7 ms·

> In a nutshell, an IPv4x packet is a normal IPv4 packet, just with 128‑bit addresses. The first 32 bits of both the source and target address sit in their usua

> In a nutshell, an IPv4x packet is a normal IPv4 packet, just with 128‑bit addresses. The first 32 bits of both the source and target address sit in their usual place in the header, while the extra 96 bits of each address (the “subspace”) are tucked into the first 24 bytes of the IPv4 body. A flag in the header marks the packet as IPv4x, so routers that understand the extension can read the full address, while routers that don’t simply ignore the extra data and forward it as usual. So you have to ship new code to every 'network element' to support IPv4x. Just like with IPv6. So you have to update DNS to create new resource record types ("A" is hard-coded to 32-bits) to support the new longer addresses, and have all user-land code start asking for, using, and understanding the new record replies. Just like with IPv6. (And their DNS idea won't work—or won't work differently than IPv6: a lot of legacy code did not have room in data structures for multiple reply types: sure you'd get the "A" but unless you updated the code to get the "AX" address (for ipv4X addresses) you could never get to the longer with address… just like IPv6 needed code updates to recognize AAAA, otherwise you were A-only.) You need to update socket APIs to hold new data structures for longer addresses so your app can tell the kernel to send packets to the new addresses. Just like with IPv6. A single residential connection that gets a single IPv4 address also gets to use all the /96 'behind it' with this IPv4x proposal? People complain about the "wastefulness" of /64s now, and this is even more so (to the tune of 32 bits). You'd probably be better served with pushing the new bits to the other end… like… * https://en.wikipedia.org/wiki/IPv6#IPv4-mapped_IPv6_addresses https://en.wikipedia.org/wiki/IPv6#IPv4-mapped_IPv6_addresse...

