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> The IPv6 designers made a fundamental conceptual mistake: they designed the IPv6 address space as an alternative to the IPv4 address space, rather than an ext

> The IPv6 designers made a fundamental conceptual mistake: they designed the IPv6 address space as an alternative to the IPv4 address space, rather than an extension to the IPv4 address space Very much this. I'm so given up on hopes for IPv6, that I feel it is almost the time to create IPv8, designing it to be an extension to IPv4, and ditching IPv6 completely,

rcxdude 5y ago
How would making it an extension help? You still have the fundamental compatibility problem that you can't address the wider address space with a narrower address.
- jeroenhd 5y ago
  You'd probably be encapsulating "IPv5" traffic in IPv4 traffic towards known translation routers at ISP networks. CG-NAT with some extra advertisements and routing knowledge, basically. You'd be stuck with an abysmal MTU for "IPv5" though, because you need that wrapper and the world doesn't seem to want an MTU larger than 1500 outside internal networks.
  - cesarb 5y ago
    > You'd probably be encapsulating "IPv5" traffic in IPv4 traffic towards known translation routers at ISP networks. That's what 6to4 does. When enabled, it encapsulates IPv6 traffic in IPv4 packets and sends them towards a well-known anycast IPv4 address, and the return IPv6 traffic is sent towards a well-known anycast network, where a router encapsulates it in IPv4 packets and sends them towards the IPv4 address contained within the IPv6 address. I find it amusing that all these "IPv5" proposals either cannot work, or do the same as something which already exists for IPv6 (and in this case, it works; I've used 6to4 for a while).
    - ay 5y ago
      You ought to use the past tense when speaking about 6to4.. As much as technically I think it was a brilliant idea (a whole /48 assigned to each existing IPv4 address owner), it failed because of the tragedy of commons.
      - jeroenhd 5y ago
        One of the problems with 6to4 that make it hard to deploy in well-configured networks is the DNS problem. Google runs a 6to4 DNS but warns that DNSSEC will be broken by design, and clients would need their own translation software on the software side to solve the problem. 6to4 gateways are still a thing, you can traceroute 192.88.99.1 to find the nearest gateway if you have IPv4 connectivity. I've got one seven hops from my device, but I've also got a static IPv4 address so I have little need for a gateway.
    - jeroenhd 5y ago
      You're right about the concept, of course, but 6to4 gateways don't work the other way around. You can't reach an IPv6 network through them, you can only reach IPv4 from IPv6. My silly "IPv5" solution would also have a way for IPv4 sources to send IPv5 traffic upstream. As complex as some may find IPv6, I find it a lot simpler and more independent of routing services than many proposals for alternatives. The weirdest one I've seen involves concatenation two IP headers, giving everyone one network IP for ISPs and such and one client IP for the individual hosts, but that's just replicating IPv6 with extra steps and an even smaller MTU.
- cesarb 5y ago
  > You still have the fundamental compatibility problem that you can't address the wider address space with a narrower address. There are ways to work around that. All of them (and some more) were tried and/or are in use with IPv6: https://en.wikipedia.org/wiki/IPv6_transition_mechanisms https://en.wikipedia.org/wiki/IPv6_transition_mechanisms
  - rcxdude 5y ago
    Those are all ways of allowing ipv6 to address ipv4, (or tunning ipv6 over ipv4 infrastructure) which is fairly easy to manage (getting the reverse connection still involves NAT though). None of them are ways of allowing ipv4 to address ipv6, because that fundamentally doesn't work by the pigeonhole principle.
diegocg 5y ago
IPv6 has already won. Google and Facebook report 50% or higher IPv6 traffic in the united states. There is absolutely no chance of a replacement at this point
- feldrim 5y ago
  26 years later, still not being the default while gaining about %50 of only for a couple of giant companies -excluding the fact that most traffic is not the users but many other third parties- I would not call this statistic a win. If I connect to a Wi-Fi in a Starbucks with IPv6 by default or my recently bought mobile line comes with IPv6, then I would say it is a win. It is a huge improvement but the story of the failure is a good topic for academic research for future protocols.
  - realityking 5y ago
    > my recently bought mobile line comes with IPv6, then I would say it is a win I’m surprised it doesn’t. In Europe most providers only give you IPv6 and CGNAT IPv4. Even my landline does that.
    - feldrim 5y ago
      It's getting more and more used by time but yes,ts not that common. I'm here in Estonia and the mobile carriers -that I used- use (CGNAT) IPv4.
  - detaro 5y ago
    > my recently bought mobile line comes with IPv6 it quite likely does today, IPv6 is common with mobile carriers.
- deleted 5y ago
  [deleted]
- AtlasBarfed 5y ago
  Almost all ipv6 traffic is mobile, which is running under far more totalitarian execution environments (mobile OSs) and centrally controlled addressing. While that is a ipv6 success, that is greenfield. And the telecoms are basically running a huge ipv6 nat when they need ipv4 routing. Which is heretical to ipv6. The issue of migration of existing ipv4 is still sucky. Meanwhile normal desktop OS and infrastructure and consumer routers are (20 years after this article) a disaster.
0x006A 5y ago
Strange time to give up on IPv6. Global availability is ~36% now and many countries it crossed 50% in 2021. If anything its time to ditch IPv4 once and for all.
- zaphar 5y ago
  And yet we are probably multiple decades away from 90% adoption and it is quite possible given the level of coordination required that we may never get to 100% adoption. We are more than 20 years in and I am still required to support ipv4 if I want to reach the market reliably while ipv6 has little incentive for me to support other than a general sense of goodwill/responsibility and the vague hope that someday it will result in an even larger network. We need an expanded address space. The ipv6 rollout is proving to be one of the least effective ways to get it in practical terms.
