Especially given that it is now owned by Microsoft, which has been working on IPv6-only (at least on their corporate network) for almost a decade:
* https://blog.apnic.net/2017/01/19/ipv6-only-at-microsoft/
* https://www.arin.net/blog/2019/04/03/microsoft-works-toward-...
An excellent reason to move away from Github, I find.
One more thing to troubleshoot at 3 am, one more thing to teach to a disinterested tier 1 support team, one more thing for Chrome to be weird about, hundreds more rules to manage in a hostile load balancer, logging tools that don't understand ipv6.
Turned it off. End customer asked why the site got a little slower (CGN) and when we can turn ipv6 back on. As far as I know it's still on the backlog.
Things have definitely gotten better over time, though. The massive 90s style corporate networks will probably never transition, but smaller and more modern companies don't have that issue.
Apple mandating that apps are IPv6 compatible and various government legislation forcing companies to make their shitty middleware IPv6-compatible has improved things quite a bit so far. As uptake keeps rising, the need for technologies like STUN and TURN will slowly start decreasing, and as a result more and more people will end up in "untested" situations where not having IPv6 and falling back to legacy paths starts becoming a problem.
* https://engineering.fb.com/2017/01/17/production-engineering...
* https://www.internetsociety.org/blog/2014/09/facebook-launch...
IPv4 is actually the "leftover" stuff they have to deal with at the front end.
But they are an eye-balls heavy service, with a lot of mobile devices, which also tend to be IPv6-native.
"No". Not every human is psychologically prepared to do that. They want to acquiesce, to go along to get along, you need somebody to be firm. "No".
I have also found that an uncomfortable number of people do not consider it appropriate in any way shape or form. Even when it’s ultimately your call and no one else’s.
Folks don’t really like waves. They like looking at them from the shore, but freak out when it’s their turn to hang 10
Maybe we shouldn't even measure percentage adoption and instead just if github has finally adopted..
You'll need to update your DNS server to include those as AAAA records.
Do providers like NextDNS or RethinkDNS allow these sorts of overrides?
Best one I can think of is when bigger websites started actually dropping SSLv3 and TLSv1.0 (and later TLSv1.1) support, cutting off older browsers and operating systems. Google and Amazon still support TLSv1.0, but plenty of others (including Microsoft) have dropped 1.0 and 1.1. HN itself doesn't accept 1.1 anymore either.
Then there's browser support. Lots of websites - big and small - cut off support for Internet Explorer 6 when it was somewhere below 5% marketshare because the juice was no longer worth the squeeze. Of course, few of those actually fully cut off the ability to browse the (now broken) website fully but it's a datapoint suggesting trade-offs can and will be made for this sort of thing. Or to put it in the present: a significant amount of webapps don't support Firefox (3% market share) to the extent their product is completely unusable in it.
What they should have done is have their core network default to IPv6 with IPv4 an optional add-on for things like public IP addresses, CDN endpoints, edge routers, VPNs, etc...
Instead, their core networks are IPv4 only for the most part with IPv6 a distant afterthought.
That said, for their HTTP stack they use fastly (as far as I understand), which should make the shift moderately easier.
Nobody except the 140M subscribers on T-Mobile US's network:
* https://www.youtube.com/watch?v=d6oBCYHzrTA
But sure, be IPv4-only and add latency by forcing traffic through an extra translation box.
Most of the ipv4 world is now behind CGNAT, one user per ip is simply a wrong assumption.
/56 is often recommended as the minimum as for a (residential) customer. /48 is considered a "site" address prefix, and is the smallest allocation that can be advertised in BGP:
* https://blog.apnic.net/2020/06/01/why-is-a-48-the-recommende...
* https://www.infoblox.com/blog/ipv6-coe/a-48-for-every-site-a...
You get 65k subnets with it, which is what you get with 10/8.
If you're not an expert in this area it's worth a read - I certainly learned a few things!
This is a misconception. It is not the successor to IPv4, it is an alternative. Maybe the alternative is so good it will eventually make the older extinct, but it does not look like that
Try going IPv6-only by disabling IPv4 on your computer as a test and notice that almost nothing works except Google. End users shouldn't need to set up NAT64/6to4 tunneling. It should be ISPs doing that to prepare for the transition.
Also, notice how Android and iOS don't support turning off IPv4.