lxgr 7mo ago
Yes, I was wondering if I was missing something reading the hypothetical: This is still splits the Internet into two incompatible (but often bridged etc.) subnetworks, one on the v4, one on the v4x side, right? It just so happens that, unlike for v6, v4 and v4x have some "implicit bridges" built-in (i.e. between everything in v4 and everything in v4x that happens to have the last 96 bits unset). Not sure if that actually makes anything better or just kicks the can down the road in an even more messy way.
- xorcist 7mo ago
  > everything in v4x that happens to have the last 96 bits unset That's pretty much identical to 6in4 and similar proposals. The Internet really needs a variant of the "So, you have an anti spam proposal" meme that used to be popular. Yes, it kill fresh ideas in the bud sometimes, but it also helps establish a cultural baseline for what is constructive discussion. Nobody needs to hear about the same old ideas that were subsumed by IPv6 because they required a flag day, delayed address exhaustion only about six months, or exploded routing tables to impossible sizes. If you have new ideas, let's hear them, but the discussion around v6 has been on constant repeat since before it was finalized and that's not useful to anyone.
  - lxgr 7mo ago
    I feel like the greatest vindication of v6 is that I’m reading the same old arguments served over a quietly working v6 connection more often than not. While people were busy betting on the non-adoption of v6, it just happened. —Sent from my IPv6 phone
    - setr 7mo ago
      I don’t know if it anyone was really making bets around it… it’s just kind of individually meaningless to implement support for until it’s already popular, because you still have to support IPv4 in full until the day you can remove it entirely
  - throw0101d 7mo ago
    > The Internet really needs a variant of the "So, you have an anti spam proposal" meme that used to be popular. For those unfamiliar: * https://craphound.com/spamsolutions.txt https://craphound.com/spamsolutions.txt
    - dullcrisp 7mo ago
      Public reluctance to accept weird new forms of money has turned out to be a myth.
arka2147483647 7mo ago
The advantage, as i see it, is that this could be done incrementally. Every new router/firmware/os could add support, until support is ubiquitous. Contrast this with ip6, which is a completely new system, and thus has a chicken and egg problem.
- deleted 7mo ago
  [deleted]
- Gigachad 7mo ago
  That is how v6 worked though. Every router and consumer device supports v6 and has for a very long time now. The holdup ended up being ISPs. Today it seems most ISPs support it but have it behind an off by default toggle.
  - IncreasePosts 7mo ago
    Wouldn't this proposal not require isps to do anything? They already assign every user a unique ipv4 address. Then, with this proposal, if I want to have a bunch of computers behind that single ipv4 ip, I could do it without relying on NAT tricks
    - ianburrell 7mo ago
      There aren’t enough IPv4 addresses to give everyone one. That is why ISPs use CGNAT to hide multiple customers behind one IP address. Something that just uses IPv4 won’t work without making the extra layer visible. That may not have been apparent then but it is now.
    - jcranmer 7mo ago
      > Wouldn't this proposal not require isps to do anything? They already assign every user a unique ipv4 address. The reason there's an IPv4 address shortage is because ISPs assign every user a unique IPv4 address. In this alternative timeline, ISPs would have to give users less-than-an-IPv4 address, which probably means a single IPv4x address if we're being realistic and assuming that ISPs are taking the path of least resistance.
bmacho 7mo ago
> Just like with IPv6. Yes, but the compatibility is very very easy to support for both hardware vendors, softwares, sysadmins etc. Some things might need a gentle stroke (mostly just enlarge a single bitfield) but after that everything just works, hardware, software, websites, operators. A protocol is a social problem, and ipv6 fails exactly there.
- Gigachad 7mo ago
  What slowed ipv6 wasn’t the design of ipv6, it was the invention of NAT and CGNAT. Even still. The rollout is still progressing, and new systems like Matter are IPv6 only.
  - bigstrat2003 7mo ago
    What stymies IPv6 is human laziness more than anything else. It's not hard to set up. Every network I run has been dual stack for 10 years now, with minimal additional effort. People are just too lazy to put forth even a minimal effort when they believe that there's no payoff to it.
    - XorNot 7mo ago
      This goes the other direction too. I just this second fixed a problem with incredibly slow SSH connections because a host lookup which returned an IPv4 address instantly was waiting 10+ seconds for an IPv6 response which would never come. Now I'm sure I can fix DNSmasq to do something sensible here, but the defaults didn't even break - they worked in the most annoying way possible where had I just disabled IPv6 that would've fixed the entire problem right away. Dual stack has some incredibly stupid defaults.
      - iso1631 7mo ago
        > Dual stack has some incredibly stupid defaults. Dual stack is the problem, and it's not going away in the next 20 years. Single stack ipv4, fine, if your applications support it then great. Single stack ipv6, fine, if your applications support it then great. Dual stack is just horrendous, you can never be sure what stack you're on when you work at a higher level.
billpg 7mo ago
No, in this hypothetical, routers that don't know about IPv4x will still route based on the top 32 bits of the address which is still in the same place for IPv4 packets. If your machine on your desk and the other machine across the internet both understand IPv4x, but no other machines in the middle do, you'll still get your packets across.
- kolinko 7mo ago
  Well no, all the routers on your subnet need to understand it. So let’s say your internet provider owns x.x.x.x, it receives a packet directed to you at x.x.x.x.y.y… , forwards it to your network, but your local router has old software and treats all packages to x.x.x.x.* as directed to it. You never receive any medssagea directly to you evem though your computer would recognise IPv4x. It would be a clusterfuck.
  - billpg 7mo ago
    Your local machine isn't on the IPv4 internet if it doesn't have a globally routable IPv4 address. Your home router that sits on the end of a single IPv4 address would need to know about IPv4x, but in this parallel world you'd buy a router that does.
    - kolinko 7mo ago
      Of course you are, just behind NAT. If your device has it's own public IPv4 address then you don't need IPv4x, IPv6 or whatever else.
    - zadikian 7mo ago
      "all routers on your subnet need to understand that" I thought that meant the same thing you said
  - digitalPhonix 7mo ago
    How would anything on the internet know about x.x.x.x.y.y…? Your computer knows it’s connected to an old router because dhcp gave it x.x.x.x address and not x.x.x.x... so it knows it’s running in old v4 mode. And it can still send outbound to a v4x address that it knows about.
theamk 7mo ago
you are missing the point - updating "network elements" was never the problem. Linux kernel has IPv6 support since 2.6. RedHat got IPv6 in 2008. Nginx got it in 2010. And yet there plenty of IPv4-systems out there. why? Software updates scale _very well_ - once author updates, all users get the latest version. The important part is sysadmin time and config files - _those_ don't scale at all, and someone needs to invest effort in every single system out there. That's where IPv6 really dropped the ball by having dual-stack the default. In IPv4x, there is no dual-stack. I upgrade my OS, and suddenly I can use IPv4x addresses... but I don't have to - all my configs are still valid, and if my router is not compatible, all devices still fall back to IPv4-compatible short addresses, but are using IPv4x stack. I upgrade the home router and suddenly some devices get IPv4x address... but it is all transparent to me - my router's NAT takes care of that if my upstream (ISP) or a client device are not IPv4x-capable. I have my small office network which is on the mix IPv4 and IPv4x addresses. Most Windows/Linux machines are on IPv4x, but that old network printer and security controller still have IPv4 address (with router translating responses). It still all works together. There is only one firewall rule set, there is only one monitoring tool, etc... My ACL list on NAS server has mix of IPv4 and IPv4x in the same list... So this is a very stark contrast to IPv6 mess, where you have to bring up a whole parallel network, setup a second router config, set up a separate firewall set, make a second parallel set of addresses, basically setup a whole separate network - just to be able to bring up a single IPv6 device. (Funny enough, I bet one _could_ accelerate IPv6 deployment a lot by have a standard that _requires_ 6to4/4to6/NAT64 technology in each IPv6 network... but instead the IPv6 supporters went into all-or-nothing approach)
- billpg 7mo ago
  "I bet one _could_ accelerate IPv6 deployment a lot by have a standard ..." ahem https://owl.billpg.com/sixgate/ https://owl.billpg.com/sixgate/
  - theamk 7mo ago
    "The good thing about standards is that there are so many to choose from."
- 7mo ago
Animats 7mo ago
If you put part of the address in the body space, you can't encrypt the entire body. IPv6 adoption has been linear for the last two decades. Currently, 48% of Google traffic is IPv6.[1] It was 30% in 2020. That's low, because Google is blocked in China. Google sees China as 6% IPv6, but China is really around 77%. Sometimes it takes a long time to convert infrastructure. Half the Northeast Corridor track is still on 25Hz. There's still some 40Hz power around Niagara Falls. San Francisco got rid of the last PG&E DC service a few years ago. It took from 1948 to 1994 to convert all US freight rail stock to roller bearings.[2] European freight rail is still using couplers obsolete and illegal in the US since 1900. (There's an effort underway to fix this. Hopefully it will go better than Eurocoupler from the 1980s. Passenger rail uses completely different couplers, and doesn't uncouple much.)[3] [1] https://www.google.com/intl/en/ipv6/statistics.html https://www.google.com/intl/en/ipv6/statistics.html [2] https://www.youtube.com/watch?v=R-1EZ6K7bpQ https://www.youtube.com/watch?v=R-1EZ6K7bpQ [2] https://rail-research.europa.eu/european-dac-delivery-programme/ https://rail-research.europa.eu/european-dac-delivery-progra...
- riffic 7mo ago
  should also bring to mind that there's a technological leapfrogging effect in stages of development which it seems clear that China has taken advantage of. https://en.wikipedia.org/wiki/Leapfrogging https://en.wikipedia.org/wiki/Leapfrogging
deleted 7mo ago
[deleted]

