
> Cc: Marco Moock <mm () dorfdsl de>; Gary Sparkes <gary () kisaracorporation com>; nanog () lists nanog org
> Subject: Re: IPv4 flag day
>
> The SMB use case is absolutely PAT. They aren’t going to 1:1 NAT all of their internal hosts to both providers 
> provided IPv6 space.
>
> > On Jun 19, 2026, at 1:16 PM, Gary Sparkes via NANOG <nanog () lists nanog org> wrote:
> >
> > The cybercafe? Faster and more reliable online gaming. Better VOIP services for communication.
> >
> > Gaming is something that *HUGELY* benefits from IPv6/NAT elimination.
> >
> > The SMB? More reliable/consistent SIP experience for their phones.
> > Cheaper network hardware for the same throughput. Reduced complexity.
> > Reduced costs (address space) if they're exposing anything externally
> > / need external inbound access. (All wins I've gained for my
> > customers, and yes, they're all either dual stack or v6 with edge
> > translation for some networks, but with reduced expenses overall and
> > more reliable/performant networks)
> >
> > Realistically, the only NAT that v6 should ever need is NPTv6 for the multihoming scenario (IEEE should just 
> > capitulate on that one, it just makes sense and it's not PAT that gives us all our problems in the first place), the 
> > rest just don't make sense and re-introduce complexity and issues that should be eliminated.
> >
> > IPv6 enabled me to rip out a LOT of NAT workaround code from systems I support, which greatly simplified a lot of 
> > things. Re-introducing PAT into V6 land as a common practice would, once again, require re-adding all those insane 
> > hacks and workarounds and decreasing reliability.
> >
> > We shouldn't need to solve those issues when we can eliminate them entirely.
> >
> > -----Original Message-----
> > From: Pedro Prado via NANOG <nanog () lists nanog org>
> > Sent: Friday, June 19, 2026 1:01 PM
> > To: North American Network Operators Group <nanog () lists nanog org>
> > Cc: Marco Moock <mm () dorfdsl de>; Pedro Prado <pedro.prado () gmail com>
> > Subject: Re: IPv4 flag day
> >
> > … which sounds right (not implementing something you don’t need).
> >
> > “Need” has a different interpretation for those inside a simple network and those interconnecting that network to 
> > everything else - a separation of values that Nat and even pat happens to handle pretty well IMHO, for the most part 
> > anyway, bar the well known issues.
> >
> > What value the granularity of addresses inside a SMB brings to the outside if the connectivity works without that? 
> > What does global-capable 128-bit addressing help a cyber cafe?
> >
> > I would hope that the research that goes into solving NAT/PAT issues
> > would trickle into improvements to the end to end upper protocols
> > which would eventually be unaware of how the network operates, similar
> > to how L2 is transparent today (bar MTU mismatches…)
> >
> > *Pedro Martins Prado*
> > pedro.prado () gmail com / +353 83 036 1875 (FaceTime & WhatsApp)
> >
> > > On Fri 19 Jun 2026 at 15:33, Marco Moock via NANOG
> > > <nanog () lists nanog org>
> > > wrote:
> > >
> > > > > Am 19.06.26 um 08:35 schrieb Arie Vayner:
> > > > > To move IPv6 to the next level of SMB/enterprise adoption we need to
> > > > > make it easier to consume by the average SMB - which means stop
> > > > > saying "NAT is evil" or "NAT is not supported in IPv6", and unblock relevant IETF work.
> > >
> > > There are devices for SMB that support stateful IPv6 NAT if they
> > > really need this. Although, my experience is that most of the network
> > > infrastructure in SMB environments is created one time and never
> > > touched unless necessary. They will also not implement IPv6 with NAT
> > > unless they really need it. Same applies to various other protocols.
> > >
> > > --
> > > Gruß
> > > Marco
> > >
> > > Junk-Mail bitte an trashcan () stinkedores dorfdsl de
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