IMO with the right market conditions, IPv6 could spread really fast within 6-24 months. For example, most cloud providers are now charging for IPv4 addresses when IPv6 is free. Small changes like that push in the right direction.
This was at the behest of mobile network. E.g., T-Mobile US has 140M subscribers, and moved to IPv6-only many years ago:
The requirement is simply that the app does AAAA queries, and that it attempts to connect to them if they exist. It doesn't matter whether the server does v6 natively or if the ISP is covering for a v4-only server via backwards compatibility. (Native v6 will probably perform better, but any site that wants to give up that advantage is free to do so.)
v6 adoption is often an all or nothing, because if you run both stacks, you have to ensure they are consistent. While you can reasonably do it on your home LAN, doing it across an entire infrastructure is the worst.
Now you have to make sure all your subnets, routing, VLANs, firewall rules, etc work exactly the same in two protocols that have very little in common.
It is the equivalent of shipping two programs in different languages and maintaining exact feature parity between both at all times.
Which is what ISP are doing with 464XLAT deployments. IPv6-mostly networking and IPv4-as-a-service are things that are happening in real world right now.
Well, the curve has got to level-out at 100%.
That makes sense. The majority of IPv6 deployment is mobile.
The next wave of adoption requires ISPs start offering residential IPv6. Once this happens, router manufacturers will innovate around the IPv6 offering as a differentiator, making it easy to deploy by end-users. IPv6 wifi APs will then become ubiqutious and so forth across other services. Has to start with ISPs.
Yeah, I dont get why more ISPs don't offer carrier-grade NAT64 instead of the typical CGNAT
The only arguments I've ever heard against ipv6 that made any sense are that:
1: it's hard to remember addresses, which is mayyyyybe valid for homelab enthusiast types, but for medium scale and up you ought to have a service that hands out per-machine hostnames, so the v6 address becomes merely an implementation detail that you can more or less ignore unless you're grepping logs. I have this on my home network with a whopping 15 devices, and it's easy.
and 2: with v6 you can't rely on NAT as an ersatz firewall because suddenly your printer that used to be fat dumb and happy listening on 192.168.1.42 is now accidentally globally-routable and North Korean haxors are printing black and white Kim Il Sung propaganda in your home office and using up all your toner. And while this example was clearly in jest there's a nugget of truth that if your IOT devices don't have globally-routable addresses they're a bit harder to attack, even though NAT isn't a substitute for a proper firewall.
But both of these are really only valid for DIY homelab enthusiast types. I honestly have no idea why other people resist ipv6.
Data centers and most physical devices made the jump pretty early (I don't recall a time where the VPS providers I used didn't allow for IPv6 and every device I've used has allowed IPv6 in the last 2 decades besides some retro handhelds), but domestic ISPs have been lagging behind. Mobile networks are switching en masse because of them just running into internal limits of IPv4.
Domestic ISPs don't have that pressure; unlike mobile networks (where 1 connection needing an IP = 1 device), they have an extra layer in place (1 connection needing an IP = 1 router and intranet), which significantly reduces that pressure.
The lifespan of domestic ISP provided hardware is also completely unbound by anything resembling a security patch cycle, cost amortization or value depreciation. If an ISP supplies a device, unless it fundamentally breaks to a point where it quite literally doesn't work anymore (basically hardware failure), it's going to be in place forever. It took over 10 years to kill WEP in favor of WPA on consumer grade hardware. To support IPv6, domestic ISP providers need to do a mass product recall for all their ancient tech and they don't want to do that, because there's no real pressure to do it.
IPv6 exists concurrently with IPv4, so it's easier for ISPs to make anyone wanting to host things pay extra for an IPv4 address (externalizing an ever increasing cost on sysadmins as the IP space runs out of addresses) rather than upgrade the underlying tech. The internet default for user facing stuff is still IPv4, not IPv6.
If you want to force IPv6 adoption, major sites basically need to stop routing over IPv4. Let's say Google becomes inaccessible over IPv4 - I guarantee you that within a year, ISPs will suddenly see a much greater shift towards IPv6.
fd::1 is perfectly valid internal IPv6 address (along with fd::2 ... fd::n)
We've never done this before at this scale. Maybe this is just how long it takes?
I wouldn't be surprised if ISPs did all the management tasks through a 30-year-old homebrew pile of technical debt, with lots of things relying on basic assumptions like "every connection has exactly one ip address, which is 32 bits long".