lxgr 7mo ago

Yes, I was wondering if I was missing something reading the hypothetical: This is still splits the Internet into two incompatible (but often bridged etc.) subnetworks, one on the v4, one on the v4x side, right? It just so happens that, unlike for v6, v4 and v4x have some "implicit bridges" built-in (i.e. between everything in v4 and everything in v4x that happens to have the last 96 bits unset). Not sure if that actually makes anything better or just kicks the can down the road in an even more messy way.

xorcist 7mo ago
> everything in v4x that happens to have the last 96 bits unset That's pretty much identical to 6in4 and similar proposals. The Internet really needs a variant of the "So, you have an anti spam proposal" meme that used to be popular. Yes, it kill fresh ideas in the bud sometimes, but it also helps establish a cultural baseline for what is constructive discussion. Nobody needs to hear about the same old ideas that were subsumed by IPv6 because they required a flag day, delayed address exhaustion only about six months, or exploded routing tables to impossible sizes. If you have new ideas, let's hear them, but the discussion around v6 has been on constant repeat since before it was finalized and that's not useful to anyone.
- lxgr 7mo ago
  I feel like the greatest vindication of v6 is that I’m reading the same old arguments served over a quietly working v6 connection more often than not. While people were busy betting on the non-adoption of v6, it just happened. —Sent from my IPv6 phone
  - setr 7mo ago
    I don’t know if it anyone was really making bets around it… it’s just kind of individually meaningless to implement support for until it’s already popular, because you still have to support IPv4 in full until the day you can remove it entirely
- throw0101d 7mo ago
  > The Internet really needs a variant of the "So, you have an anti spam proposal" meme that used to be popular. For those unfamiliar: * https://craphound.com/spamsolutions.txt https://craphound.com/spamsolutions.txt
  - dullcrisp 7mo ago
    Public reluctance to accept weird new forms of money has turned out to be a myth.

