5 ms·

This post is from 2002. Was just a proposal that never took off? Is this something that was implemented and in active use? Trying to figure out if this is valua

This post is from 2002. Was just a proposal that never took off? Is this something that was implemented and in active use? Trying to figure out if this is valuable information about how the Internet works or if it’s a curiosity/novelty of the painful long road to IPv6.

zamadatix 7y ago
Dual stack (run both and try to use v6 first) and NAT64 (run IPv6 only and NAT to v4 at the edge) are the main methods today. The former is more common inside homes/enterprises while the latter is more common in modern large carrier networks such as mobile phones since the alternative would be to CGNAT (double NAT) anyways and that creates more problems for clients than NAT64 (+more work to deploy). Not to say CGNAT is unheard of, particularly if the network was large, old, and needed to expand.
- commandersaki 7y ago
  How do v4 clients (dual stacked) connected to the Internet with v4 talk to a v6 server?
  - dahfizz 7y ago
    Some v6 networks are able to convert your v4 to a v6 address, but that's pretty spotty. If you are v4 only, and the server is v6 only, you really don't have much hope of connecting.
    - commandersaki 7y ago
      And so we must rely on v4 addresses to cater for v4 only connected hosts. This is the point the article is trying to make - for a transition to actually happen there needs to be interoperability between v4 and v6, that is v4-only clients need to talk to v6-only servers, and v6-only servers need to talk to v4-only clients. That is a fundamental requirement for a transition plan which provides a straight-forward path from v4 to v6.
      - snuxoll 7y ago
        Which is dual-stack with a grandual phaseout of v4. We already pay for the bloat of the v4 routing tables, but nobody can even think of phasing them out until stuff actually starts using v6. But nobody wants to deploy v6 because everyone has this mistaken belief that it’s easier to stretch v4 out with more hacks to preserve addresses.
      - dahfizz 7y ago
        v4 only hosts are rarer than you would think. ISPs have been dual stacking for a while.
        commandersaki 7y ago
        The Internet is mostly v4-only. What do you mean?
        dahfizz 7y ago
        Do you have anything to back that up? I work in the Telco industry. The vast majority of ISPs and carriers both provide dual stacking at least, with some carriers making as much of their network v6 only. Really the only thing that is largely stuck on v4 is large (and poorly maintained) corporate networks and cloud providers.
        commandersaki 7y ago
        As I stated earlier v4 only means a network connected to the Internet via v4 without connectivity to v6. This is the majority of networks on the Internet. Otherwise we’d see adoption greater than 20% or whatever it is.
        h1d 7y ago
        My cloud servers from major players all have v6 address attached on launch.
  - zamadatix 7y ago
    There are multiple types of NAT which are simply named after what it is they NAT: - NAT44 (what everyone is used to) - NAT64 (what I just described) - NAT46 (the opposite of what I just described) - NAT66 (bad) In this case NAT46.
- xfalcox 7y ago
  CGNAT is default in our largest home ISP and on all mobile ISPs here in Brazil.
tzakrajs 7y ago
It's just a novelty, as my sibling comment mentions, nat64 and dual stacking allows you do everything you need. Nat64 requires a static route added to your gateway or each node, requires a custom DNS resolver and a daemon which manages iptables on a secondary gateway host for rewriting packets to/from IPv4 destination. It's pretty clever since it uses a /96 (32-bits) on the secondary gateway to return AAAA record for all IPv4 addresses. Dual Stack is more straight forward requiring only an additional IPv6 address to be allocated to each machine requiring access.
- commandersaki 7y ago
  Someone suggested the same thing. I'll ask the same question: How do v4 clients (dual stacked) connected to the Internet with v4 talk to a v6 server?
  - jcranmer 7y ago
    A IPv4-only client cannot talk to a IPv6-only server: a 128-bit address does not fit in a 32-bit address. In a dual-stacked network, you get an IPv4 and an IPv6 address, and the network speaks both IPv4 and IPv6. So you speak IPv6 to IPv6 servers and IPv4 to IPv4 servers. NAT64 has your ISP be an IPv6-only network--you get an IPv6, no IPv4 address--and your gateway to the Internet is an IPv4 server that translates public IPv4 addresses to IPv6 addresses for you to talk to. The server at that IPv6 address translates the IPv6 address you requested into the original IPv4 address, and acts as an IPv4 client to the IPv4 server.
    - commandersaki 7y ago
      (First I want to make a point/clarification. When I say v4-only, I mean a dual stacked host connected to Internet only via v4. Likewise for v6.) If you don't have v4 and v6 interoperability - that is v4-only cannot connect to v6-only and vice-versa, how does the Internet (mostly v4-only hosts) go to v6?
      - snuxoll 7y ago

zamadatix 7y ago

Dual stack (run both and try to use v6 first) and NAT64 (run IPv6 only and NAT to v4 at the edge) are the main methods today. The former is more common inside homes/enterprises while the latter is more common in modern large carrier networks such as mobile phones since the alternative would be to CGNAT (double NAT) anyways and that creates more problems for clients than NAT64 (+more work to deploy). Not to say CGNAT is unheard of, particularly if the network was large, old, and needed to expand.