  - KarlKemp 5y ago
    The statistics would seem to support a slightly more optimistic view: https://www.google.com/intl/en/ipv6/statistics.html https://www.google.com/intl/en/ipv6/statistics.html I see a linear trend that, once adoption started in earnest around 2015 has seen about 30% of users being converted to iPv6. At some point, it’ll be more common to run into issues with v4, which will drive more adoption. The toolchain now needs. To support v6 and defaults using it will become more common. The conversion will limit the scarcity of v4 to some extend, but continued growth of internet access and connected devices adds pressure on the other side.
  - q-big 5y ago
    > And yet we are probably multiple decades away from 90% adoption and it is quite possible given the level of coordination required that we may never get to 100% adoption. 100% adaption will never come. Just look how many companies still use COBOL software that was developed in the 70s. The question rather is: when will IPv4 become insignificant enough that your company won't have to care about it anymore?
  - throw0101a 5y ago
    > And yet we are probably multiple decades away from 90% adoption IPv4 prices were in the mid-US$30/IP in early 2021 and they're now around mid-$50: * https://auctions.ipv4.global https://auctions.ipv4.global I think The Market™ will decide that trying to run IPv4 in a lot of places will be too expensive, and that end-points will get assigned IPv6 with various translation mechanisms being run for the 'legacy' Internet. Heck, even AWS if finally allowing IPv6-only infrastructure: * https://aws.amazon.com/blogs/networking-and-content-delivery/introducing-ipv6-only-subnets-and-ec2-instances/ https://aws.amazon.com/blogs/networking-and-content-delivery...
belter 5y ago
Could not agree more. They also forgot to make sure every single of the most common networking tools, would have to work with IPv6 with no flaws. Then there is the issue of equivalence of RFC 1918 for IPv6, another whole can of worms... https://serverfault.com/questions/216602/what-is-the-ipv6-equivalent-to-ipv4-rfc1918-addresses https://serverfault.com/questions/216602/what-is-the-ipv6-eq...
gtsop 5y ago
Don't give up hope. The iot begs for ipv6 addresses and companies beg for adding iot capable chips on everything. It's a sad driving force, but it is a driving force.
jeroenhd 5y ago
IPv6 has an entire network range reserved for the IPv4 address space. You need an IPv4 capable router set up, but you can natively reach IPv4 from IPv6. The problem is connectivity the other way around, but it's simply impossible to cram more address space into IPv4. You'd need a protocol on top of IPv4 and special routing software or hardware on either end of the connection to hack backwards compatibility into the old address ranges.
- midasuni 5y ago
  That’s fine, nat can do that just fine. But ipv6 fans hate nat, so instead we end up with proponents saying “run dual stack” and those who don’t want the added overhead simply ignoring ipv6 entirely
  - smitty1e 5y ago
    It's not just the added overhead. For many, having a *private* IPv4 space is not just a feature, but a requirement. The idea of a completely globally flat address space makes perfect technical sense. However, policy sense may differ as Your Mileage Varies.
    - duhast 5y ago
      Nothing in the IPv6 spec forces you to publicly advertise your globally flat address space. Even if you do choose to advertise your prefixes publicly, you can still use firewalls to block some or even all traffic.
      - zinekeller 5y ago
        Not this discussion again. Okay, you can indeed do that... but how do you get an address is the another question. You might answer "Just go to the RIR", sure, but ASNs aren't given willy-nilly, they need to prove that they'll need different routing needs for external peering, and some RIRs do insist on this. The most loose RIR in terns of regulations is RIPE, but what about other companies in other parts of the world?
throw0101a 5y ago
> I'm so given up on hopes for IPv6, that I feel it is almost the time to create IPv8, designing it to be an extension to IPv4, and ditching IPv6 completely, And new code has to be written to take advantage of that new protocol. And that new code has to be deployed on every single network element. Don't forget a new DNS record type so that old code is not confused by a new address format. And then everyone has to be convinced to deploy that new code and start assigning those new addresses. Just like had/has to be done IPv6. IPv8 will/would have the exact same issues with deployment as IPv6.
StillBored 5y ago
I don't think its even that hard to create an extension at this point. Partially because we are mostly there already. Call the extension "NAT tagging" and add a 24-bit NAT "tag" which reflects the bottom 24 bits of the 10.x space. Every machine with a private ipv4 appends this as its source tag, and it becomes the responsibility of NAT tagging aware NATs to notice the NAT tag on inbound packets and route them appropriately. Client machines which are themselves aware make sure to preserve the source tag when sending packets back to the NAT'ed machine. The tag of every existing public ipv4 is 0.0.0. The only tricky part at this point is encoding all these extra bits in a way which is ignored by existing ipv4 stacks. Although, figure out how to check for it in a handshake of some form (easier with stateful protocols like TCP) and it could hide outside of the IP header itself. Non compliant endpoints continue to suffer the existing port forwarding/etc issues that exist with current NAT's while updated machines can directly address each other. The various hacks (already in use) to the HTTP hostname fields also solve the problem for tag unaware machines addressing public https servers. This gives every existing IPv4 address 24 bits of additionally public routable addressing without having to upgrade a single core router/etc.

