My first IPv6 implementation was in 2010-2011 (memory a but fuzzy). Carriers supporting BGP over IPv6 were few, websites over IPv6 were also scarce.
Fast forward 15 years snd the situation has improved quite dramatically.
IPv6 has some quirks that make it harder to digest.
- link local gateway address, makes it hard to understand why the subnet does not have a gateway from the ssme address space
- privacy extensions: it is very hard to explain to people why they have 3-4 IPv6 addresses assigned to their computer
- multicast instead of broadcast
- way too many ways for autoconfiguration (SLAAC, DHCPv6)
- no real tentative mapping to what people were used to. Every IPv6 presentation I did had to start with “forget everything you know about IPv4”
In the enterprise space, if you mention globally reachable address space, the discussion tends to end pretty fast because “its not secure”. Those people love their NAT.
The nice thing about NAT is it makes the security model easier to reason about.
By this, I don’t mean it’s more secure, because I know it isn’t. But it is a lot easier to see and to explain what has access to what. And the problem with enterprise is that 80% of the work is explaining to other people, usually non-technical or pseudo-technical decision makers, why your design is safe.
I really do think IPv6 missed a trick by not offering that.
It's just one firewall rule at the border to block all inbound traffic to a subnet or a range unless related to an outbound connection. Now you have identical security to a NAT. The huge win is you can forget about port forwarding and later just open the ports you need to the hosts you need.
The price you pay is that it's more difficult to reason about what is accessible from elsewhere, because all devices are represented by your router from the outside, and there are no great ways to opt out of that.
With NAT removed, you've still got the firewall rules, and that's fairly easy to reason about for me: Block anything from outside to inside, except X. Allow A talking to B. Allow B to receive Y from outside.
But we aren’t talking about someone technical glancing at their home routers firewall. We are talking about explaining a network topology to enterprise teams like change management, CISO, etc in large infrastructure environments.
That’s a whole different problem and half the time the people signing off that change either aren’t familiar with the infrastructure (which means explaining the entire context from the ground up) and often aren’t even engineers so need those changes explained in a simplified yet still retaining the technical detail.
These types of organisations mandate CIS / NIST / etc compliance even where it makes zero sense and getting action items in such reports marked as “not required” often takes a meeting in itself with deep architectural discussing with semi-technical people.
Are these types of organisations overly bureaucratic? Absolutely. But that’s typical for any enterprise organisation where processes have been placed to protect individuals and the business from undue risk.
In short, what works for home set ups or even a start up isn’t necessarily what’s going to work for enterprise.
> The nice thing about NAT [...] I really do think IPv6 missed a trick by not offering that
IPv6 supports NAT [0], and nearly all routers make it easy to enable. The primary differences compared to IPv4 is that no-NAT is the default, and that it's more heavily discouraged, but it still works just as well as it does with IPv4.
[0]: In the same way that IPv4 "supports" NAT, meaning that the protocol doesn't officially support it, but it's still possible to implement.
But would we have said the same in 1996 or 2000? Part of the adoption curve seems to be that it took years to abandon some of the bad ideas around IPv6 and readopt some of the better ones from IPv4. And a good chunk of the complexity of IPv6 is that some of the early ideas are very persistent, both in some deployed systems and in people's minds
> But would we have said the same in we 1996 or 2000?
IPv6 the protocol supported NAT just as well back then as it does now, but the software probably didn't. Which goes back to my point [0] [1] that IPv6 is a great protocol with bad tooling and documentation.
> Part of the adoption curve seems to be that it took years to abandon some of the bad ideas around IPv6 and readopt some of the better ones from IPv4.
The only abandoned IPv6 concept that I'm personally aware of is A6 records [2], but I'm pretty young, so I'm sure that there are others that I'm just not aware of. My impression from reading the RFCs and Wikipedia is that IPv6 hasn't changed very much, but that doesn't really mean anything, since I wouldn't expect for current sources to talk about concepts abandoned 20+ years ago.
One good thing about IPv6 is that any reasonable allocation will be large enough to use sizable chunks as functional divisions.
A small company might have a /48. You don't have to be concerned about address space when you just go, ok, first bit is for security zones. Or first 2 bits. Or first 3 bits. Do you need more than 8 security zones?
(Also, ULAs¹ exist, and most people should use them, independent of a possible consideration to not roll out GUAs² in parallel as one would normally do.)
>In the enterprise space, if you mention globally reachable address space, the discussion tends to end pretty fast because “its not secure”. Those people love their NAT.
Was also designed in the early 90s before security was taken seriously.
> There was also unnecessary confusion caused by a rather political decision to make IPv6 require support for IP Security (IPsec), which was an immature technology at the time. This was a definite brake on IPv6 deployment until it was dropped after some years.
I don't know anything about the IPv6 situation, but the way this paragraph just slots in so innocently foreshadows some long wordy Wayland retrospective document on why adoption was so slow where someone from deep in the community slips in 1 short "sure we tried to block screenshots and that might have caused some issues with adoption for some users" paragraph in the middle-end. The innocence of the admission is so mild and context-free that it somehow manages to make itself look guilty.
This is not very substantive, but rather procedural, like this example of an answer doesn't tell you much, but tells you the official paper IDs:
> Actually, we tried that: the "IPv4-Compatible IPv6 address" format was defined in {{RFC3513}} but deprecated by {{RFC4291}} because it turned out to be of no practical use for coexistence or transition.
It is extremely hard (for Brian, but even more so for anyone else, I certainly can't) to give a good answer to that, since you're talking about the absence of utility. People had applications in mind but dismissed them because they either found better ways or it wasn't practical. But that very frequently doesn't result in a "paper trail".
(It's a bit like LLMs having problems with negatives/absences.)
I recently had to set up basic IP-based country detection in Nginx for a project. Parsing and handling IPv4 is trivial. The second I had to account for IPv6 string formats and update the Geo databases to match, the complexity just spiked for no good reason. It feels like we traded address exhaustion for parsing nightmares.
On one of my linux machines the "localhost:8080" did not work after new installation. It resolves to local ipv6 address, while server only listened on ipv4.
After this I go out of my way to disable, remove and nuke ipv6, out of every setup and deployment I do. Ipv6 is already quite complicated, but supporting TWO competing network stacks, with complicated pseudo compatibility, just multiplies unnecessary complexity!
Or, you could've fixed your server's configuration. Probably would've been faster than to "disable, remove and nuke ipv6". In general, the mistake is that it says "0.0.0.0" or "0.0.0.0:8080" somewhere where it should really say "::" or "[::]:8080".
(IPv6 sockets by default accept IPv4 connections, unless you disable that either system-wide or on the specific socket.)
By the way, I do agree the colon was a really poor choice for separating the blocks, when it is also used to separate the port number.
I fixed the problem once for all. Now my program even refuses to start, if IPv6 is enabled. I am not going to spend time debugging problem, that can be easily prevented. Pretty valid solution on private networks and local only kubernetes deployments.
If customer wants proper ipv6 support, we can sign a contract and talk about it. But do not expect me to support some technology for free, just because it is enabled by default.
Nah, you didn't fix anything, you just moved the problem around.
(Worst case, you moved the problem to your finance department, for buying IPv4 address space. But even if you didn't do that, at some point sooner or later you'll get pressure to support IPv6. And then you'll have to "un-fix" everything you did, and fix the actual problem. Maybe it'll be after you're retire, but I wouldn't take bets on that.)
[ed.: best case, you moved the problem to someone else outside your company or scope. Good for you, I guess. Like the sibling post says, address space shortage is an issue for everyone, and personally speaking I would consider it rude to make it other people's problem.]
As I wrote, we use internal networks and k8s. Most of our nodes can not even access internet. I would welcome pressure to support ipv6, it means juicy fresh contract and money.
> you didn't fix anything, you just moved the problem around.
I do not get this attitude "ipv6 is inevitable". So far no customer even asked about it. We have way more urgent problems like cloudflare blocking, ddos from clankers, state regulations...
If the problem actually becomes real in like 20 years. The clankers will probably solve it in like 10 seconds. There is zero benefit right now to deal with headaches of dual routing and addressing.
This attitude is widespread enough to hold the world back by forcing everyone who interacts with the public Internet to support ipv4 (some technology), "for free". So, either way, we're forcing one of them. So, we might as well lean towards supporting the one that isn't hard capped at 4 billion addresses in a world with at least 2x as many devices. Have you ever tried to deal with NAT punchthrough? That's way more difficult to fix than having to properly configure your server.