arka2147483647 7mo ago

The advantage, as i see it, is that this could be done incrementally. Every new router/firmware/os could add support, until support is ubiquitous. Contrast this with ip6, which is a completely new system, and thus has a chicken and egg problem.

deleted 7mo ago
[deleted]
Gigachad 7mo ago
That is how v6 worked though. Every router and consumer device supports v6 and has for a very long time now. The holdup ended up being ISPs. Today it seems most ISPs support it but have it behind an off by default toggle.
- IncreasePosts 7mo ago
  Wouldn't this proposal not require isps to do anything? They already assign every user a unique ipv4 address. Then, with this proposal, if I want to have a bunch of computers behind that single ipv4 ip, I could do it without relying on NAT tricks
  - ianburrell 7mo ago
    There aren’t enough IPv4 addresses to give everyone one. That is why ISPs use CGNAT to hide multiple customers behind one IP address. Something that just uses IPv4 won’t work without making the extra layer visible. That may not have been apparent then but it is now.
  - jcranmer 7mo ago
    > Wouldn't this proposal not require isps to do anything? They already assign every user a unique ipv4 address. The reason there's an IPv4 address shortage is because ISPs assign every user a unique IPv4 address. In this alternative timeline, ISPs would have to give users less-than-an-IPv4 address, which probably means a single IPv4x address if we're being realistic and assuming that ISPs are taking the path of least resistance.

bmacho 7mo ago

> Just like with IPv6. Yes, but the compatibility is very very easy to support for both hardware vendors, softwares, sysadmins etc. Some things might need a gentle stroke (mostly just enlarge a single bitfield) but after that everything just works, hardware, software, websites, operators. A protocol is a social problem, and ipv6 fails exactly there.

Gigachad 7mo ago
What slowed ipv6 wasn’t the design of ipv6, it was the invention of NAT and CGNAT. Even still. The rollout is still progressing, and new systems like Matter are IPv6 only.
- bigstrat2003 7mo ago
  What stymies IPv6 is human laziness more than anything else. It's not hard to set up. Every network I run has been dual stack for 10 years now, with minimal additional effort. People are just too lazy to put forth even a minimal effort when they believe that there's no payoff to it.
  - XorNot 7mo ago
    This goes the other direction too. I just this second fixed a problem with incredibly slow SSH connections because a host lookup which returned an IPv4 address instantly was waiting 10+ seconds for an IPv6 response which would never come. Now I'm sure I can fix DNSmasq to do something sensible here, but the defaults didn't even break - they worked in the most annoying way possible where had I just disabled IPv6 that would've fixed the entire problem right away. Dual stack has some incredibly stupid defaults.
    - iso1631 7mo ago
      > Dual stack has some incredibly stupid defaults. Dual stack is the problem, and it's not going away in the next 20 years. Single stack ipv4, fine, if your applications support it then great. Single stack ipv6, fine, if your applications support it then great. Dual stack is just horrendous, you can never be sure what stack you're on when you work at a higher level.

billpg 7mo ago

No, in this hypothetical, routers that don't know about IPv4x will still route based on the top 32 bits of the address which is still in the same place for IPv4 packets. If your machine on your desk and the other machine across the internet both understand IPv4x, but no other machines in the middle do, you'll still get your packets across.