Porting all of that to support ipv6 can easily be a multi-year project.
FWIW, as someone who has done exactly this in a megacorp (sloshing through homebrew technical debt with 32-bit assumptions baked in), the initial wave to get the most important systems working was measured in person-months. The long tail was a slog, of course, but it's not an all-or-nothing proposition.
The core team supported ipv6 for a long time, but its rather easy to do that part. The hard part is the customer edge and CPE and the stack to manage it, it may have a lifetime of 2 decades.
My home isp can't even do symmetrical gigabit, let alone ipv6...
Your wifi isn't symmetrical either.
For example, in IPv4 each host has one local net address, and the gateway uses NAT to let it speak with the Internet. Simple and clean.
In IPv6 each host has multiple global addresses. But if your global connection goes down, these addresses are supposed to be withdrawn. So your hosts can end up with _no_ addresses. ULA was invented to solve this, but the source selection rules are STILL being debated: https://www.ietf.org/archive/id/draft-ietf-6man-rfc6724-upda...
Then there's DHCP. With IPv4 the almost-universal DHCP serves as an easy way to do network inspection. With IPv6 there's literally _nothing_ similar. Stateful DHCPv6 is not supported on Android (because its engineers are hell-bent on preventing IPv6). And even when it's supported, the protocol doesn't require clients to identify themselves with a human-readable hostname.
Then there's IP fragmentation and PMTU that are a burning trash fire. Or the IPv6 extension headers. Or....
In short, there are VERY good reasons why IPv6 has been floundering.
I assume you mean "interface", not "host". Because it's absolutely not true that a host can only have one "local net address".
EDIT: a brief Google also confirms that a single interface isn't restricted to one address either: sudo ip address add <ip-address>/<prefix-length> dev <interface>
There is nothing about IPv6 that prevents ISPs from filtering ports for all customers. They almost all actively filter at least port 25, 139 and 445 regardless of the actual transport. So I'm not sure "blocking service hosting" is the actual goal here.
The problem seems to be that all of the large and wealthy nations of the world have made the necessary huge investments into IPv6 while many of their smaller neighbors and outlying countries and islands have struggled to get any appreciable deployment.
It should be a UN and IMF priority to get IPv6 networks deployed in the rest of the world so we can finally start thinking about a global cutover.
You can see southeast Asia is pretty green on the map of the post.
>it's in their best interest to ensure users can't host services without them.
They'll just keep blocking port 25. IPv6 won't change anything with regards to self hosting.
This is a tricky problem; providers don't have an easy way to correlate addresses or update policies pro-actively. And customers hate it when things suddenly break no matter how well you go about it.
[1] https://docs.github.com/en/enterprise-cloud@latest/organizat...
Unless your own organisation in the RR has the IP addresses assigned to you as Provider Independent resources, there just seems to be so many places where 'your' IP address could, albeit most likely accidentally, become not yours any more. And even then, just like domain names, stop renewing the registration and someone else will get them - I was that someone else recently...
[1] AS202858
Do you have a writeup of your setup somewhere or can you recommend some learning materials ?
Initial writeup based on IPv6: https://abarber.com/Setting-Up-ASN-IPv6-Routing-BIRD-Teltoni...
Have been having fun recently with an IPv4 block and Asynchronous routing, working on writing that up right now :)
IP filtering is a valuable factor for security. I know which IPs belong to my organisation and these can be a useful factor in allowing access.
I've written rules which say that access should only be allowed when the client has both password and MFA and comes from a known IP address. Why shouldn't I do that?
And there are systems which only support single-factor (password) authentication so I've configured IP filtering as a second factor. I'd love them to have more options but pragmatically this works.
There's value in restricting access and reducing ones attack surface, if only to reduce noice in monitoring.
The real question is, why are the crests so predictable? They're always on Saturdays; Sunday dips down a little below the crest, then Monday-Friday is down in the 45% range before the next Saturday jumps up to 50% again. (Fridays usually have a small rise, up to the 46-47% area).
My theory: mobile access rises on weekends. People are more often accessing Google services from their work computers Monday-Friday, but on Saturdays and Sundays most (not all) people are away from the office. Many of them will end up using smartphones rather than laptops for Internet access, for various reasons such as being outdoors. And since smartphones are nearly all using IPv6 these days, that means an uptick in IPv6 usage over the weekends.