> Have you ever tried to deal with NAT punchthrough? That's way more difficult to fix than having to properly configure your server.
Yes I did, and I no longer support that either. For my setups it is local private ipv4 networks all the way now! How tailscale or other VPN deals with that is not my problem!
If two nodes are on different networks, they should not be allowed to talk to each other anyway. Seems like security risk! Clean design, simple rules!
A lot of it seems to boil down to "IPv6 was too early". Had IPv6 been developed a couple years later DHCP would have been mature, and SLAAC would have never been invented (since DHCPv6 is fairly obvious when you have good experiences with DHCP). Also it would have given all the alternative protocols (especially OSI) time to try (and likely fail) to gain traction, freeing IPv6 from the obligation to cram in all of their features. IPv6 could have picked a much smaller set of features that were proven useful by other protocols, then swoop in as the much simpler upgrade from IPv4 than any of the competitors
There is no working solution to ipv6 dual WAN failover, 30 years later... A critical design flaw that was simply ignored by the designers despite being used in almost any SME network.
inb4 no you can't have all lan devices have multiple ipv6 addresses and choose for themselves, typically 1 WAN is cheap and the second WAN is expensive/slow and should be used only for WAN1 failover
Inb4 no you can't just advertise new RA, devices on lan can takes minutes to update.
On ipv4, NAT+changing route on router just works, 1-2 seconds failover.
I've always found the most complicated part of IPv6 to be address scopes and source address selection. The fact that one interface can have any number of addresses in different scopes and prefixes complicates things a lot.
Another thing that will always trip up new IPv6 network engineers is solicited-node multicast. You know the theory, computers talk to ff02::1 for neighbor discovery and then you hop onto a real network and see none of that actually happening.
And probably the most complicated thing for network engineers - how to set up firewall rules if machines are constantly changing their addresses.
For developers and security people - just parsing and validating v6 addresses is a whole bunch more work, but at least for this, the tools are available to help you now.
It happened in india mainly due to regulatory pressure[1]. It also helped that around the same time, Reliance (an oil company) launched at a hitherto-unseen pace an entirely new telco (Jio) with only 4G support (now 5G too, but at the time) and zero legacy infrastructure. Airtel (an older telco) was still using ipv4 in lots of cases. However due to pricing pressure[2] and TRAI pressure, they also switched when their 5G rollout happened in 2022. They changed vendors and with that changed the infrastructure as well. So today they are also in good shape ipv6-wise. See also [3]
[2] The pricing pressure was _real_. 4G was the first time networks moved away from circuit switched to IP-based. So the marginal cost equation became better. And no legacy infra to support. By 2020, they also had funding from google and meta.
Obviously economies that rely largely on second hand technology are going to have old technology. Much of Africa is in this bucket. But looking past the extremes, India is at nearly 80% right alongside Germany. They fall in very different average income brackets. So the correlation isn't tight.
I can't see any value in pointing out vague correlation between income and proliferation of a new technology. It's the most obvious of observations.
Yeah, 24 years old. It’s crazy how little has changed in 24 years, other than most of the major sites now supporting IPv6 (with some notable exceptions, such as AWS and GitHub).
In my experience, the IPv6 protocol is much simpler than the IPv4 protocol. However, the IPv6 tooling and documentation is still worse than it is with IPv4, and dual-stack is inherently going to be more complicated than implementing any single protocol, so I do have some sympathy towards "IPv6 is hard".
For example, the IPv6 packet structure [0] is much simpler than the IPv4 packet structure [1]; SLAAC [2] is much simpler than DHCPv4 [3]; IPv6 multicast [4] is much simpler than IGMP [5]; IPv6's lack of NAT simplifies peer-to-peer networking compared to IPv4; ULAs [6] prevent the annoying address conflicts you get with IPv4 [7]; etc.
Almost all computer have multiple interface (virtual or not). Application now need to know which interface the destination is on, and there is no easy data structure to store the interface
How? They're essentially the same as IPv4 addresses; the only difference is that there are way more of them, so address conflicts are much less likely.
> Almost all computer have multiple interface (virtual or not)
Sure, but that's the case with IPv4 too: my cell phone has one IPv4 address over WiFi and another over cellular, and my laptop has one IPv4 address over WiFi and another over Ethernet.
Edit: Ah, I think that eqvinox's comment [0] is what you were getting at here. And yeah, I agree that LLAs are kinda confusing and annoying. The difference is that LLAs aren't routable [1] and don't have an IPv4 analog, while ULAs are routable and are mostly equivalent to IPv4 addresses [2].
You're confusing ULAs (Unique Local Addresses) with LLAs (Link-Local Addresses).
(ULAs don't need the interface specified.)
ULA: fc..:… and fd..:…
LLA: fe80:…
[ed.: By the way, sin6_scope_id is where the interface identifier is stored in struct sockaddr_in6. So, basically every single IPv6 address object you're handling has the field for it.]
This annoys me, especially the last “It takes at least 25 years” rhetoric.
It didn’t take 25 years for SSL. SSH. Gzip encoding on HTTP pages. QUIC. Web to replace NNTP.
GPRS/HSDPA/3G/4G/5G
They all rolled out just fine and were pretty backwards and forwards compatible with each other.
The whole SLAAC/DHCPv6/RA thing is a total clusterfuck. I’m sure there’s many reasons that’s the case but my god. What does your ISP support? Good luck.
We need IPv6 we really do. But it seems to this day the designers of it took everything good/easy/simple and workable about v4 and threw it out. And then are wondering why v6 uptake is so slow.
If they’d designed something that was easy to understand, not too hard to implement quickly and easily, and solved a tangible problem it’d have taken off like a rocket ship. Instead they expected humans to parse hex, which no one does, and massive long numbers that aren’t easily memorable. Sure they threw that one clever :: hack in there but it hardly opened it up to easy accessibility.
Of course hindsight is easy to moan but the “It’s great what’s the problem?” tone of this article annoys me.
I was at some of those IETF meetings in the mid-1990s and attended some early IPv6 working group sessions. We knew the conversion would take time, but I don’t think any of us thought it would be this slow. I was involved with multiple L3 switches and routers from 1997 through 2010. The issue was always that IPv6 basically required lots of boxes in the middle to understand it in order to roll it out, so when would it be commercially necessary? Yes, you can do tunneling and NAT at various points, but it always requires more than just the endpoints. It shows up in DNS and socket APIs. There’s no easy way to determine if a path supports it, and the path can change in an instant due to a route change. All that is very different than SSL or QUIC where only the endpoints have to be involved. That’s why QUIC uses UDP, for instance, so old intermediate devices just see it as a protocol they already know. SSL just assigned port 443 and the “https” protocol in the web URL. If a web client contacts a server on port 443 that doesn’t use SSL, it just fails. To put it another way, the level of the stack that you’re changing matters. SSL and QUIC are really L5+. IPv6 is squarely L3. There are no protocol negotiation mechanism available at L3. So, from a business standpoint, when do you take the hit and integrate it all into the processing pipeline? How do you do that in a way that doesn’t impact your IPv4 forwarding performance, because that’s what the near-term market will judge you on? How do you afford the development and test cost associated with a whole other development (almost double)? If you’re doing software forwarding, the answers are a lot easier. As soon as you’re designing silicon, it’s a lot harder. When you’re under a lot of commercial pressure, it’s difficult to be the one who goes first. And remember that this hardware evolves on roughly 10 year cycles (2 years for design, 3-5 year market sales, 3-5 year depreciation at the customer before they buy new ones). Oh, and customer rollout of IPv6 is a major project with lots of program management and testing, not just buying a box or two. So, yea hindsight is easy. Eventually you get there, but it’s a long road.
> It didn’t take 25 years for SSL. SSH. Gzip encoding on HTTP pages. QUIC. Web to replace NNTP.
All that's required to implement each of those is two computers: 1 client and 1 server. Whereas supporting IPv6 requires every router between the two computers to also support IPv6. Similarly, if your current software doesn't support SSL/SSH/Gzip/etc., it's pretty easy to switch to different software, whereas it's hard or impossible for most people to switch ISPs.
