8 ms·

Another person who does not understand IPv4. IPv4 isn't a text based protocol where IP addresses are parsed like DNS. It's a binary protocol where addresses ar

Another person who does not understand IPv4. IPv4 isn't a text based protocol where IP addresses are parsed like DNS. It's a binary protocol where addresses are recorded in binary and adding more address space WOULD BE A BREAKING CHANGE.

schroeding 3y ago
For a practical demonstration: That's the reason decimal IPs work, too - i.e. http://3520653007/ http://3520653007/ is the same as http://209.216.230.207/ http://209.216.230.207/ (and both will go to HN) - it's all just nice formating for our human brains. Nothing would stop us from formatting IPv6 the IPv4 way except the monstrous length of the resulting address.
- TrickyRick 3y ago
  Wow learned something new today. What's interesting is that the decimal representation looks more like a phone number which people would be used to. Interesting that IP addresses as they are written today was the format that won, as a kid before learning how computers worked I always found it weird how 255 was the highest number in each group.
  - vel0city 3y ago
    Its often challenging enough for people to do CIDR subnet calculations in their head when its broken out into octets. I'd have just given up on networking entirely if the standard was to use decimal notation.
- ale42 3y ago
  You can even make it funnier by having it look like a floating point number: http://209.14214863/ http://209.14214863/ Or a strange number with two decimal parts: http://209.216.59087/ http://209.216.59087/
- bilekas 3y ago
  My whole life I went without knowing decimal IPs were a thing..
  - bombcar 3y ago
    There's more than just decimal .... https://daniel.haxx.se/blog/2021/04/19/curl-those-funny-ipv4-addresses/ https://daniel.haxx.se/blog/2021/04/19/curl-those-funny-ipv4...
  - patmorgan23 3y ago
    A 32-bit number is a 32-bit number. Whether you represent it in dot notation, hex or decimal.
bmacho 3y ago
That's not what GP said. Of course IPv4 devices wouldn't be able to use IPv6 addresses, that would be impossible. But it is possible to "keep" IPv4 addresses, just make a.b.c.d to correspond 0.0.a.b.c.d.
- deleted 3y ago
  [deleted]
- ffomni 3y ago
  First of all, the 4 in IPv4 has nothing to do with its addresses typically being represented in dotted 4-octett notation. That's a coincidence. Each address is a 32 bit number, that's it. Early versions of IPv4 as well as some of the experimental IPv3 drafts actually used 128 bits. In IPv6 there are 128 bits for each address. Nothing to do with 6, which is just a version number. Second, IPv6 is not just about addressing, it's a new protocol. Many things are different in IPv6, lots make much more sense. The header structure is different. Etc etc. The address space and notation are just the most visible aspects. But it's like comparing IRC and Signal. It's not just about user names, it's a different protocol. Third, there are embeddings of the IPv4 address space into the IPv6 address space. For example ::ffff:192.0.2.128. Note the mix in notation. This is a valid IPv6 address! Perhaps a bit more cumbersome to write than your suggestion, but for technical reasons it was preferred to keep things syntactically unambiguous (that it's an IPv6 address). Source: I work at a large router vendor, in the routing team. Also, none of this is secret. Just read the Wikipedia page. I'm slightly shocked how a tech forum supposedly full of hackers is posting so much half truths and plain wrong information. It's all easily available and understandable, and it's not like we're discussing neurosurgery or epidemiology where we're all amateurs.
  - bmacho 3y ago
    You and Plasmoid completely misunderstood dheera and me. I failed to clarify this misunderstanding explicitly (I still don't see where does it come from), so I do it now. > I grew up with IPv4 (1.2.3.4) and I was expecting IPv6 to just be 1.2.3.4.5.6 with backward compatibility so that 1.2.3.4 would just be 0.0.1.2.3.4 and the 1.2.3.4 dude wouldn't need to change their address. As you can see, dheera did not state that IPv4 or IPv6 work with strings. They just said that they wished/expected the trivial extension of the IPv4 protocol, with the same notation, and preserving the existing IPv4 addresses. (These are 2 distinct wishes.) Acknowledging that this did not happen. Nor dheera nor me posted any half truth or plain wrong information.
mike_d 3y ago
Not at all. We could have taken one of the unassigned /8's at the time and allocated it to v6 transitional addressing (the failure to address 4->6 reachability is IMO why v6 failed). For the sake of this example lets use 53.0.0.0/8. All new addresses start with 00110101 followed by the first three bytes of the new v6 prefix. The prefix acts as a flag that indicates it is a new address and routers read an additional 5 bytes from the beginning of what would be the data section of a traditional v4 packet to get the complete address. Now your border router can announce your assigned transitional prefix, i.e. 53.32.122.91/32, and is responsible for routing packets to a NAT gateway that knows both v4 and v6 and rewrites packets seamlessly each way. What we are left with is a scheme that allows v6 to exist on top of v4 and continue working across the existing internet, and the only people who need to worry about it or upgrade anything are the ones who need more address space. But instead they followed the model of baking in every stakeholders random pet project into v6 to get consensus in the hopes of forcing adoption. They put letters in the middle of numbers, and expected us to not hate it like algebra.
- deleted 3y ago
  [deleted]
- Denvercoder9 3y ago
  > They put letters in the middle of numbers If you prefer, you could write an IPv6 address in dotted-decimal notation just like an IPv4 address, or an IPv4 in hexadecimal notation like an IPv6 address. It's just 128 (IPv6) or 32 (IPv4) bits of data after all, the representation is completely independent of the protocol. For example, you can also reach HN through its IPv4 address by writing http://3520653007/ http://3520653007/ or http://0xD1D8E6CF/ http://0xD1D8E6CF/.
- cesarb 3y ago
  > The prefix acts as a flag that indicates it is a new address and routers read an additional 5 bytes from the beginning of what would be the data section of a traditional v4 packet to get the complete address. Your proposal, as usual for these kinds of proposals, fails to consider how would an "old world" endpoint talk to a "new world" endpoint. An "old world" endpoint wouldn't know about these "additional 5 bytes", and would both send packets without them to "new world" endpoints (confusing them) and treat them as data bytes when receiving from "new world" endpoints. The only solution would be to upgrade all the computers on the "old world" first, but once you have to do that you could move them all to the "new world" instead. If what you want is just the addressing (for instance, you already have 192.0.2.1, and want to use it for IPv6 without needing to obtain an IPv6 address first), there's already 6to4, which has most of the properties you want: it exists on top of IPv4, your router announces the IPv4 prefix, and IPv6 packets sent to it are transparently routed to a relay router which encapsulates them inside IPv4 packets destined to that IPv4 address (in the other direction, your encapsulated packets are sent to a relay router which extracts the IPv6 packet and forwards it). I've used this in the past to give full IPv6 connectivity to a site which had only a single IPv4 address, and it worked well.