rcxdude 5y ago

How would making it an extension help? You still have the fundamental compatibility problem that you can't address the wider address space with a narrower address.

jeroenhd 5y ago
You'd probably be encapsulating "IPv5" traffic in IPv4 traffic towards known translation routers at ISP networks. CG-NAT with some extra advertisements and routing knowledge, basically. You'd be stuck with an abysmal MTU for "IPv5" though, because you need that wrapper and the world doesn't seem to want an MTU larger than 1500 outside internal networks.
- cesarb 5y ago
  > You'd probably be encapsulating "IPv5" traffic in IPv4 traffic towards known translation routers at ISP networks. That's what 6to4 does. When enabled, it encapsulates IPv6 traffic in IPv4 packets and sends them towards a well-known anycast IPv4 address, and the return IPv6 traffic is sent towards a well-known anycast network, where a router encapsulates it in IPv4 packets and sends them towards the IPv4 address contained within the IPv6 address. I find it amusing that all these "IPv5" proposals either cannot work, or do the same as something which already exists for IPv6 (and in this case, it works; I've used 6to4 for a while).
  - ay 5y ago
    You ought to use the past tense when speaking about 6to4.. As much as technically I think it was a brilliant idea (a whole /48 assigned to each existing IPv4 address owner), it failed because of the tragedy of commons.
    - jeroenhd 5y ago
      One of the problems with 6to4 that make it hard to deploy in well-configured networks is the DNS problem. Google runs a 6to4 DNS but warns that DNSSEC will be broken by design, and clients would need their own translation software on the software side to solve the problem. 6to4 gateways are still a thing, you can traceroute 192.88.99.1 to find the nearest gateway if you have IPv4 connectivity. I've got one seven hops from my device, but I've also got a static IPv4 address so I have little need for a gateway.
  - jeroenhd 5y ago
    You're right about the concept, of course, but 6to4 gateways don't work the other way around. You can't reach an IPv6 network through them, you can only reach IPv4 from IPv6. My silly "IPv5" solution would also have a way for IPv4 sources to send IPv5 traffic upstream. As complex as some may find IPv6, I find it a lot simpler and more independent of routing services than many proposals for alternatives. The weirdest one I've seen involves concatenation two IP headers, giving everyone one network IP for ISPs and such and one client IP for the individual hosts, but that's just replicating IPv6 with extra steps and an even smaller MTU.
cesarb 5y ago
> You still have the fundamental compatibility problem that you can't address the wider address space with a narrower address. There are ways to work around that. All of them (and some more) were tried and/or are in use with IPv6: https://en.wikipedia.org/wiki/IPv6_transition_mechanisms https://en.wikipedia.org/wiki/IPv6_transition_mechanisms
- rcxdude 5y ago
  Those are all ways of allowing ipv6 to address ipv4, (or tunning ipv6 over ipv4 infrastructure) which is fairly easy to manage (getting the reverse connection still involves NAT though). None of them are ways of allowing ipv4 to address ipv6, because that fundamentally doesn't work by the pigeonhole principle.