> GPRS/HSDPA/3G/4G/5G
Radio spectrum costs providers millions of dollars, and each new cellular protocol increased spectrum efficiency, so upgrading means that providers can support more users with less spectrum. The problem is that most of the "Western" countries still have lots of IPv4 addresses, so there isn't much cost benefit to switching to IPv6. However, China and India both have lots of users and fewer IPv4 addresses, so there is a cost benefit to switching to IPv6 there, and unsurprisingly both of these countries have really high IPv6 adoption rates.
> The whole SLAAC/DHCPv6/RA thing is a total clusterfuck.
SLAAC is easily the thing I love most about IPv6. It just works. Routers publish advertisements, clients configure themselves. No DHCP server, no address collisions, no worry. What's bugging you about it?
What problem is this actually solving? I've deployed DHCP countless times in all sorts of environments and its "statefulness" was never an issue. Heck, even with SLAAC there's now DAD making it mildly stateful.
Don't get me wrong, SLAAC also works fine, but is it solving anything important enough to justify sacrificing 64 entire address bits for?
DHCP requires explicit configuration; it needs a range that hopefully doesn't conflict with any VPN you use; it needs changes if your range ever gets too small; and it's just another moving part really.
With SLAAC, it's just another implementation detail of the protocol that you usually don't have to even think about, because it just works. That is a clear benefit to me.
FWIW, I'm also on Spectrum (by virtue of the Time Warner acquisition back in the day) and I get 10/10 on that page. That is, after turning off Firefox "Enhanced Privacy Protection" which actually blocked the page from loading at all for some reason. Got 9/10 using Chrome. Both on Linux.
Is it possible that you own your own router and have at some point configured the router to turn up 6 off? I know it is turned off on my router because I had some issues with Verizon ipv6 and tp link in the past.
have that be the invisible bottom layer. come up with a list of 256 common words, one per byte, and have that be the human visible IP address. mentally reading a string of words, however nonsensical, is way easier than a soup of undifferentiated hex digits.
We have that variant of IPv8, it's what CGNAT gives you, especially if you run MAP-E or MAP-T (which are technically not quite NAT, but kinda are, it's… complicated). You take some bits from the port number and essentially repurpose them into part of the address.
It's a nice band-aid technology, no less and no more.
> It didn’t take 25 years for SSL. SSH. Gzip encoding on HTTP pages. QUIC. Web to replace NNTP. GPRS/HSDPA/3G/4G/5G They all rolled out just fine and were pretty backwards and forwards compatible with each other.
You're comparing incremental rollout with migratory rollout for most of these; (not the mobile phone standards.) That's apples and oranges.
You can argue for other proposals. But at the end of the day the best you could've done is steal bits from TCP and UDP port numbers, which is... NAT. Other than that if you want to make a serious claim you need to do the work (or find and understand other people's work. It's not that people haven't tried before. They just failed.)
And, ultimately, this is quite close to typical political problems. Unpopular choices have to be made, for the benefit of all, but people don't like them especially in the short term so they don't get voted for.
> If they’d designed something that was easy to understand, […]
I can't argue on this since it's been far too long since I had to begin understanding IPv4 or IPv6… bane of experience, I guess.
> […] not too hard to implement quickly and easily, […]
As someone actually writing code for routers, IPv6 is easier in quite a few regards, especially link-local addresses make life so much easier. (Yet they're also a frequent point of hate. I absolutely cannot agree with that based on personal experience, like, it's not even within my window of possible opinions.)
> […] expected humans to parse hex […]
You're assuming hex is worse than decimal with binary ranges. Why? Of course it's clear to you that the numbers go to 256 because you're a tech person. But if you know that, you very likely also know hex. (And I'll claim the disjunct sets between these are the same size magnitude.)
Anyway I think I've bulletpointed enough, there's arguments to be made, and they have been made 25 years ago, and 20 years ago, and 15 years ago, and 10 years ago and 5 years ago.
Please, just stop. The herd is moving. If anything had enough sway, it would've had enough sway 15 years ago. Learn some IPv6. There's cool things in there. For example, did you know you can "ping ff02::1%eth0"?
> Incidentally, "IPv8" proponents often ask why IPv6 didn't simply stick some extra bits on the front of IPv4 addresses, instead of inventing a whole new format. Actually, we tried that: the "IPv4-Compatible IPv6 address" format was defined in {{RFC3513}} but deprecated by {{RFC4291}} because it turned out to be of no practical use for coexistence or transition.
Any tl;dr on why/how the simplest solution imaginable would have been "of no practical use for coexistence or transition"? Granted, I understand the other points make a strong enough case by themselves.
> The main reason for IPv6, and its only real reason for existence, was bigger addresses.
Which also allowed for better route aggregation in the core BGP tables.
Better node mobility support. Better multicast support. Genuine link local addresses.
IPv4 had a lot of unfortunate edge cases. I think IPv6's greatest strength and also responsible for it's slow rollout was it's insistence on solving several of these problems at once, along with IPSec as the article notes, and hammering them into the hard requirements for the core stack.
Honestly... Its more machine vocab than human level vocab.
Ipv4 is jsut about able still to hold in your head, have a convo or more importantly you can:
"Shout an ipv4 across the open office floor from your desk to your tech colleague"
If you shout an ipv6 address in public, you jsut seem broken
* It was designed by people who didn't have the full picture and were missing representatives from hardware vendors, small businesses, home network admins and a bunch of other people that will be affected by design.
* It was designed by people who didn't consider the cost of migration and the amount of work that would require (see previous point).
* It was designed by people who lived in an ivory tower of "noone will run dual stack for a long time", "everyone will love to run two completely separate network designs".
* It was designed on a premise that end-to-end, fully accessbile devices are something we actually want and won't cause privacy issues.
I think it should be a study material on how standards and designs by commitee can go wrong if they're not headed by people with extensive experience across the industry with enough authority to push for good solutions.
IPv6 tried to do too much (just like many software "let's refactor this legact code") and was done by people who didn't consider all perspectives and costs (again, like many less experienced architects trying to rewrite legacy software).
Not much more complicated than IPv4. There are more bits. The addresses are longer. It's not hard to grasp if you understand the prerequisites to understanding networking in general.
That applies to pretty much any reasonably complex idea. A new system requires effort to understand it. When you've expended that effort, it's not complicated anymore.
I don't understand this sentiment—as if learning IPv4 was enough work on your part, and now you're entitled to networking protocols never changing anymore.
Just as much as people are not entitled to lack of change, they are not obligated to enjoy, welcome or facilitate change.
What I learned about IPv4 at the turn of the century allows me to comfortably plan and manage networks up to a few thousand nodes, maybe a few tens of thousands.
I don't work in networking anymore. I really don't care about what those who are in that business. What you need to manage contemporary billion-node size networks and interchange between them is not my problem. You try to make it my problem, but I don't care.
I'll continue organizing the very few and very small networks that are still my responsibility using pre-CIDR ideas.
Maybe it becomes impossible some day. I'll deal with it then.
The main complexity of IPv6 is still ha I g to maintain an IPv4 installation. The vast majority of non phone devices do not work in an IPv6 world only because CLAT hasn’t been baked into the OS since the very beginning. It still isn’t a first division tenant on Linux servers, desktops, IoT, or windows. I believe OSX integrates it now
Could with approximately zero services requiring IPv6, the collapsing cost of IPv4 addressing, and it makes IPv6 very much a hidden protocol for phones. When I tether off my phone I get an IPv4 address, the phone may well do a 4:6 translate and then something else does a 6:4 translate. That doesn’t matter, I can still open a socket to 1.1.1.1 from my application.
Had IPv4 been transparently supported IPv6 wouldn’t have taken 30 years and a whole new ecosystem (phones) to get partway there.
If anything, IPv6 is extremely easy to use, especially with SLAAC: On any kind of standard network, you turn on IPv6 on your machine, and, given physical connectivity, bam! You're on the internet.
It only gets complex if you try to micro-manage it.
Oh no, last time I asked on HN I got 24 to 48 easy steps involving a lot more acronyms than this (please don't repeat them).
IPv6 is easy to use only if you let your one router manage everything and you give up control of your home network.
Edit: again, please don't help. There have been HNers trying to help before, but my home network is non trivial and all the "easy" autoconfiguration actually gets in the way.
There are no more acronyms. SLAAC means automatic client configuration. That's the only one you need.