Meanwhile corporate IT for business and education networks have less incentive to upgrade and typically lag behind in adoption in general.
- In a cafe wifi, I had partial connectivity. For some reason my wifi interface had an ipv6 address but no ipv4 address. As a result, some sites worked just fine but github.com (which is, incredibly, ipv4-only) didn't
- I created a ipv6-only hetzner server (because it's 2026) but ended up giving up and bought a ipv6 address because lack of ipv4 access caused too many headaches. Docker didn't work with default settings (I had to switch to host networking) and package managers fail or just hang when there's no route to the host. All of which is hard to debug and gets in your way
I wish hosting providers would give you a local routed ipv4 on ipv6 servers with a default NAT server. It is not that expensive I move 10Gbps "easily" and they could charge for that traffic.
You mean like AWS NatGW https://docs.aws.amazon.com/vpc/latest/userguide/vpc-nat-gat...
One such stat is here:
> adoption ranging from 71% among the top 100 to 32% in the long tail
https://commoncrawl.org/blog/ipv6-adoption-across-the-top-10...
Getting full coverage on AWS (/GCP/Azure) and few other key services (GitHub...) would be significant here imho.
Personally I think the design of IPv6 offers very little benefit; supposedly the Dept of Defense/Dept of War holds some 175 million IPv4 addresses, with other companies also holding large allocations - that should have been addressed 25-30 years ago as an administrative matter.
Does anybody know why that might be the case? What's the story of IPv6 deployment in France?
https://www.arcep.fr/la-regulation/grands-dossiers-internet-...
This gives operators a benefit of the vertical control for the whole ecosystem - from top to the bottom, including intricate parts of protocols and routing. And France, in contrast to other countries, does not suck here too - operators usually do a good job of meticulously maintaining their assets.
My personal impression is that this is the result of several cultural factors:
1. Ingrained respect of privacy, private property, and a peace of heart as they call it. As a practical result of that, you do not get spammy messages and ads from operators, banks, etc. You may get some, like 3 or 4 discounts/offers in a year. Compare that to other countries where you can easily get 10s/100s messages like that in a single day. In other countries, instead of upgrading the infrastructure, people are busy with spamming each other.
2. The harsh oceanic environment with hurricanes and storms fosters an appreciation for reliability and functionality. It also encourages a certain frugality: every cent matters. As a result, people tend to develop a strong sensitivity to situations where form is prioritized over function, and such approaches are quickly dismissed as impractical. This gives a certain internal freedom of being able to see through things to determine what they are in the long run and not what they appear to be on the surface.
3. French people don't like to overwork outside of working hours. So choosing something like IPv6 over IPv4 seems like a natural forward-looking investment for the future where you can have less maintenance burden and thus you can devote more time to enjoying other things in life.
Having all those things combined, it's not hard to see why France chose IPv6. It's a natural choice there and it's imposed by survival.
P.S. I've spent some time in France, but was born in another country.
It's been discussed on the apnic blog and at meetings heaps
Has something changed for the worse?
The story is that at the beginning I had IPv6, and a shared dynamic IPv4 behind a CGNAT, I asked for a rollback to a full duplex static IPv4 and for three years I had both a static personal IPv4 and an IPv6. A few weeks ago my router went down and since it went back up, I no longer have an IPv6 address. I called my ISP and they explained that I could either have IPv6 or a static IPv4, but not both, and that it's abnormal that I had both for so long… welp, it's sad to see IPv6 but getting it back is not worth abandoning my static IPv4 and going back to a dynamic shared IPv4.
https://www.ietf.org/archive/id/draft-thain-ipv8-00.html
Avoiding a dual-stack and making IPv4 a part of whatever superseeds it seems like the right choice to me.
IPv6 always seemed to me like throwing away all existing telephone numbers, just to support longer numbers.
This will probably help adoption. On the one hand it will generate more IPv6 traffic. On the other hand it will expose more developers to IPv6; which will expose them to any lack of support for IPv6 within their own products.
[1]: https://9to5mac.com/2025/08/14/apples-first-mac-with-5g-cell...
I have owned several Dell, HP and Lenovo Laptops in the past 15 years and I have never had a cellular modem.
When Apple makes a change like that it impacts a lot of customers because they have way fewer skews.
If you are single, have a phone contract, you would need some extra contract for a landline internet and wifi router because thats what a lot of people just do and now they can just add an esim and pay a little bit more.
