My points :

- I don't have a shortage of IPv4. Maybe my ISP or my VPN host do, I don't know. I have a roomy 10.0.0.0/8 to work with.

- Every host routable from anywhere on the Internet? No thanks. Maybe I've been irreparably corrupted by being behind NAT for too long but I like the idea of a gateway between my well kept garden and the jungle and my network topology being hidden.

- Stateless auto configuration. What ? No, no, I want my ducks neatly in a row, not wandering about. Again maybe my brain is rotten from years of DHCP usage but yes, I want stateful configuration and I want all devices on my network to automatically use my internal DNS server thank you very much.

- It's hard to remember IPv6 addresses. The prospect of reconfiguring all my router and firewall rules looks rather painful.

- My ISP gives me a /64, what am I supposed to do with that anyways?

- What happens if my ISP decides to change my prefix ? How do my routing rules need to change? I have no idea.

In short, so far, ignorance is bliss.

Obvious disclaimer: This is a sample size of 1, and an anecdote is not data, yada yada. I'm not involved in academia, and have no insight into the adoption of IPv6 in CompSci networking curricula on a broader level.

I'll get endless pushback for this, but the reality is that adoption isn't at 100%, it very closely needs to be, and there are still entire ISPs that only assign ipv4, to say nothing of routers people are buying and installing that don't have ipv6 enabled out of the box.

A much better solution here would have been an incredibly conservative "written on a napkin" change to ipv4 to expand the number of available address space. It still would have been difficult to adopt, but it would have the benefit of being a simple change to a system everyone already understands and on top of a stack that largely already exists.

I'm not proposing to abandon ipv6, but at this point I'm really not sure how we proceed here. The status quo is maintaining two separate competing protocols forever, which was not the ultimate intention.

Until somebody turned off the lights, that is. It is not much fun arguing with yourself in the dark.

I think that's what needed and needs to be done here. I will agree with the IPv4 advocates on one thing: IPv6 adoption has been slow in part because it doesn't work like IPv4 + kludges. That is the point. Clinging to IPv4 standard practices while you switch is just going to make you miserable.

In 2006, the hesitation to go to IPv6 made sense. Support was spotty. In 2026 it does not. IPv6 support is now more than adequate, and a clean cut will force the stragglers to get their asses in gear in a hurry ("fix your IPv6 support RFN or enjoy nobody using your product"). Change is painful, learning new stuff when you were getting by just fine on the old stuff is painful, I get it. But it will happen whether you like it or not. Why not just get it over with?

I finally made the switch to IPv6 last year, and I wouldn't go back.

The pain of change is real, but mercifully, it doesn't last. Within a year this debate will seem quaint.

Maybe not in the strict sense, but it kind of has.

In the enterprises I've worked in the past decade with IPv6 running, at least 75% of the Internet traffic is IPv6. In my discussions with other engineers managing large networks, they seem to be seeing more or less that same figure.

The problem is that virtually nobody knows IPv6. I regularly bring up IPv6 in engineers' circles and I'm often the only one who knows much about it. And so, I have doubts about it's long-term future, except for edge cases. I figure some clever scheme utilizing IPv4 and probably NAT will come around at some point.

Here’s a prediction. Linux on the desktop will have >50% penetration well before IPv6 does.

Future proofing it by jumping straight to 128 bits instead of 64. 64 would have been fine. Even with a load factor of 1:1000 by assigning semantics to ranges of IP addresses, 64 bit addressing is still enough addresses for 10 million devices per person.

If we become a galactic empire, we will have to replace the Web anyway because every interaction will have to be a standalone app or edge networking that doesn’t need to hear back from the central office for minutes, hours, days anyway. We could NAT every planet and go on forever.

This is the obvious and only key to this puzzle.

We tech nerds have this mad idea that everyone will want to spend time and money adapting to new standards because they're technically better in some abstract way, and so we do absolutely no work to create incentives for anyone to switch. Often, the new standard is not (yet) even functionally equivalent to the old one (e.g. Wayland), just to make doubly sure the switch will be as difficult and undesirable for end users as possible.