> give up control of your home network.
What does that even mean? What do you gain by deciding your Apple TV should be at 192.168.0.3? With IPv6, you can just `ping appletv` and it works fine. What more "control" do you need?
I mean generally I want fixed IPs on my local network for robustness.
With IPv6 I actually want it more and it becomes possible since we can just use the MAC address as an IP address.
I have IPv6 service at my ISP right now but I'm hesitant to turn it on on my local network because it does make my firewalling concerns much more critical.
> I mean generally I want fixed IPs on my local network for robustness.
Same here, which is why I use DHCPv6. It's pretty easy to set up, nearly everything supports it, and it's super reliable.
The only catch is that Android refuses to support DHCPv6 for some reason, which is kinda annoying since it means that you need to keep SLAAC enabled if you have any Android devices on your network. Which means that your DHCPv6-supporting devices will end up with two addresses, but there aren't any real downsides to that.
You're assuming there is only one internet connection in my home network, for example. The "easy" trick where your ISP gives you routable addresses does not work when there's more than one exit.
Still want to help? :)
And really... everyone is pushing for SSL everywhere - among other things so that the ISP doesn't MITM your traffic.
Why would you allow the ISP to know what machines are inside your home network then?
This doesn’t change anything about the NAT or firewall story, and having two different connections is complex with IPv4 just as well. Aside from being a fairly exotic setup for personal use anyway.
What would your ISP do with the information that there are 73 unique addresses in your network at this point in time? Especially given that devices may mint any number of them for different reasons, so you can’t even really assume that corresponds to the number of physical devices in your network?
You are allowed to state your opinion, as am I. My issue with your opinion is that is grounded in false belief and a lack of knowledge, and rehashing it here reproduces those opinions in others.
NAT is not a security device. A firewall, which will be part of any sane router's NAT implementation, is a security device. NAT is not a firewall, but is often part of one.
Any sane router also uses a firewall for IPv6. A correctly configured router will deny inbound traffic for both v4 and v6. You are not less secure on IPv6.
IPv4 requires a DHCP server. It requires assigning a range of addresses that's usually fairly small, and requires manual configuration as soon as you need more than 254 devices on a network. The range must never conflict with any VPN you use. And there's more. Compare to IPv6: Nothing. All of these just go away.
And concerning the NAT: That's just another word for firewall, which you still have in your router, which still needs to forward packages, and still can decide to block some of them.
What I don’t understand is why coexistence was so important. TFA notes a lot of protocols were in use back then.
Also what’s with all the problems? I’ve had RA packets leak across VLANs via firewall misconfigurations, some my fault and some not. I get that people designing internet protocols had a lot to think about, but why am I fighting stuff like this?
> What I don’t understand is why coexistence was so important.
Military, corporate, tech... it isn't. (If your people like flag day migrations. It's… "a choice".) But if you have to explain to an end user why some things work and some don't, you're just f'd.
And note "coexistence" here means that an end host can implement IPv4 and IPv6 at the same time, without them interacting at all. Imagine if you had to choose between IPv4 and IPv6 on your devices, maybe something like "you need a 2nd network card". Can you imagine anyone switching to the less popular protocol?
The article describes coexistence as both dual-stack and connectivity between single-stack IPv6 and single-stack IPv4 host. And that in the autor's opinion all the complexity is in the latter, not in the dual-stack
You raise a good point that we also should't take dual- stack for granted. But I think the more precise question 'why not dual-stack as the only coexistence option' also seems like a good one, and one the article does not explore or even acknowledge
Dual-stack was the only coexistence option for a long time, until NAT64 came around. There were a whole bunch of attempts at compatibility, e.g. with "::1.1.1.1" and "::ffff:1.1.1.1" as IPv6 addresses, they just didn't go anywhere. (Well, not quite, the latter is in POSIX and in socket libraries around the planet. Doesn't leave the host though. At least it's not supposed to. I have some horror stories…)
NAT64 started happening because it solves real problems — large eyeball networks, particularly mobile phone networks, didn't want to pay for twice as large table sizes on their routers and twice the maintenance effort. So they made IPv6 end hosts capable of connecting to IPv4 systems. But this is 2010 era, IPv6 was ≈15 years old at that point!
The whole world can't migrate all of their hardware on a whim. There was a period of time when it was a very common quip to say that Amazon would have to buy every new IPv6 compatible router in the world for a year if they wanted to upgrade their infra. I don't know if the urban legend is true or not, but the fact that it sounded plausible is a good enough of an example.
My first IPv6 implementation was in 2010-2011 (memory a but fuzzy). Carriers supporting BGP over IPv6 were few, websites over IPv6 were also scarce.
Fast forward 15 years snd the situation has improved quite dramatically.
IPv6 has some quirks that make it harder to digest.
- link local gateway address, makes it hard to understand why the subnet does not have a gateway from the ssme address space
- privacy extensions: it is very hard to explain to people why they have 3-4 IPv6 addresses assigned to their computer
- multicast instead of broadcast
- way too many ways for autoconfiguration (SLAAC, DHCPv6)
- no real tentative mapping to what people were used to. Every IPv6 presentation I did had to start with “forget everything you know about IPv4”
In the enterprise space, if you mention globally reachable address space, the discussion tends to end pretty fast because “its not secure”. Those people love their NAT.
The nice thing about NAT is it makes the security model easier to reason about.
By this, I don’t mean it’s more secure, because I know it isn’t. But it is a lot easier to see and to explain what has access to what. And the problem with enterprise is that 80% of the work is explaining to other people, usually non-technical or pseudo-technical decision makers, why your design is safe.
I really do think IPv6 missed a trick by not offering that.
It's just one firewall rule at the border to block all inbound traffic to a subnet or a range unless related to an outbound connection. Now you have identical security to a NAT. The huge win is you can forget about port forwarding and later just open the ports you need to the hosts you need.
The price you pay is that it's more difficult to reason about what is accessible from elsewhere, because all devices are represented by your router from the outside, and there are no great ways to opt out of that.
With NAT removed, you've still got the firewall rules, and that's fairly easy to reason about for me: Block anything from outside to inside, except X. Allow A talking to B. Allow B to receive Y from outside.
> and that's fairly easy to reason about for me
But we aren’t talking about someone technical glancing at their home routers firewall. We are talking about explaining a network topology to enterprise teams like change management, CISO, etc in large infrastructure environments.
That’s a whole different problem and half the time the people signing off that change either aren’t familiar with the infrastructure (which means explaining the entire context from the ground up) and often aren’t even engineers so need those changes explained in a simplified yet still retaining the technical detail.
These types of organisations mandate CIS / NIST / etc compliance even where it makes zero sense and getting action items in such reports marked as “not required” often takes a meeting in itself with deep architectural discussing with semi-technical people.
Are these types of organisations overly bureaucratic? Absolutely. But that’s typical for any enterprise organisation where processes have been placed to protect individuals and the business from undue risk.
In short, what works for home set ups or even a start up isn’t necessarily what’s going to work for enterprise.
> The nice thing about NAT [...] I really do think IPv6 missed a trick by not offering that
IPv6 supports NAT [0], and nearly all routers make it easy to enable. The primary differences compared to IPv4 is that no-NAT is the default, and that it's more heavily discouraged, but it still works just as well as it does with IPv4.
[0]: In the same way that IPv4 "supports" NAT, meaning that the protocol doesn't officially support it, but it's still possible to implement.
But would we have said the same in 1996 or 2000? Part of the adoption curve seems to be that it took years to abandon some of the bad ideas around IPv6 and readopt some of the better ones from IPv4. And a good chunk of the complexity of IPv6 is that some of the early ideas are very persistent, both in some deployed systems and in people's minds
> But would we have said the same in we 1996 or 2000?
IPv6 the protocol supported NAT just as well back then as it does now, but the software probably didn't. Which goes back to my point [0] [1] that IPv6 is a great protocol with bad tooling and documentation.
> Part of the adoption curve seems to be that it took years to abandon some of the bad ideas around IPv6 and readopt some of the better ones from IPv4.
The only abandoned IPv6 concept that I'm personally aware of is A6 records [2], but I'm pretty young, so I'm sure that there are others that I'm just not aware of. My impression from reading the RFCs and Wikipedia is that IPv6 hasn't changed very much, but that doesn't really mean anything, since I wouldn't expect for current sources to talk about concepts abandoned 20+ years ago.