diegocg 5y ago

IPv6 has already won. Google and Facebook report 50% or higher IPv6 traffic in the united states. There is absolutely no chance of a replacement at this point

feldrim 5y ago
26 years later, still not being the default while gaining about %50 of only for a couple of giant companies -excluding the fact that most traffic is not the users but many other third parties- I would not call this statistic a win. If I connect to a Wi-Fi in a Starbucks with IPv6 by default or my recently bought mobile line comes with IPv6, then I would say it is a win. It is a huge improvement but the story of the failure is a good topic for academic research for future protocols.
- realityking 5y ago
  > my recently bought mobile line comes with IPv6, then I would say it is a win I’m surprised it doesn’t. In Europe most providers only give you IPv6 and CGNAT IPv4. Even my landline does that.
  - feldrim 5y ago
    It's getting more and more used by time but yes,ts not that common. I'm here in Estonia and the mobile carriers -that I used- use (CGNAT) IPv4.
- detaro 5y ago
  > my recently bought mobile line comes with IPv6 it quite likely does today, IPv6 is common with mobile carriers.
deleted 5y ago
[deleted]
AtlasBarfed 5y ago
Almost all ipv6 traffic is mobile, which is running under far more totalitarian execution environments (mobile OSs) and centrally controlled addressing. While that is a ipv6 success, that is greenfield. And the telecoms are basically running a huge ipv6 nat when they need ipv4 routing. Which is heretical to ipv6. The issue of migration of existing ipv4 is still sucky. Meanwhile normal desktop OS and infrastructure and consumer routers are (20 years after this article) a disaster.

0x006A 5y ago

Strange time to give up on IPv6. Global availability is ~36% now and many countries it crossed 50% in 2021. If anything its time to ditch IPv4 once and for all.

zaphar 5y ago
And yet we are probably multiple decades away from 90% adoption and it is quite possible given the level of coordination required that we may never get to 100% adoption. We are more than 20 years in and I am still required to support ipv4 if I want to reach the market reliably while ipv6 has little incentive for me to support other than a general sense of goodwill/responsibility and the vague hope that someday it will result in an even larger network. We need an expanded address space. The ipv6 rollout is proving to be one of the least effective ways to get it in practical terms.
- KarlKemp 5y ago
  The statistics would seem to support a slightly more optimistic view: https://www.google.com/intl/en/ipv6/statistics.html https://www.google.com/intl/en/ipv6/statistics.html I see a linear trend that, once adoption started in earnest around 2015 has seen about 30% of users being converted to iPv6. At some point, it’ll be more common to run into issues with v4, which will drive more adoption. The toolchain now needs. To support v6 and defaults using it will become more common. The conversion will limit the scarcity of v4 to some extend, but continued growth of internet access and connected devices adds pressure on the other side.
- q-big 5y ago
  > And yet we are probably multiple decades away from 90% adoption and it is quite possible given the level of coordination required that we may never get to 100% adoption. 100% adaption will never come. Just look how many companies still use COBOL software that was developed in the 70s. The question rather is: when will IPv4 become insignificant enough that your company won't have to care about it anymore?
- throw0101a 5y ago
  > And yet we are probably multiple decades away from 90% adoption IPv4 prices were in the mid-US$30/IP in early 2021 and they're now around mid-$50: * https://auctions.ipv4.global https://auctions.ipv4.global I think The Market™ will decide that trying to run IPv4 in a lot of places will be too expensive, and that end-points will get assigned IPv6 with various translation mechanisms being run for the 'legacy' Internet. Heck, even AWS if finally allowing IPv6-only infrastructure: * https://aws.amazon.com/blogs/networking-and-content-delivery/introducing-ipv6-only-subnets-and-ec2-instances/ https://aws.amazon.com/blogs/networking-and-content-delivery...