And when the absolutely inevitable consequences occur - stakeholders do not want to invest in switching to or developing for new standards that give them zero incentive to do so - there's a silly finger pointing game, as though everyone was supposed to switch, and they've failed to do so. Which is, of course, absurd. People don't owe us compliance.

Do not expect to be able to successfully shift behaviour unless you give people incentives - reasons they would want to switch, not just reasons you want them to switch.

I had mentioned some of that in my post: https://ssg.dev/ipv6-for-the-remotely-interested-af214dd06aa...

It should have been ipv4 with extra optional bits, so you could have the same rules and everything for both stacks.

I turn it off because it's a risk having one of either stacks malconfigured.

IPv6 should've been a superset of IPv4, as in addresses are shared, not that you have a separate IPv4 and IPv6 address for your server.

Because, it's not going away: You can talk all you want about how IPv6 should have been a more straightforward expansion of the address size, but this is all in the rear-view mirror at this point. IPv6 is going to be with us forever, you may as well get used to it. It's already everywhere in 5G deployments, ISP's like Comcast use it for 100% of their out-of-band management, China is making huge progress moving to it as part of their 5-year plan, India is progressing nicely in their transition, the list goes on. We're already way too far along in the transition to abandon it in favor of something else.

But it's not going to happen any quicker than we've seen, either: There's no urgency (no "must-have" use case) except for what organizations are imposing on themselves. Yeah, IPv4 addresses are more expensive, but you don't really need many of them as a business (you can get by with a small handful of public ones, and just using L7 load balancers and SNI for everything) nor as an ISP (CGNAT can get you a long way.)

So we have a situation where things are migrating very slowly, mainly only in places where it makes sense (mobile deployments, home ISP's where the users don't actually administer the network), and generally mostly for new deployments. This is a recipe for IPv4 to be around for a very, very long time. We're used to technology moving at breakneck pace, but that's only the case for the higher-level stuff. The core infrastructure like the internet protocol is likely the textbook example of slow-and-steady, and a case where it's actually not crazy to think of centuries-long timeframes for things.

[0] Barring any unforeseen black-swan events like a world war destroying all technology and having to rebuild from scratch or something. Or a competent international agreement to aggressively migrate to it (I don't know which is more likely.)

> "In fact, IPv4's continued viability is largely because IPv6 absorbed that growth pressure elsewhere – particularly in mobile, broadband, and cloud environments," he added. "In that sense, IPv6 succeeded where it was needed most, and must be regarded as a success."

Apparently it turns out IPv6 wasn't for me any way!

At what point will we be allowed to say IPv6 hasn't failed? When the IPv4 internet finally switches off for good? It feels like no achievement is high enough for those who don't like IPv6 to change their minds. I would've thought making up 50% of internet traffic and 50% of end devices being on IPv6-only networks would be good Schelling points, but evidently they're not!

I agree it's not a failure, but after 3 decades it's still frustratingly annoying to use at times.

Does anyone have any success stories from the server side handling a situation like this? Looks like cloudflare switched to some kind of custom dynamic rate limiting based on like addresses, but it's unrealistic to expect everyone to be able to do such a thing.

Now, I can simply restart my router (or cycle airplane mode on mobile) and get a new IPv4 that probably was used by bazillion people before me, or even along with me, and get a new account. So Google has to be very careful here, with IP-linked bans in order to not just ban the whole load of unconnected people just because they used the same IPv4 as me.

With IPv6, they could just ban my entire family and any guests that might have connected to my WiFi, forever.

I like the limitations of IPv4, thank you.

Only half joking, some UK MPs might actually consider this a reasonable thing considering how many ipv6s there are.

In my case, I administrate a small server at home, where I self host many services that are made available to myself, friends and families, over the internet.

In that context, IPv6, is SADLY (please note that I have NOTHING against IPv6), a limitation, even a nightmare to use.

Some programs do not handle IPv6 at all. Game servers for instance, do not support it, the one that I think about is: Arma 3. But there are many others

In 2025 (and 2026 too?), 4G (5G?) operators do not all route over IPv6 -> which means that if your domain only has a AAAA record, some people using 4G will not be able to access ANY of your services. This issue forced me to beg my ISP to obtain an IPv4 "fullstack" as they call it.