[0]: https://news.ycombinator.com/item?id=47814070
[1]: https://news.ycombinator.com/item?id=44773999
[2]: https://datatracker.ietf.org/doc/html/rfc6563
One good thing about IPv6 is that any reasonable allocation will be large enough to use sizable chunks as functional divisions.
A small company might have a /48. You don't have to be concerned about address space when you just go, ok, first bit is for security zones. Or first 2 bits. Or first 3 bits. Do you need more than 8 security zones?
(Also, ULAs¹ exist, and most people should use them, independent of a possible consideration to not roll out GUAs² in parallel as one would normally do.)
¹ Unique Local Address, fc..: and fd..:
² Global Unicast Address
It is absolutely a thing in IPv6 as well, but why would you do that.
https://en.wikipedia.org/wiki/IPv6-to-IPv6_Network_Prefix_Tr...
For exactly the reasons I stated
>In the enterprise space, if you mention globally reachable address space, the discussion tends to end pretty fast because “its not secure”. Those people love their NAT.
Was also designed in the early 90s before security was taken seriously.
> There was also unnecessary confusion caused by a rather political decision to make IPv6 require support for IP Security (IPsec), which was an immature technology at the time. This was a definite brake on IPv6 deployment until it was dropped after some years.
I don't know anything about the IPv6 situation, but the way this paragraph just slots in so innocently foreshadows some long wordy Wayland retrospective document on why adoption was so slow where someone from deep in the community slips in 1 short "sure we tried to block screenshots and that might have caused some issues with adoption for some users" paragraph in the middle-end. The innocence of the admission is so mild and context-free that it somehow manages to make itself look guilty.
This is not very substantive, but rather procedural, like this example of an answer doesn't tell you much, but tells you the official paper IDs:
> Actually, we tried that: the "IPv4-Compatible IPv6 address" format was defined in {{RFC3513}} but deprecated by {{RFC4291}} because it turned out to be of no practical use for coexistence or transition.
Why/how did it turn out?
> Why/how did it turn out?
It is extremely hard (for Brian, but even more so for anyone else, I certainly can't) to give a good answer to that, since you're talking about the absence of utility. People had applications in mind but dismissed them because they either found better ways or it wasn't practical. But that very frequently doesn't result in a "paper trail".
(It's a bit like LLMs having problems with negatives/absences.)
I recently had to set up basic IP-based country detection in Nginx for a project. Parsing and handling IPv4 is trivial. The second I had to account for IPv6 string formats and update the Geo databases to match, the complexity just spiked for no good reason. It feels like we traded address exhaustion for parsing nightmares.
On one of my linux machines the "localhost:8080" did not work after new installation. It resolves to local ipv6 address, while server only listened on ipv4.
After this I go out of my way to disable, remove and nuke ipv6, out of every setup and deployment I do. Ipv6 is already quite complicated, but supporting TWO competing network stacks, with complicated pseudo compatibility, just multiplies unnecessary complexity!
Or, you could've fixed your server's configuration. Probably would've been faster than to "disable, remove and nuke ipv6". In general, the mistake is that it says "0.0.0.0" or "0.0.0.0:8080" somewhere where it should really say "::" or "[::]:8080".
(IPv6 sockets by default accept IPv4 connections, unless you disable that either system-wide or on the specific socket.)
By the way, I do agree the colon was a really poor choice for separating the blocks, when it is also used to separate the port number.
I fixed the problem once for all. Now my program even refuses to start, if IPv6 is enabled. I am not going to spend time debugging problem, that can be easily prevented. Pretty valid solution on private networks and local only kubernetes deployments.
If customer wants proper ipv6 support, we can sign a contract and talk about it. But do not expect me to support some technology for free, just because it is enabled by default.
Yeah, I’ll sign a contract so you can “support” a configurable bind address. That’s post-doc level of comp-sci stuff right there.
I’ll also sign the “numbers bigger than 2^32” contract and a “weird looking characters in text” contract.
Nah, you didn't fix anything, you just moved the problem around.
(Worst case, you moved the problem to your finance department, for buying IPv4 address space. But even if you didn't do that, at some point sooner or later you'll get pressure to support IPv6. And then you'll have to "un-fix" everything you did, and fix the actual problem. Maybe it'll be after you're retire, but I wouldn't take bets on that.)
[ed.: best case, you moved the problem to someone else outside your company or scope. Good for you, I guess. Like the sibling post says, address space shortage is an issue for everyone, and personally speaking I would consider it rude to make it other people's problem.]
As I wrote, we use internal networks and k8s. Most of our nodes can not even access internet. I would welcome pressure to support ipv6, it means juicy fresh contract and money.
> you didn't fix anything, you just moved the problem around.
I do not get this attitude "ipv6 is inevitable". So far no customer even asked about it. We have way more urgent problems like cloudflare blocking, ddos from clankers, state regulations...
If the problem actually becomes real in like 20 years. The clankers will probably solve it in like 10 seconds. There is zero benefit right now to deal with headaches of dual routing and addressing.
> at some point sooner or later you'll get pressure to support IPv6
I've been told that for 20+ years. Nothing has changed.
This attitude is widespread enough to hold the world back by forcing everyone who interacts with the public Internet to support ipv4 (some technology), "for free". So, either way, we're forcing one of them. So, we might as well lean towards supporting the one that isn't hard capped at 4 billion addresses in a world with at least 2x as many devices. Have you ever tried to deal with NAT punchthrough? That's way more difficult to fix than having to properly configure your server.
> Have you ever tried to deal with NAT punchthrough? That's way more difficult to fix than having to properly configure your server.
Yes I did, and I no longer support that either. For my setups it is local private ipv4 networks all the way now! How tailscale or other VPN deals with that is not my problem!
If two nodes are on different networks, they should not be allowed to talk to each other anyway. Seems like security risk! Clean design, simple rules!
A lot of it seems to boil down to "IPv6 was too early". Had IPv6 been developed a couple years later DHCP would have been mature, and SLAAC would have never been invented (since DHCPv6 is fairly obvious when you have good experiences with DHCP). Also it would have given all the alternative protocols (especially OSI) time to try (and likely fail) to gain traction, freeing IPv6 from the obligation to cram in all of their features. IPv6 could have picked a much smaller set of features that were proven useful by other protocols, then swoop in as the much simpler upgrade from IPv4 than any of the competitors
There is no working solution to ipv6 dual WAN failover, 30 years later... A critical design flaw that was simply ignored by the designers despite being used in almost any SME network.
inb4 no you can't have all lan devices have multiple ipv6 addresses and choose for themselves, typically 1 WAN is cheap and the second WAN is expensive/slow and should be used only for WAN1 failover
Inb4 no you can't just advertise new RA, devices on lan can takes minutes to update.
On ipv4, NAT+changing route on router just works, 1-2 seconds failover.
I've always found the most complicated part of IPv6 to be address scopes and source address selection. The fact that one interface can have any number of addresses in different scopes and prefixes complicates things a lot.
Another thing that will always trip up new IPv6 network engineers is solicited-node multicast. You know the theory, computers talk to ff02::1 for neighbor discovery and then you hop onto a real network and see none of that actually happening.
And probably the most complicated thing for network engineers - how to set up firewall rules if machines are constantly changing their addresses.
For developers and security people - just parsing and validating v6 addresses is a whole bunch more work, but at least for this, the tools are available to help you now.
India on around 80% in the apnic labs active measurement of end users.
https://stats.labs.apnic.net/ipv6/in
They report nearly a billion users, predominantly in mobile.
So, "only" 750 to 800 million users. Think about that: 3x the population of the USA using it most of the time, in one economy.
Here's the rankings:
https://stats.labs.apnic.net/ipv6/XA?o=cINw30x1r1
This is a different measure to Google's. They measure different things,
It happened in india mainly due to regulatory pressure[1]. It also helped that around the same time, Reliance (an oil company) launched at a hitherto-unseen pace an entirely new telco (Jio) with only 4G support (now 5G too, but at the time) and zero legacy infrastructure. Airtel (an older telco) was still using ipv4 in lots of cases. However due to pricing pressure[2] and TRAI pressure, they also switched when their 5G rollout happened in 2022. They changed vendors and with that changed the infrastructure as well. So today they are also in good shape ipv6-wise. See also [3]
[1] https://www.dot.gov.in/ipv6-transition-across-stakeholders Edit: hey look the govt drupal page is broken again, shocker. here is another source: https://icrier.org/pdf/IPv6_Transition.pdf
[2] The pricing pressure was _real_. 4G was the first time networks moved away from circuit switched to IP-based. So the marginal cost equation became better. And no legacy infra to support. By 2020, they also had funding from google and meta.