Interesting that this sounds/feels a lot more right or useful than it did 5 years ago.
Personal web server running dual stack since early 2010s currently sees 18-20% v6 traffic. When split by type, counting only mobile users it reaches 30% at peak.
Bot/crawler traffic is ironically 100% v4.
Meanwhile: enabled h3 in september last year for the fun of it, instantly at >40% traffic by request count, passing 50% since the beginning of the year, h2 accounting almost all the remaining traffic and plain ssl/http requests <1% being just bots.
0/10 in Latvia with a local ISP, fun times.
I get the whole s-curve trend but if I squint at 2017, there is an inflection to slow the s-curve down.
Annoyingly, when setting up service with a fiber company in the last couple months, I explicitly asked about IPv6 connectivity and they said, "yes." Turns out "yes, but not in my region."
ABC, Always Be Closing.
amazon.com needs to get with the program. Still IPv4 only.
EDIT: Apparently it's 77% https://pulse.internetsociety.org/en/news/2026/01/china-hits...
The only way this will change is by increasing pressure on the resource of IPv4 networks. It was a few years ago that AWS broke the news to me that I'd be paying for IPv4 addresses but IPv6 would remain free. If enough services are forced, financially, to abandon an IPv4 presence, then their clients would be likewise forced to adopt IPv6 in order to retain connectivity.
But with the ubiquity of CGNAT and other technologies, it seems unrealistic that IPv4 will become so rare that it becomes prohibitively expensive, or must be widely abandoned. So that availability of the legacy protocol will inhibit widespread adoption and transitions to IPv6.
Just log onto AOL and type in keyword "WALMART" and save! It's friendly and safe.
But in reality at the moment there will probably always be at least one thing that only works with v4 a lot of the time.
Incentives are misaligned as well - it saves you money as the EC2 instance user, but the owner of the website you're trying to access has to support v4 anyway so they don't have a big incentive to change anything
As of now, there is no way to have a 100% internal ipv6. Many of the services, including CloudSQL or the connection between external and internal load balancers do not support ipv6, even when the external load balancer support ipv6 forwarding rules at the front end.
This means that careful internal ipv4 allocations still matter.
But the one interface that touches the internet can use v6: the one with a functionally infinite address space.
> IPv6 traffic crosses the 50% mark
Graph description:
> The graph shows the percentage of users that access Google over IPv6
There are reasons to expect both much more and much less traffic per user on IPv6 compared to IPv4...
The most difficult parts for a homelab in my experience is getting Docker to play nicely. All of the other stuff sort of just works these days. Even things like using DHCPv6 prefix delegation to obtain a routable subnet is almost trivial with how well-supported the protocol is with modern networking software.
https://ipv6.he.net/certification/ has instructions on how to get started.
- I don't want to have a permanent global unchanged ipv6 as in id of my traffic.
- IPv6 privacy extensions would change that but then I can not reach my two devices I do want to reach from outside anymore as my access router only supports DynDNS for its own address and no NAT in IPv6
So what would be the correct setup with IPv6 when using privacy extensions?
I don't see any benefit in allowing IPv6 traffic or using IPv6, but a couple of new problems coming up with it.
This approach prevents outbound connections from leaking the address needed to connect to your servers. On v4, it's likely that any outbound connection from your network gives the server the IP they need to do that.
Neither is IPv6
> To get, basically, the same effect as moving to IPv6
The only thing that IPv6 solves which is of interest to 99.99% of the users is having more adressable space. The rest of IPv6 features are either things that nobody asked for, or things which are genuinely worst compared to IPv4.
I consider the mere fact of enabling IPv6 an unacceptable security risk, as I would now have to make sure my IPv4 and IPv6 firewall stack are perfectly mirroring each other. That would be trivial with IPv4-with-more-bytes, it's a nightmare with IPv6.
All of IPv6 features are just direct effects of having more space and not. Basically IPv6 "features" is just getting rid of IPv4 workarounds.
Things have developed so much, a Internet2 is still going on I take it, however is more focussed on university research.
As ever a killer strength is something that draws people to a new technology, I imagine there's various demographics that benefit from use of ipv6.
Further I imagine that there are some levels of criticality which when reached are more self sustaining (dare I say it the network effect?).
I've been posting this graph over the years, and it really has slowed down hugely close to this 50%. This is a global ipv6 support, so some countries are racing ahead, others weirdly like Denmark have a stash of ipv4 addresses and seems content.