Without that IPv4 you have to go through some kind of tunneling (like Cloudflare) -> and guess what? Cloudflare sometimes crashes (it happened super recently remember?) and in that situation -> ALL your services accessible through the tunnel are "down" for your users. Plus, it is EXTREMELY unsatisfying to rely on an external private-owned service for a selfhosting project.

In almost ALL context IPv6 is seen as optional, additional, additional configuration and is NEVER the default. NEVER. Which means: more configuration, possibly more struggle.

Next year that chart will finally cross 50%. It was a mere 30% in 2030. Developing country mobile phone networks will continue to push it higher.

All we need to do is start having rich governments mandate IPv6, and also mandate IPv4 downtime as a punishment for those that don't comply / chaos engineering for the system as a whole. Then we can quickly finish the job.

Land lines internet have been IPv6 for more than a decade.

While developping custom IPv6 internet software I am not blocked by NAT anymore, real p2p fiesta, everything works as intended.

The real challenge now is IPv6 with fixed mobile internet address (not random as it is is now, it should be device uniq). That to replace for good the phone numbers (the challenge of international roaming... which is already done for phone numbers). The idea would be to avoid a third party centralized internet account->ipv6 mapping.

The only wrinkle I ran into is that apparently ISPs are still reluctant to give out static IPv6 prefixes to residential customers. So you still need some kind of DDNS setup, which is lame.

But here's a more thought-out design:

- register a well-known IPv6 prefix with 20 bits reserved for AS number

- so we'd have ${well_known_prefix}:${AS_number}:${customer_prefix}:${end_entity} (not necessarily that format for display, but just for the purpose of getting the idea across here)

- have DNS servers return AAAA RRs with the AS number filled in

- DNS servers should either have the correct AS numbers filled in their zones, or possibly could subscribe to the RPKI and use the RPKI for mapping ${well_known_prefix}:${all_zero_AS}:${customer_prefix}:* to AS numbers, then fill them in (this would require live signing if using DNSSEC, which is f-i-n-e fine)

- if there are multiple AS numbers for a $customer_prefix, then return multiple AAAA RRs, or if EDNS0 indicates client support for it, one AAAA RR and N RRs of a new type that carry only the AS numbers

- update core routers to route these prefixes based on the AS number in the address

- update edge routers to replace the sender's AS number in its address if its address is below the $well_known_prefix -- this takes care of the return path

- update internal routers to use only the $customer_prefix and the $end_entity for routing for this $well_known_prefix

- end entities should ignore the AS number when receiving packets, thus allowing multi-homing (i.e., let source and destination IPv6 addresses match ${well_known_prefix}:*:${customer_prefix}:${end_entity} for socket 5-tuples)

- for backwards compatibility end entities should map these addresses back to whatever the application used in its calls to bind() and connect() (i.e., if the app found an AAAA with the AS number filled in and used it for connect(), but the ${customer_prefix} is multi-homed, then accept packets from all those homes) (apps should make sure to use TLS / QUIC for security, naturally)

- when an end-entity sees a change in AS number for a peer's address matching a socket 5-tuple then update the peer's AS number / address in the 5-tuple -- this allows for migration and better path finding

I think something like this could be deployed with relatively little effort.

(This is of course an incomplete and poorly thought out proposal, you don't need to dogpile me about that.)

I have met zero network engineers who wanted to put IP version 6 in their network. It causes all sorts of problems and presents all sorts of security risks without much benefit other than the obvious one. In the data center, NAT is a feature, not a bug.

Instead, they provision IPv6-enabled load balancers and pass traffic back to load bearing servers using ipv4 instead.

It's a classic example of "this is the next best thing everyone should use it" which achieves some adoption but it's not really the next best thing. It's not the be all end all it purports to be.

We should just admit to ourselves that we need one kind of ip stack in some situations and another in another.

Also it acts as a nice security perimeter. If all IoT devices in a home were exposed to internet, It would be absolute mess.

[1] - https://nlnetlabs.nl/downloads/publications/ipv6/v6rootglue....