[3] https://broadbandindiaforum.in/wp-content/uploads/2022/08/Re...
Now compare average income to see how much this matters.
Depends what you are selling and to whom. Meanwhile, India wanted to get a lot of people online and this appears to suit their needs.
I'm confused. What's your point?
Obviously economies that rely largely on second hand technology are going to have old technology. Much of Africa is in this bucket. But looking past the extremes, India is at nearly 80% right alongside Germany. They fall in very different average income brackets. So the correlation isn't tight.
I can't see any value in pointing out vague correlation between income and proliferation of a new technology. It's the most obvious of observations.
very transparent.
what has _that_ got to do with ipv6 adoption/usage ?
afaics, it probably has more to do with large indian-isp’s f.e. jio adopting ipv6.
"The IPv6 mess" by DJB
https://cr.yp.to/djbdns/ipv6mess.html
How I wish that djb time stamped his articles, as I feel like this article is over a decade old but I can’t tell with certainty.
https://web.archive.org/web/20021203075817/https://cr.yp.to/...
Yeah, 24 years old. It’s crazy how little has changed in 24 years, other than most of the major sites now supporting IPv6 (with some notable exceptions, such as AWS and GitHub).
It's not like anything has changed, except the running out of IPv4 part.
Edit: or maybe they added 12 more extra configuration protocols to manage, in the name of "ease of use".
In my experience, the IPv6 protocol is much simpler than the IPv4 protocol. However, the IPv6 tooling and documentation is still worse than it is with IPv4, and dual-stack is inherently going to be more complicated than implementing any single protocol, so I do have some sympathy towards "IPv6 is hard".
For example, the IPv6 packet structure [0] is much simpler than the IPv4 packet structure [1]; SLAAC [2] is much simpler than DHCPv4 [3]; IPv6 multicast [4] is much simpler than IGMP [5]; IPv6's lack of NAT simplifies peer-to-peer networking compared to IPv4; ULAs [6] prevent the annoying address conflicts you get with IPv4 [7]; etc.
[0]: https://en.wikipedia.org/wiki/IPv6_packet#Fixed_header
[1]: https://en.wikipedia.org/wiki/IPv4#Packet_structure
[2]: https://en.wikipedia.org/wiki/IPv6_address#Stateless_address...
[3]: https://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Pro...
[4]: https://en.wikipedia.org/wiki/IPv6#Multicasting
[5]: https://en.wikipedia.org/wiki/Internet_Group_Management_Prot...
[6]: https://en.wikipedia.org/wiki/Unique_local_address
[7]: https://stackoverflow.com/a/52374482/30512871
ULA give more trouble than what it solves.
Almost all computer have multiple interface (virtual or not). Application now need to know which interface the destination is on, and there is no easy data structure to store the interface
> ULA give more trouble than what it solves.
How? They're essentially the same as IPv4 addresses; the only difference is that there are way more of them, so address conflicts are much less likely.
> Almost all computer have multiple interface (virtual or not)
Sure, but that's the case with IPv4 too: my cell phone has one IPv4 address over WiFi and another over cellular, and my laptop has one IPv4 address over WiFi and another over Ethernet.
Edit: Ah, I think that eqvinox's comment [0] is what you were getting at here. And yeah, I agree that LLAs are kinda confusing and annoying. The difference is that LLAs aren't routable [1] and don't have an IPv4 analog, while ULAs are routable and are mostly equivalent to IPv4 addresses [2].
[0]: https://news.ycombinator.com/item?id=47814154
[1]: https://en.wikipedia.org/wiki/Link-local_address
[2]: https://en.wikipedia.org/wiki/Unique_local_address
You're confusing ULAs (Unique Local Addresses) with LLAs (Link-Local Addresses).
(ULAs don't need the interface specified.)
ULA: fc..:… and fd..:…
LLA: fe80:…
[ed.: By the way, sin6_scope_id is where the interface identifier is stored in struct sockaddr_in6. So, basically every single IPv6 address object you're handling has the field for it.]
This annoys me, especially the last “It takes at least 25 years” rhetoric.
It didn’t take 25 years for SSL. SSH. Gzip encoding on HTTP pages. QUIC. Web to replace NNTP. GPRS/HSDPA/3G/4G/5G They all rolled out just fine and were pretty backwards and forwards compatible with each other.
The whole SLAAC/DHCPv6/RA thing is a total clusterfuck. I’m sure there’s many reasons that’s the case but my god. What does your ISP support? Good luck.
We need IPv6 we really do. But it seems to this day the designers of it took everything good/easy/simple and workable about v4 and threw it out. And then are wondering why v6 uptake is so slow.
If they’d designed something that was easy to understand, not too hard to implement quickly and easily, and solved a tangible problem it’d have taken off like a rocket ship. Instead they expected humans to parse hex, which no one does, and massive long numbers that aren’t easily memorable. Sure they threw that one clever :: hack in there but it hardly opened it up to easy accessibility.
Of course hindsight is easy to moan but the “It’s great what’s the problem?” tone of this article annoys me.
I was at some of those IETF meetings in the mid-1990s and attended some early IPv6 working group sessions. We knew the conversion would take time, but I don’t think any of us thought it would be this slow. I was involved with multiple L3 switches and routers from 1997 through 2010. The issue was always that IPv6 basically required lots of boxes in the middle to understand it in order to roll it out, so when would it be commercially necessary? Yes, you can do tunneling and NAT at various points, but it always requires more than just the endpoints. It shows up in DNS and socket APIs. There’s no easy way to determine if a path supports it, and the path can change in an instant due to a route change. All that is very different than SSL or QUIC where only the endpoints have to be involved. That’s why QUIC uses UDP, for instance, so old intermediate devices just see it as a protocol they already know. SSL just assigned port 443 and the “https” protocol in the web URL. If a web client contacts a server on port 443 that doesn’t use SSL, it just fails. To put it another way, the level of the stack that you’re changing matters. SSL and QUIC are really L5+. IPv6 is squarely L3. There are no protocol negotiation mechanism available at L3. So, from a business standpoint, when do you take the hit and integrate it all into the processing pipeline? How do you do that in a way that doesn’t impact your IPv4 forwarding performance, because that’s what the near-term market will judge you on? How do you afford the development and test cost associated with a whole other development (almost double)? If you’re doing software forwarding, the answers are a lot easier. As soon as you’re designing silicon, it’s a lot harder. When you’re under a lot of commercial pressure, it’s difficult to be the one who goes first. And remember that this hardware evolves on roughly 10 year cycles (2 years for design, 3-5 year market sales, 3-5 year depreciation at the customer before they buy new ones). Oh, and customer rollout of IPv6 is a major project with lots of program management and testing, not just buying a box or two. So, yea hindsight is easy. Eventually you get there, but it’s a long road.
> It didn’t take 25 years for SSL. SSH. Gzip encoding on HTTP pages. QUIC. Web to replace NNTP.
All that's required to implement each of those is two computers: 1 client and 1 server. Whereas supporting IPv6 requires every router between the two computers to also support IPv6. Similarly, if your current software doesn't support SSL/SSH/Gzip/etc., it's pretty easy to switch to different software, whereas it's hard or impossible for most people to switch ISPs.
> GPRS/HSDPA/3G/4G/5G
Radio spectrum costs providers millions of dollars, and each new cellular protocol increased spectrum efficiency, so upgrading means that providers can support more users with less spectrum. The problem is that most of the "Western" countries still have lots of IPv4 addresses, so there isn't much cost benefit to switching to IPv6. However, China and India both have lots of users and fewer IPv4 addresses, so there is a cost benefit to switching to IPv6 there, and unsurprisingly both of these countries have really high IPv6 adoption rates.
> Instead they expected humans to parse hex, which no one does
Of all aspects of IPv6 you took the only one that doesn't complicate implementations and can easily be swapped if you wanted.