schroeding 3y ago

For a practical demonstration: That's the reason decimal IPs work, too - i.e. http://3520653007/ http://3520653007/ is the same as http://209.216.230.207/ http://209.216.230.207/ (and both will go to HN) - it's all just nice formating for our human brains. Nothing would stop us from formatting IPv6 the IPv4 way except the monstrous length of the resulting address.

TrickyRick 3y ago
Wow learned something new today. What's interesting is that the decimal representation looks more like a phone number which people would be used to. Interesting that IP addresses as they are written today was the format that won, as a kid before learning how computers worked I always found it weird how 255 was the highest number in each group.
- vel0city 3y ago
  Its often challenging enough for people to do CIDR subnet calculations in their head when its broken out into octets. I'd have just given up on networking entirely if the standard was to use decimal notation.
ale42 3y ago
You can even make it funnier by having it look like a floating point number: http://209.14214863/ http://209.14214863/ Or a strange number with two decimal parts: http://209.216.59087/ http://209.216.59087/
bilekas 3y ago
My whole life I went without knowing decimal IPs were a thing..
- bombcar 3y ago
  There's more than just decimal .... https://daniel.haxx.se/blog/2021/04/19/curl-those-funny-ipv4-addresses/ https://daniel.haxx.se/blog/2021/04/19/curl-those-funny-ipv4...
- patmorgan23 3y ago
  A 32-bit number is a 32-bit number. Whether you represent it in dot notation, hex or decimal.

bmacho 3y ago

That's not what GP said. Of course IPv4 devices wouldn't be able to use IPv6 addresses, that would be impossible. But it is possible to "keep" IPv4 addresses, just make a.b.c.d to correspond 0.0.a.b.c.d.