Ofcourse legacy compatibility trumps all, along with the ubiquity of NATs and roaming and we're now just in the sunk-cost phase, being left saddled with a horribly bloated protocol (128-bit addresses was a marketing choice; not engineering) that solves no problems.

Internet engineers pre-2000 had some idealistic, heavly mathematically proven ideas that still seem revolutionary today. Due to human nature, not everything got through, but IPv6 is the best of what we have and creating another standard would be XKCD 927.

Under every IPv6 discussion people all of sudden have the urge to manually assign numbers, need to remember their cousin's phone IP and MAC address, forget firewalls exists, argue that ISP fiddling with TCP+UDP selling it as "Internet" is a good thing or that "sender" field on the envelope is a huge privacy issue.

> but IPv6 is better

It doesn't solve any life-changing problem.

IPv4 really only had 3 problems that anybody cared about:

1. Address space size;

2. Roaming; and

3. Reliable connectionless delivery; and

4. The problems created by the at most once delivery under TCP when what we really needed was at least once delivery in many, many cases.

Even the address space size problem is less of an issue than originally predicted because of improvements in NAT, up to and including cgNAT for cellular network providers (which also somewhat addressed (2) in a limited way).

Interestingly, some of the larger companies have networks simply too large for the 10.0.0.0/8 address space.

By "roaming" I mean maintaining a consistent connection while moving between networks.

(4) has kinda fallen on QUIC (now HTTP3) but this should really be core TCP/IP Layer 3.

You could also say that TCP congestion control is pretty outdated. It's not surprising. It was designed at a time before megabit (let alone gigabit) networks. And, more importantly, latency kills throughput. Some efforts have been made on this, such as Google's BBR [2], but other problems remain like MTU windows being too small for modern networks.

So what did IPv6 do? It only solved one problem, address space, and it did it in a way that kinda created new problems. First, the address space is too large (128 bits) and the last 64 bits are kinda reserved for the job that a 16 port used to do. And why was that? Originally, it was intended that the lower 64 bits were derived from a 48 bit MAC address (as used by Ethernet and later Wifi) but they realized this was a huge privacy problem so it never happened.

[1]: https://en.wikipedia.org/wiki/Second-system_effect

[2]: https://github.com/google/bbr

[2]: https://community.cisco.com/t5/networking-knowledge-base/und...

(a while ago I needed to contact support to get an IPv6 allocation at home, but that was a very quick interaction at the time)

While IPv6 doesn’t make establishing a P2P connection trivial (there are still firewalls to contend with) - it does simplify things dramatically. And as someone who is behind CGNAT, I am very grateful for the existence of IPv6.

[1] https://tailscale.com/blog/how-nat-traversal-works

And it is consumer devices (and IoT devices) which are the most numerous and also the most price sensitive, and this is where IPv4 is disappearing first.

I'm reminded of way back in the day when they wanted charge per user or per device in households.

I don't have anything against it per-say but I have no reason to use it either.

We just take the sheer amount of engineering that went to designing network protocols for granted.

[1] - https://www.google.com/intl/en/ipv6/statistics.html

Having said that I still want to have a router with routing rules and firewalls and a network range I can divide into separate protected networks but in reality your home ISP will most likely give you a router with a /64 address.

Breaks NAT privacy and the extensions do not do enough.

Top down pushed solution NOBODY WANTS.

Even if ipv6 was just as simple , the cost of rebuild , retest and re-deploy is enough of a barrier against migration

And it will not be, as long as

* (S|D)NAT are not first class citizen in IPV6 Standards and Implementation * there's no mapping of the IPv4 Adresspace into the v6 space, so people can reroute stuff which is needed.

because only then, we can a) migrate b) rebuild the same structures.

because people will never let go of something.

https://github.com/systemd/systemd/issues/16322

However, extrapolation suggests the 50% mark might have finally been crossed around year end.

0. https://www.google.com/intl/en/ipv6/statistics.html

Apple TV, Amazon Echo/eero, Google Nest are all Thread/Matter hub.

Ikea just started to selling cheap Thread devices. It will soon be mainstream to have IPv6 devices in your home network.