Wait til you’ve got to copy & paste em, or see em comingled with hw addresses
Wait till you find an application that accepts 1.65793 as an IPv4 address. Or 134744072.
(by the way, this was way less of a dumb peculiarity back when IPv6 was designed)> The whole SLAAC/DHCPv6/RA thing is a total clusterfuck.
SLAAC is easily the thing I love most about IPv6. It just works. Routers publish advertisements, clients configure themselves. No DHCP server, no address collisions, no worry. What's bugging you about it?
What problem is this actually solving? I've deployed DHCP countless times in all sorts of environments and its "statefulness" was never an issue. Heck, even with SLAAC there's now DAD making it mildly stateful.
Don't get me wrong, SLAAC also works fine, but is it solving anything important enough to justify sacrificing 64 entire address bits for?
* privacy addresses are great
* deriving additional addresses for specific functions is great (e.g. XLAT464/CLAT)
* you don't get collisions when you lose your DHCP lease database
* as Brian says, DHCP wasn't quite there yet when IPv6 was designed
* ability to proactively change things by sending different RAs (e.g. router or prefix failover, though these don't work as well as one would hope)
* ability to encode mnemonic information into those 64 bits (when configuring addresses statically)
* optimization for the routing layers in assuming prefixes mostly won't be longer than /64
… and probably 20 others that don't come to mind immediately. I didn't even spend seconds thinking about the ones I listed here.
DHCP requires explicit configuration; it needs a range that hopefully doesn't conflict with any VPN you use; it needs changes if your range ever gets too small; and it's just another moving part really.
With SLAAC, it's just another implementation detail of the protocol that you usually don't have to even think about, because it just works. That is a clear benefit to me.
When it fail, you find there is no option to tune its behaviour.
Plug in a rough router and see quickly you can find it.
What kind of failure are you referring to? What would you want to tune? You can still easily locate all devices on your network.
> What does your ISP support?
My ISP is Spectrum. They get a 0/10 on IPv6 support on this test page [1].
[1] https://test-ipv6.com
FWIW, I'm also on Spectrum (by virtue of the Time Warner acquisition back in the day) and I get 10/10 on that page. That is, after turning off Firefox "Enhanced Privacy Protection" which actually blocked the page from loading at all for some reason. Got 9/10 using Chrome. Both on Linux.
Is it possible that you own your own router and have at some point configured the router to turn up 6 off? I know it is turned off on my router because I had some issues with Verizon ipv6 and tp link in the past.
Good idea–on my list of to-check items.
how do you encode 128 bits without making a long number? and not using hex?
have that be the invisible bottom layer. come up with a list of 256 common words, one per byte, and have that be the human visible IP address. mentally reading a string of words, however nonsensical, is way easier than a soup of undifferentiated hex digits.
Easier if you’re a native English speaker. Harder if you’re not.
My only gripe with IPv6 addresses is they look too similar to MAC addresses. But as a representation, I think they’re absolutely fine.
Far easier to use ipv8, which just has 5 octets instead of 4.
We have that variant of IPv8, it's what CGNAT gives you, especially if you run MAP-E or MAP-T (which are technically not quite NAT, but kinda are, it's… complicated). You take some bits from the port number and essentially repurpose them into part of the address.
It's a nice band-aid technology, no less and no more.
That still means replacing every part of the chain.
> It didn’t take 25 years for SSL. SSH. Gzip encoding on HTTP pages. QUIC. Web to replace NNTP. GPRS/HSDPA/3G/4G/5G They all rolled out just fine and were pretty backwards and forwards compatible with each other.
You're comparing incremental rollout with migratory rollout for most of these; (not the mobile phone standards.) That's apples and oranges.
You can argue for other proposals. But at the end of the day the best you could've done is steal bits from TCP and UDP port numbers, which is... NAT. Other than that if you want to make a serious claim you need to do the work (or find and understand other people's work. It's not that people haven't tried before. They just failed.)
And, ultimately, this is quite close to typical political problems. Unpopular choices have to be made, for the benefit of all, but people don't like them especially in the short term so they don't get voted for.
> If they’d designed something that was easy to understand, […]
I can't argue on this since it's been far too long since I had to begin understanding IPv4 or IPv6… bane of experience, I guess.
> […] not too hard to implement quickly and easily, […]
As someone actually writing code for routers, IPv6 is easier in quite a few regards, especially link-local addresses make life so much easier. (Yet they're also a frequent point of hate. I absolutely cannot agree with that based on personal experience, like, it's not even within my window of possible opinions.)
> […] expected humans to parse hex […]
You're assuming hex is worse than decimal with binary ranges. Why? Of course it's clear to you that the numbers go to 256 because you're a tech person. But if you know that, you very likely also know hex. (And I'll claim the disjunct sets between these are the same size magnitude.)
Anyway I think I've bulletpointed enough, there's arguments to be made, and they have been made 25 years ago, and 20 years ago, and 15 years ago, and 10 years ago and 5 years ago.
Please, just stop. The herd is moving. If anything had enough sway, it would've had enough sway 15 years ago. Learn some IPv6. There's cool things in there. For example, did you know you can "ping ff02::1%eth0"?
> Incidentally, "IPv8" proponents often ask why IPv6 didn't simply stick some extra bits on the front of IPv4 addresses, instead of inventing a whole new format. Actually, we tried that: the "IPv4-Compatible IPv6 address" format was defined in {{RFC3513}} but deprecated by {{RFC4291}} because it turned out to be of no practical use for coexistence or transition.
Any tl;dr on why/how the simplest solution imaginable would have been "of no practical use for coexistence or transition"? Granted, I understand the other points make a strong enough case by themselves.
> The main reason for IPv6, and its only real reason for existence, was bigger addresses.
Which also allowed for better route aggregation in the core BGP tables.
Better node mobility support. Better multicast support. Genuine link local addresses.
IPv4 had a lot of unfortunate edge cases. I think IPv6's greatest strength and also responsible for it's slow rollout was it's insistence on solving several of these problems at once, along with IPSec as the article notes, and hammering them into the hard requirements for the core stack.
And that's what you should do, since you're forcing the protocol update you should take the opportunity that might not come later
Didn't happen. The swamp aside, Traffic engineering drives most disaggregation. Better in some senses, but not orders of magnitude better I think.
Honestly... Its more machine vocab than human level vocab.
Ipv4 is jsut about able still to hold in your head, have a convo or more importantly you can: "Shout an ipv4 across the open office floor from your desk to your tech colleague"
If you shout an ipv6 address in public, you jsut seem broken
It is like it is because:
* It was designed by people who didn't have the full picture and were missing representatives from hardware vendors, small businesses, home network admins and a bunch of other people that will be affected by design.
* It was designed by people who didn't consider the cost of migration and the amount of work that would require (see previous point).
* It was designed by people who lived in an ivory tower of "noone will run dual stack for a long time", "everyone will love to run two completely separate network designs".
* It was designed on a premise that end-to-end, fully accessbile devices are something we actually want and won't cause privacy issues.
I think it should be a study material on how standards and designs by commitee can go wrong if they're not headed by people with extensive experience across the industry with enough authority to push for good solutions.
IPv6 tried to do too much (just like many software "let's refactor this legact code") and was done by people who didn't consider all perspectives and costs (again, like many less experienced architects trying to rewrite legacy software).
It's not. I learned how IPv6 worked SO LONG AGO that I really can't understand remaining confusion.
It's not complicated because you understand it? Okay then
Not much more complicated than IPv4. There are more bits. The addresses are longer. It's not hard to grasp if you understand the prerequisites to understanding networking in general.
That applies to pretty much any reasonably complex idea. A new system requires effort to understand it. When you've expended that effort, it's not complicated anymore.
I don't understand this sentiment—as if learning IPv4 was enough work on your part, and now you're entitled to networking protocols never changing anymore.
Just as much as people are not entitled to lack of change, they are not obligated to enjoy, welcome or facilitate change.
What I learned about IPv4 at the turn of the century allows me to comfortably plan and manage networks up to a few thousand nodes, maybe a few tens of thousands.
I don't work in networking anymore. I really don't care about what those who are in that business. What you need to manage contemporary billion-node size networks and interchange between them is not my problem. You try to make it my problem, but I don't care.
I'll continue organizing the very few and very small networks that are still my responsibility using pre-CIDR ideas.