France and Germany are at about 80%, but there's the rest of the world of course.
It sounds to me like its a tool which is available to be used when needed and when no better workarounds exist, and it is slowly but surely being adopted as needed.
That seems to be a promising approach.
They use 464XLAT, basically NAT64/DNS64 with some extra cooperation on the OS’s part for backwards compatibility with apps that hard-code IPv4. You get only a v6 address, and your OS basically synthesizes an v4 network on your device in cooperation with their NAT64 router. But all the bytes going from your device through to their towers are ipv6. Talking to a v4-only website uses carrier-grade NAT64 when leaving the t-mobile network.
The author of the RFC is the author of the slides.
Is it because they have more carrier NAT?
In Denmark I can get cheap 1 / 1 Gbit/s fiber, but still no ipv6 :(
Does it mean we better put our chips on IPv8?
My company is ipv4 still, and some customers are having issues with ipv6 only connections.
Also we log the ip addresses, and that's only in ipv4.
Say if you have 10% of market share or x million monthly users you must support IPv6 in say 5 years. If not you are fined say 2% revenue per year until you do...
But I wouldn't be surpised if we start seeing self-hosted minecraft or factorio servers with ipv6 only.
There might be a child behind the NAT, thus IPv6 requirement.
Chris Siebenmann has written extensively on IPv6: https://utcc.utoronto.ca/~cks/space/?search=ipv6
Google has some weird way of asserting connectivity, and I suspect that when connectivity on one protocol is lost, it is impossible to maintain or establish connectivity through the other one (IPv6) even if it is available upstream.
I am rather infuriated with the status quo at this point, because it is impossible to disable IPv6 on my devices and it is also impossible for my ISP to disable IPv6 on my LAN or on the CPE router which they own and control.
Due to chronic WiFi issues I was eventually forced to place my ISP router into Bridge mode permanently, and I use a 3rd party Netgear which I own, and does not have the same WiFi issues, and where IPv6 is optional (and often fails, because its implementation is buggy and glitchy for no reason.)
I recently purchased a brand-new LaserJet printer, and since it needs nothing to do with the Internet or a WAN outside my home, I thought it'd be great to simply disable IPv4 and stop doing the DHCP dance.
Well it immediately fell off the net completely. I couldn't figure out how to expose its IPv6 address or contact its management interface.
Hypothetically, Bonjour and mDNS should make this a no-brainer. Hypothetically, disabling IPv4 shouldn't even prevent it from connecting to the Internet. But I was ultimately forced to factory-reset it.
IPv6-only LAN makes a lot of sense for most people, and perhaps reduces attack surface a little. If you have the means, I highly recommend setting it up!
google published the latest data only yesterday, hence the delay.
despite the smoothbrain naysayers:
https://circleid.com/posts/20190529_digging_into_ipv6_traffi...
finally, the end of the dark tunnel of NAT is in sight, and the internet will be free once more
Generally: I'm really surprised that Norway is just at 27%. I think I've been with 3 different residential ISPs the last 15 years, and all of them have done IPv6 perfectly well (two nits: I think one required a trivial opt-in, and my current ISP is just giving me /60 which isn't perfect).
Edit: Oops, sorry to my current ISP for shaming them. Some googling told me that one can get a /56 using DHCPv6-PD. I'll try that!
No change in trend during COVID years, interesting.
What's going on in Spain?
Was fun seeing IPv6 running for a few days without problems.
- IPv6 proponents are the only ones who know that NAT is not a firewall, and
- Everyone in the world would love IPv6 if they just didn't hate learning new things
> 1.1.1.1.1.1.1.1
[0] https://www.ietf.org/archive/id/draft-thain-ipv8-00.html
See the removed thread for details: https://news.ycombinator.com/item?id=47788857
IPv6 uses ip6.arpa and segments each little nybble into a subdomain!
https://en.wikipedia.org/wiki/Reverse_DNS_lookup#IPv6_revers...
This means there are always 32 octets to a reverse-IPv6 address, and there are no shortcuts or macros to overcome this! That means if you wish to assign a singular name that maps from a legitimate /64 Network ID, you must populate 64 bits worth of octets in a zone with this data. It is an absurd non-solution. This never should've been allowed to happen, but it will basically mean that ISPs abandon reverse DNS entirely when they migrate to IPv6 implementations.