If I need to connect to my home Fedora machine from work, a simple "ssh fed.nono.io" works just fine — I don't need to activate my Wireguard VPN; I don't need to worry about address space collisions.

Even more than IPv4, not knowing enough about IPv6 can introduce a lot of unintended issue, consequence and even security gaps in your assumptions.

Maybe there was an IPv7 or 8 that will be more palatable.

I don't think there is any way it could have been.

Vs. real meat is in the comments on the Register's site.

I've been using IPv6 via Starlink for months now and it was a big ho-hum when I deployed it. It just works.

We all thought the internet would become decentralized and that everyone should have an IP and a funky website. But instead social media took over, big tech and a few big discussion sites where we all must fit in a digital life and watch ads and share our data to become a good product for all the others to consume.

I'm sure someone will fuck this up for us, but IPv6 should at least in theory enable us to be rid of NAT. Anyone who has ever done NAT traversal for peer discovery is having wet dreams about that future!

I have ONE static external IPv4 for my network.

I can handle everything I want with it. And block everything I dont want my network to be.

So I just disable IPv6 on router (Mikrotik).

Not interested, not wanting it. That is it. If someone needs it, feel free to use it. I wont support double configurations on my router because of it.

Legacy IPv4 would be trivial to support via NAT, and we wouldn't have to deal with address shortages either globally or locally. I'm sure every sysadmin/cloud person dealt with having to arrange subnets by hand, or the fallout when you just ran out of addresses and had to tear down multiple layers of routing just to make more address space.

Computers default to 64 bit integers, I don't see why this couldn't be done on the network.

Then it's failure is by design. I should not want to multiplex/bridge different versions of the network-layer protocol; and certainly not to avoid using the new protocol because the old one seems more usable and approachable.

but if you need maximum AI slop, that's everywhere

It's sort of interesting dude says Security and Plug-and-Play weren't available in v6 since SLAAC and IPSec are mandatory parts of the spec. But sure, AH and ESP options are never as simple as they should have been and it's not impossible to pick options for your organization that don't match what a remote organization supports. I still prefer it to the crap-shoot that is TLS ChangeCipherSpec. (Though 1.2 and 1.3 aren't as bad as the old days.)

Contrary to the narrative about your parents not being able to cope with anything technical, my mom was able to configure her mac to speak to the family VPN with no problem. Of course, my mom taught me code in Lisp in the 70s and used a Sun 3/60 as her daily driver in the late 80s, so maybe that's not the best example.

Sure. V6 didn't take over the world, but neither did SNA or IPX/SPX, though I would argue v6 is MUCH more common these days than either IBM or Novell protocols. V6 is used in the corner of the internet by people who want to use V6. Maybe there's a "those who know don't tell, those who tell don't know" narrative here. I've sort of stopped evangelizing. If the main thing you worry about is watching Netflix, MMORPGing and commenting on Reddit, you don't need V6 and it does require a different bit of knowledge than setting up V4.

#OldManYellsAtClouds

I used to be a network admin, so I know how to configure networks. IPv6 zealots accuse me of incorrect config, doing it wrong, etc. Maybe that is the case, but if I, a sophisticated user, can't get it working well, what chance does a non-technical person have?

My assumption is they just deal with the issues and chalk it up to "technology sucks". But I know better. I've experienced the internet when it works, and I know when it isn't working right.

I think IPv6 is better in theory, and I look forward to the day that it is in practice. But today is not that day.

And I work with IP networks all the time, as well as run LAN Parties as a business. You'd think I would have encountered at least ONE reason to give a crap about IPv6 by now.

But nope, not one reason.

IPv4 gets work done. IPv6 is just a topic that we can wax poetic about, but nothing else.

Half. The. Internet.

What a failure. /s

to protect your privacy

A large number of my devices and websites I visit use IPv6. Its success has highlighted the fact that I don't want it. Just today I disabled IPv6 on my router because I suspect it as a vector for tracking.

IPv6 offers nothing of value to the user. It might as well be shelved forever.

ISPs do not want this.

That is all you need to know about why you can’t have IPv6.