deleted 3y ago
[deleted]
ffomni 3y ago
First of all, the 4 in IPv4 has nothing to do with its addresses typically being represented in dotted 4-octett notation. That's a coincidence. Each address is a 32 bit number, that's it. Early versions of IPv4 as well as some of the experimental IPv3 drafts actually used 128 bits. In IPv6 there are 128 bits for each address. Nothing to do with 6, which is just a version number. Second, IPv6 is not just about addressing, it's a new protocol. Many things are different in IPv6, lots make much more sense. The header structure is different. Etc etc. The address space and notation are just the most visible aspects. But it's like comparing IRC and Signal. It's not just about user names, it's a different protocol. Third, there are embeddings of the IPv4 address space into the IPv6 address space. For example ::ffff:192.0.2.128. Note the mix in notation. This is a valid IPv6 address! Perhaps a bit more cumbersome to write than your suggestion, but for technical reasons it was preferred to keep things syntactically unambiguous (that it's an IPv6 address). Source: I work at a large router vendor, in the routing team. Also, none of this is secret. Just read the Wikipedia page. I'm slightly shocked how a tech forum supposedly full of hackers is posting so much half truths and plain wrong information. It's all easily available and understandable, and it's not like we're discussing neurosurgery or epidemiology where we're all amateurs.
- bmacho 3y ago
  You and Plasmoid completely misunderstood dheera and me. I failed to clarify this misunderstanding explicitly (I still don't see where does it come from), so I do it now. > I grew up with IPv4 (1.2.3.4) and I was expecting IPv6 to just be 1.2.3.4.5.6 with backward compatibility so that 1.2.3.4 would just be 0.0.1.2.3.4 and the 1.2.3.4 dude wouldn't need to change their address. As you can see, dheera did not state that IPv4 or IPv6 work with strings. They just said that they wished/expected the trivial extension of the IPv4 protocol, with the same notation, and preserving the existing IPv4 addresses. (These are 2 distinct wishes.) Acknowledging that this did not happen. Nor dheera nor me posted any half truth or plain wrong information.

mike_d 3y ago

Not at all. We could have taken one of the unassigned /8's at the time and allocated it to v6 transitional addressing (the failure to address 4->6 reachability is IMO why v6 failed). For the sake of this example lets use 53.0.0.0/8. All new addresses start with 00110101 followed by the first three bytes of the new v6 prefix. The prefix acts as a flag that indicates it is a new address and routers read an additional 5 bytes from the beginning of what would be the data section of a traditional v4 packet to get the complete address. Now your border router can announce your assigned transitional prefix, i.e. 53.32.122.91/32, and is responsible for routing packets to a NAT gateway that knows both v4 and v6 and rewrites packets seamlessly each way. What we are left with is a scheme that allows v6 to exist on top of v4 and continue working across the existing internet, and the only people who need to worry about it or upgrade anything are the ones who need more address space. But instead they followed the model of baking in every stakeholders random pet project into v6 to get consensus in the hopes of forcing adoption. They put letters in the middle of numbers, and expected us to not hate it like algebra.

deleted 3y ago
[deleted]
Denvercoder9 3y ago
> They put letters in the middle of numbers If you prefer, you could write an IPv6 address in dotted-decimal notation just like an IPv4 address, or an IPv4 in hexadecimal notation like an IPv6 address. It's just 128 (IPv6) or 32 (IPv4) bits of data after all, the representation is completely independent of the protocol. For example, you can also reach HN through its IPv4 address by writing http://3520653007/ http://3520653007/ or http://0xD1D8E6CF/ http://0xD1D8E6CF/.
cesarb 3y ago
> The prefix acts as a flag that indicates it is a new address and routers read an additional 5 bytes from the beginning of what would be the data section of a traditional v4 packet to get the complete address. Your proposal, as usual for these kinds of proposals, fails to consider how would an "old world" endpoint talk to a "new world" endpoint. An "old world" endpoint wouldn't know about these "additional 5 bytes", and would both send packets without them to "new world" endpoints (confusing them) and treat them as data bytes when receiving from "new world" endpoints. The only solution would be to upgrade all the computers on the "old world" first, but once you have to do that you could move them all to the "new world" instead. If what you want is just the addressing (for instance, you already have 192.0.2.1, and want to use it for IPv6 without needing to obtain an IPv6 address first), there's already 6to4, which has most of the properties you want: it exists on top of IPv4, your router announces the IPv4 prefix, and IPv6 packets sent to it are transparently routed to a relay router which encapsulates them inside IPv4 packets destined to that IPv4 address (in the other direction, your encapsulated packets are sent to a relay router which extracts the IPv6 packet and forwards it). I've used this in the past to give full IPv6 connectivity to a site which had only a single IPv4 address, and it worked well.