commandersaki 7y ago
How do v4 clients (dual stacked) connected to the Internet with v4 talk to a v6 server?
- dahfizz 7y ago
  Some v6 networks are able to convert your v4 to a v6 address, but that's pretty spotty. If you are v4 only, and the server is v6 only, you really don't have much hope of connecting.
  - commandersaki 7y ago
    And so we must rely on v4 addresses to cater for v4 only connected hosts. This is the point the article is trying to make - for a transition to actually happen there needs to be interoperability between v4 and v6, that is v4-only clients need to talk to v6-only servers, and v6-only servers need to talk to v4-only clients. That is a fundamental requirement for a transition plan which provides a straight-forward path from v4 to v6.
    - snuxoll 7y ago
      Which is dual-stack with a grandual phaseout of v4. We already pay for the bloat of the v4 routing tables, but nobody can even think of phasing them out until stuff actually starts using v6. But nobody wants to deploy v6 because everyone has this mistaken belief that it’s easier to stretch v4 out with more hacks to preserve addresses.
    - dahfizz 7y ago
      v4 only hosts are rarer than you would think. ISPs have been dual stacking for a while.
      - commandersaki 7y ago
        The Internet is mostly v4-only. What do you mean?
        dahfizz 7y ago
        Do you have anything to back that up? I work in the Telco industry. The vast majority of ISPs and carriers both provide dual stacking at least, with some carriers making as much of their network v6 only. Really the only thing that is largely stuck on v4 is large (and poorly maintained) corporate networks and cloud providers.
        commandersaki 7y ago
        As I stated earlier v4 only means a network connected to the Internet via v4 without connectivity to v6. This is the majority of networks on the Internet. Otherwise we’d see adoption greater than 20% or whatever it is.
        h1d 7y ago
        My cloud servers from major players all have v6 address attached on launch.
- zamadatix 7y ago
  There are multiple types of NAT which are simply named after what it is they NAT: - NAT44 (what everyone is used to) - NAT64 (what I just described) - NAT46 (the opposite of what I just described) - NAT66 (bad) In this case NAT46.
xfalcox 7y ago
CGNAT is default in our largest home ISP and on all mobile ISPs here in Brazil.

tzakrajs 7y ago

It's just a novelty, as my sibling comment mentions, nat64 and dual stacking allows you do everything you need. Nat64 requires a static route added to your gateway or each node, requires a custom DNS resolver and a daemon which manages iptables on a secondary gateway host for rewriting packets to/from IPv4 destination. It's pretty clever since it uses a /96 (32-bits) on the secondary gateway to return AAAA record for all IPv4 addresses. Dual Stack is more straight forward requiring only an additional IPv6 address to be allocated to each machine requiring access.

commandersaki 7y ago
Someone suggested the same thing. I'll ask the same question: How do v4 clients (dual stacked) connected to the Internet with v4 talk to a v6 server?
- jcranmer 7y ago
  A IPv4-only client cannot talk to a IPv6-only server: a 128-bit address does not fit in a 32-bit address. In a dual-stacked network, you get an IPv4 and an IPv6 address, and the network speaks both IPv4 and IPv6. So you speak IPv6 to IPv6 servers and IPv4 to IPv4 servers. NAT64 has your ISP be an IPv6-only network--you get an IPv6, no IPv4 address--and your gateway to the Internet is an IPv4 server that translates public IPv4 addresses to IPv6 addresses for you to talk to. The server at that IPv6 address translates the IPv6 address you requested into the original IPv4 address, and acts as an IPv4 client to the IPv4 server.
  - commandersaki 7y ago
    (First I want to make a point/clarification. When I say v4-only, I mean a dual stacked host connected to Internet only via v4. Likewise for v6.) If you don't have v4 and v6 interoperability - that is v4-only cannot connect to v6-only and vice-versa, how does the Internet (mostly v4-only hosts) go to v6?
    - snuxoll 7y ago