You're picking a brief and vague 1-sentence summary he wrote, and missing everything that came after it that explained in detail what he's talking about.
> What else could he have meant with "In other words: The current IPv6 specifications don't allow public IPv6 addresses to send packets to public IPv4 addresses."
He could've meant "making IPv6 work means much more than upgrading software. Every administrator of a server on a public IPv4 address has to go to extra effort to acquire and enable a public IPv6 address."
You cannot read this and miss the fact that his frustration is with the need for administrators to acquire separate IPv6 addresses.
> maybe I should reread the article a bit more generously and less literally
No need to do either. Just read all of it, instead of 1 or 2 sentences that might sound like amateurish mistakes when you remove several pages of context and then extrapolate without them.
I have read all of it and I don't agree with you.
But lets roll with your interpretation.
Adding the address to the server is the easiest part of the whole process.
Upgrading the software is probably the biggest hurdle with people just hardcoding things to 32-bit left and right (and some badly designed APIs which do either IPv4 or IPv6 but not both in a transparent fashion).
And next is actually setting up ipv6 connectivity.
All those other things you would still have to take care of even if you magically could keep using the IPv4 address in IPv6 (however that would work).
Never mind that servers don't statically sit around forever, but one has to set up new servers all the time.
So why not go for the inverse approach for new servers?
Only give the servers IPv6 addresses and for those servers that still need to be reached via the public IPv4 internet (most internal ones probably have no need of this) can be accessed via SIIT, which performs stateless mapping between IPv4 and IPv6 (for example IPv4 1.2.3.4 gets translated to IPv6 2001:db8::1.2.3.4 and vice versa).
> Adding the address to the server is the easiest part of the whole process. Upgrading the software is probably the biggest hurdle with people just hardcoding things to 32-bit left and right (and some badly designed APIs which do either IPv4 or IPv6 but not both in a transparent fashion). And next is actually setting up ipv6 connectivity.
Funny, because the reality is that the software has for the most part been written and the hard part is acquiring v6 addresses. The problem is it isn't just a matter of acquiring a v6 address, it's also supporting the software that the v6 address runs on, and having it work the exact same way as v4.
The answer is that I'm actually talking about a huge number of IPv4 sites. There's nothing special about my site. When the same situation is repeated at N sites, the code is written only once, while the trivial requests and the trivial configuration changes are repeated N times.
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Well, I'm looking at a much larger group of users, and most of them aren't putting even five seconds into IPv6. They have better things to do. If the IPv6 configuration isn't automatic, it won't happen.
> So why not go for the inverse approach for new servers? Only give the servers IPv6 addresses and for those servers that still need to be reached via the public IPv4 internet (most internal ones probably have no need of this) can be accessed via SIIT, which performs stateless mapping between IPv4 and IPv6 (for example IPv4 1.2.3.4 gets translated to IPv6 2001:db8::1.2.3.4 and vice versa).
I'm unfamiliar with SIIT, but I bet it doesn't get us closer to the "magic moment" or we would be flocking to IPv6 addresses:
The magic moment for IPv6 will be the moment when people can start relying on public IPv6 addresses as replacements for public IPv4 addresses. That's the moment when the Internet will no longer be threatened by the IPv4 address crunch.
> I have read all of it and I don't agree with you. But lets roll with your interpretation.
You don't need to agree with me on what he's saying. The quote "...extra effort to acquire and enable a public IPv6 address" is a directly copied from his own page. It doesn't make sense to read that and claim that's not what he's saying, or to claim I'm "interpreting" it to mean that. That quote is what he's saying.
> even if you magically could keep using the IPv4 address in IPv6 (however that would work)
It's not magical, I explained it in [1]. And he himself started to explain it when he wrote "The specifications could have [...], but they didn't", but he didn't finish the thought, and just left the reader to figure out the rest of it. (Which, again, I explained in [1].)
> Adding the address to the server is the easiest part of the whole process.
The issue isn't "adding the address to the server". The issue is obtaining said address to be able to add it to the server in the first place. This requires both you and your ISP to set up and manage/maintain an entirely independent parallel network with an entirely separate configuration. It's an administrative hurdle, not merely a technical one. I can't explain it better than this user did, so just read his comment [2].
In any case, it's fine if you disagree that this is actually a significant hurdle; I'm not trying to argue that point. My goal here was to portray what djb is saying accurately, not to agree or disagree with it. So if you disagree with it, that's mission accomplished (for me anyway).
> What else could he have meant with "In other words: The current IPv6 specifications don't allow public IPv6 addresses to send packets to public IPv4 addresses."
He could've meant "making IPv6 work means much more than upgrading software. Every administrator of a server on a public IPv4 address has to go to extra effort to acquire and enable a public IPv6 address."
You cannot read this and miss the fact that his frustration is with the need for administrators to acquire separate IPv6 addresses.
> maybe I should reread the article a bit more generously and less literally
No need to do either. Just read all of it, instead of 1 or 2 sentences that might sound like amateurish mistakes when you remove several pages of context and then extrapolate without them.