Maybe it becomes impossible some day. I'll deal with it then.
if it was easier to use and less of a PITA, it wouldn't be taking decades.
The main complexity of IPv6 is still ha I g to maintain an IPv4 installation. The vast majority of non phone devices do not work in an IPv6 world only because CLAT hasn’t been baked into the OS since the very beginning. It still isn’t a first division tenant on Linux servers, desktops, IoT, or windows. I believe OSX integrates it now
Could with approximately zero services requiring IPv6, the collapsing cost of IPv4 addressing, and it makes IPv6 very much a hidden protocol for phones. When I tether off my phone I get an IPv4 address, the phone may well do a 4:6 translate and then something else does a 6:4 translate. That doesn’t matter, I can still open a socket to 1.1.1.1 from my application.
Had IPv4 been transparently supported IPv6 wouldn’t have taken 30 years and a whole new ecosystem (phones) to get partway there.
If anything, IPv6 is extremely easy to use, especially with SLAAC: On any kind of standard network, you turn on IPv6 on your machine, and, given physical connectivity, bam! You're on the internet.
It only gets complex if you try to micro-manage it.
> especially with SLAAC
Oh no, last time I asked on HN I got 24 to 48 easy steps involving a lot more acronyms than this (please don't repeat them).
IPv6 is easy to use only if you let your one router manage everything and you give up control of your home network.
Edit: again, please don't help. There have been HNers trying to help before, but my home network is non trivial and all the "easy" autoconfiguration actually gets in the way.
There are no more acronyms. SLAAC means automatic client configuration. That's the only one you need.
> give up control of your home network.
What does that even mean? What do you gain by deciding your Apple TV should be at 192.168.0.3? With IPv6, you can just `ping appletv` and it works fine. What more "control" do you need?
> you can just `ping appletv` and it works fine.
How many service does it take to make this work?
mDNS is quite fragile.
I haven’t seen a bog-standard router yet that didn’t just do it out of the box.
I mean generally I want fixed IPs on my local network for robustness.
With IPv6 I actually want it more and it becomes possible since we can just use the MAC address as an IP address.
I have IPv6 service at my ISP right now but I'm hesitant to turn it on on my local network because it does make my firewalling concerns much more critical.
> I mean generally I want fixed IPs on my local network for robustness.
Same here, which is why I use DHCPv6. It's pretty easy to set up, nearly everything supports it, and it's super reliable.
The only catch is that Android refuses to support DHCPv6 for some reason, which is kinda annoying since it means that you need to keep SLAAC enabled if you have any Android devices on your network. Which means that your DHCPv6-supporting devices will end up with two addresses, but there aren't any real downsides to that.
> since we can just use the MAC address as an IP address
With IPv4 you need to remember ... one number per machine. The one at the end, since it's usually a /24 and everything has the same prefix.
I'm sure it's trivial to remember mac addresses from different vendors with no connection to each other too :)
> Isn't it really stable hostnames that you want?
Hostnames are another layer. Your apple tv example may advertise itself on its own. My toys don't all do that.
That’s kind of my point, though. There is no reason at all to remember IP addresses.
> I mean generally I want fixed IPs on my local network for robustness.
What do you mean by robustness? Isn't it really stable hostnames that you want? I don't understand how fixed IPs increase resilience (to what?).
> I'm hesitant to turn it on on my local network because it does make my firewalling concerns much more critical.
Block everything coming in from outside the network. Allow established connections. That's all there is to it.
You're assuming there is only one internet connection in my home network, for example. The "easy" trick where your ISP gives you routable addresses does not work when there's more than one exit.
Still want to help? :)
And really... everyone is pushing for SSL everywhere - among other things so that the ISP doesn't MITM your traffic.
Why would you allow the ISP to know what machines are inside your home network then?
This doesn’t change anything about the NAT or firewall story, and having two different connections is complex with IPv4 just as well. Aside from being a fairly exotic setup for personal use anyway.
What would your ISP do with the information that there are 73 unique addresses in your network at this point in time? Especially given that devices may mint any number of them for different reasons, so you can’t even really assume that corresponds to the number of physical devices in your network?
> Aside from being a fairly exotic setup for personal use anyway.
So I should cancel one of my pipes because the "commitee" overcomplicated things in the name of autoconfiguration?
> What would your ISP do with the information that there are 73 unique addresses in your network at this point in time?
Sell it of course. Good info for targeting marketing/political propaganda per household.
> I haven’t seen a bog-standard router yet that didn’t just do it out of the box.
Which one, the one from ISP A or the one from ISP B? :)
> So I should cancel one of my pipes because the "commitee" overcomplicated things in the name of autoconfiguration?
That is absolutely not what I said. It’s a more complex setup than a single connection with either protocol, and can be solved with both.
> Which one, the one from ISP A or the one from ISP B? :)
Realistically it is going to return an A record with both addresses, maybe also the link-local one, any works locally. That is a non-issue.
What firewalling? You don’t have an ipv4 firewall?
the internet, in very large volume, disagrees. Am I not allowed to document the widely held common sentiment?
You are allowed to state your opinion, as am I. My issue with your opinion is that is grounded in false belief and a lack of knowledge, and rehashing it here reproduces those opinions in others.
So, like ipv4, but you lose the protection and privacy afforded by the NAT?
What protection? What privacy? Smoke and mirrors, mostly.
NAT is a firewall with extra steps. IPv6 reduces complexity. Privacy (illusion of it, anyway, just like in ipv4 NAT) is handled by private addresses.
…and if you really want to, NAT for ipv6 just works.
NAT is not a security device. A firewall, which will be part of any sane router's NAT implementation, is a security device. NAT is not a firewall, but is often part of one.
Any sane router also uses a firewall for IPv6. A correctly configured router will deny inbound traffic for both v4 and v6. You are not less secure on IPv6.
IPv4 requires a DHCP server. It requires assigning a range of addresses that's usually fairly small, and requires manual configuration as soon as you need more than 254 devices on a network. The range must never conflict with any VPN you use. And there's more. Compare to IPv6: Nothing. All of these just go away.
And concerning the NAT: That's just another word for firewall, which you still have in your router, which still needs to forward packages, and still can decide to block some of them.
The dhcp server is in the router, just like you need a router for slaac.
What I don’t understand is why coexistence was so important. TFA notes a lot of protocols were in use back then.
Also what’s with all the problems? I’ve had RA packets leak across VLANs via firewall misconfigurations, some my fault and some not. I get that people designing internet protocols had a lot to think about, but why am I fighting stuff like this?
> What I don’t understand is why coexistence was so important.
Military, corporate, tech... it isn't. (If your people like flag day migrations. It's… "a choice".) But if you have to explain to an end user why some things work and some don't, you're just f'd.
And note "coexistence" here means that an end host can implement IPv4 and IPv6 at the same time, without them interacting at all. Imagine if you had to choose between IPv4 and IPv6 on your devices, maybe something like "you need a 2nd network card". Can you imagine anyone switching to the less popular protocol?
The article describes coexistence as both dual-stack and connectivity between single-stack IPv6 and single-stack IPv4 host. And that in the autor's opinion all the complexity is in the latter, not in the dual-stack
You raise a good point that we also should't take dual- stack for granted. But I think the more precise question 'why not dual-stack as the only coexistence option' also seems like a good one, and one the article does not explore or even acknowledge
Dual-stack was the only coexistence option for a long time, until NAT64 came around. There were a whole bunch of attempts at compatibility, e.g. with "::1.1.1.1" and "::ffff:1.1.1.1" as IPv6 addresses, they just didn't go anywhere. (Well, not quite, the latter is in POSIX and in socket libraries around the planet. Doesn't leave the host though. At least it's not supposed to. I have some horror stories…)
NAT64 started happening because it solves real problems — large eyeball networks, particularly mobile phone networks, didn't want to pay for twice as large table sizes on their routers and twice the maintenance effort. So they made IPv6 end hosts capable of connecting to IPv4 systems. But this is 2010 era, IPv6 was ≈15 years old at that point!
The whole world can't migrate all of their hardware on a whim. There was a period of time when it was a very common quip to say that Amazon would have to buy every new IPv6 compatible router in the world for a year if they wanted to upgrade their infra. I don't know if the urban legend is true or not, but the fact that it sounded plausible is a good enough of an example.
And packet forwarding was done in hardware pipelines, can't software update them to handle new protocols.