belter 5y ago

Could not agree more. They also forgot to make sure every single of the most common networking tools, would have to work with IPv6 with no flaws. Then there is the issue of equivalence of RFC 1918 for IPv6, another whole can of worms... https://serverfault.com/questions/216602/what-is-the-ipv6-equivalent-to-ipv4-rfc1918-addresses https://serverfault.com/questions/216602/what-is-the-ipv6-eq...

gtsop 5y ago

Don't give up hope. The iot begs for ipv6 addresses and companies beg for adding iot capable chips on everything. It's a sad driving force, but it is a driving force.

jeroenhd 5y ago

IPv6 has an entire network range reserved for the IPv4 address space. You need an IPv4 capable router set up, but you can natively reach IPv4 from IPv6. The problem is connectivity the other way around, but it's simply impossible to cram more address space into IPv4. You'd need a protocol on top of IPv4 and special routing software or hardware on either end of the connection to hack backwards compatibility into the old address ranges.

midasuni 5y ago
That’s fine, nat can do that just fine. But ipv6 fans hate nat, so instead we end up with proponents saying “run dual stack” and those who don’t want the added overhead simply ignoring ipv6 entirely
- smitty1e 5y ago
  It's not just the added overhead. For many, having a *private* IPv4 space is not just a feature, but a requirement. The idea of a completely globally flat address space makes perfect technical sense. However, policy sense may differ as Your Mileage Varies.
  - duhast 5y ago
    Nothing in the IPv6 spec forces you to publicly advertise your globally flat address space. Even if you do choose to advertise your prefixes publicly, you can still use firewalls to block some or even all traffic.
    - zinekeller 5y ago
      Not this discussion again. Okay, you can indeed do that... but how do you get an address is the another question. You might answer "Just go to the RIR", sure, but ASNs aren't given willy-nilly, they need to prove that they'll need different routing needs for external peering, and some RIRs do insist on this. The most loose RIR in terns of regulations is RIPE, but what about other companies in other parts of the world?

throw0101a 5y ago

> I'm so given up on hopes for IPv6, that I feel it is almost the time to create IPv8, designing it to be an extension to IPv4, and ditching IPv6 completely, And new code has to be written to take advantage of that new protocol. And that new code has to be deployed on every single network element. Don't forget a new DNS record type so that old code is not confused by a new address format. And then everyone has to be convinced to deploy that new code and start assigning those new addresses. Just like had/has to be done IPv6. IPv8 will/would have the exact same issues with deployment as IPv6.

StillBored 5y ago

I don't think its even that hard to create an extension at this point. Partially because we are mostly there already. Call the extension "NAT tagging" and add a 24-bit NAT "tag" which reflects the bottom 24 bits of the 10.x space. Every machine with a private ipv4 appends this as its source tag, and it becomes the responsibility of NAT tagging aware NATs to notice the NAT tag on inbound packets and route them appropriately. Client machines which are themselves aware make sure to preserve the source tag when sending packets back to the NAT'ed machine. The tag of every existing public ipv4 is 0.0.0. The only tricky part at this point is encoding all these extra bits in a way which is ignored by existing ipv4 stacks. Although, figure out how to check for it in a handshake of some form (easier with stateful protocols like TCP) and it could hide outside of the IP header itself. Non compliant endpoints continue to suffer the existing port forwarding/etc issues that exist with current NAT's while updated machines can directly address each other. The various hacks (already in use) to the HTTP hostname fields also solve the problem for tag unaware machines addressing public https servers. This gives every existing IPv4 address 24 bits of additionally public routable addressing without having to upgrade a single core router/etc.