kolinko 7mo ago
Well no, all the routers on your subnet need to understand it. So let’s say your internet provider owns x.x.x.x, it receives a packet directed to you at x.x.x.x.y.y… , forwards it to your network, but your local router has old software and treats all packages to x.x.x.x.* as directed to it. You never receive any medssagea directly to you evem though your computer would recognise IPv4x. It would be a clusterfuck.
- billpg 7mo ago
  Your local machine isn't on the IPv4 internet if it doesn't have a globally routable IPv4 address. Your home router that sits on the end of a single IPv4 address would need to know about IPv4x, but in this parallel world you'd buy a router that does.
  - kolinko 7mo ago
    Of course you are, just behind NAT. If your device has it's own public IPv4 address then you don't need IPv4x, IPv6 or whatever else.
  - zadikian 7mo ago
    "all routers on your subnet need to understand that" I thought that meant the same thing you said
- digitalPhonix 7mo ago
  How would anything on the internet know about x.x.x.x.y.y…? Your computer knows it’s connected to an old router because dhcp gave it x.x.x.x address and not x.x.x.x... so it knows it’s running in old v4 mode. And it can still send outbound to a v4x address that it knows about.

theamk 7mo ago

you are missing the point - updating "network elements" was never the problem. Linux kernel has IPv6 support since 2.6. RedHat got IPv6 in 2008. Nginx got it in 2010. And yet there plenty of IPv4-systems out there. why? Software updates scale _very well_ - once author updates, all users get the latest version. The important part is sysadmin time and config files - _those_ don't scale at all, and someone needs to invest effort in every single system out there. That's where IPv6 really dropped the ball by having dual-stack the default. In IPv4x, there is no dual-stack. I upgrade my OS, and suddenly I can use IPv4x addresses... but I don't have to - all my configs are still valid, and if my router is not compatible, all devices still fall back to IPv4-compatible short addresses, but are using IPv4x stack. I upgrade the home router and suddenly some devices get IPv4x address... but it is all transparent to me - my router's NAT takes care of that if my upstream (ISP) or a client device are not IPv4x-capable. I have my small office network which is on the mix IPv4 and IPv4x addresses. Most Windows/Linux machines are on IPv4x, but that old network printer and security controller still have IPv4 address (with router translating responses). It still all works together. There is only one firewall rule set, there is only one monitoring tool, etc... My ACL list on NAS server has mix of IPv4 and IPv4x in the same list... So this is a very stark contrast to IPv6 mess, where you have to bring up a whole parallel network, setup a second router config, set up a separate firewall set, make a second parallel set of addresses, basically setup a whole separate network - just to be able to bring up a single IPv6 device. (Funny enough, I bet one _could_ accelerate IPv6 deployment a lot by have a standard that _requires_ 6to4/4to6/NAT64 technology in each IPv6 network... but instead the IPv6 supporters went into all-or-nothing approach)

billpg 7mo ago
"I bet one _could_ accelerate IPv6 deployment a lot by have a standard ..." ahem https://owl.billpg.com/sixgate/ https://owl.billpg.com/sixgate/
- theamk 7mo ago
  "The good thing about standards is that there are so many to choose from."
7mo ago

Animats 7mo ago

If you put part of the address in the body space, you can't encrypt the entire body. IPv6 adoption has been linear for the last two decades. Currently, 48% of Google traffic is IPv6.[1] It was 30% in 2020. That's low, because Google is blocked in China. Google sees China as 6% IPv6, but China is really around 77%. Sometimes it takes a long time to convert infrastructure. Half the Northeast Corridor track is still on 25Hz. There's still some 40Hz power around Niagara Falls. San Francisco got rid of the last PG&E DC service a few years ago. It took from 1948 to 1994 to convert all US freight rail stock to roller bearings.[2] European freight rail is still using couplers obsolete and illegal in the US since 1900. (There's an effort underway to fix this. Hopefully it will go better than Eurocoupler from the 1980s. Passenger rail uses completely different couplers, and doesn't uncouple much.)[3] [1] https://www.google.com/intl/en/ipv6/statistics.html https://www.google.com/intl/en/ipv6/statistics.html [2] https://www.youtube.com/watch?v=R-1EZ6K7bpQ https://www.youtube.com/watch?v=R-1EZ6K7bpQ [2] https://rail-research.europa.eu/european-dac-delivery-programme/ https://rail-research.europa.eu/european-dac-delivery-progra...

riffic 7mo ago
should also bring to mind that there's a technological leapfrogging effect in stages of development which it seems clear that China has taken advantage of. https://en.wikipedia.org/wiki/Leapfrogging https://en.wikipedia.org/wiki/Leapfrogging

deleted 7mo ago

[deleted]