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> Incidentally, "IPv8" proponents often ask why IPv6 didn't simply stick some extra bits on the front of IPv4 addresses, instead of inventing a whole new format

> Incidentally, "IPv8" proponents often ask why IPv6 didn't simply stick some extra bits on the front of IPv4 addresses, instead of inventing a whole new format. Actually, we tried that: the "IPv4-Compatible IPv6 address" format was defined in {{RFC3513}} but deprecated by {{RFC4291}} because it turned out to be of no practical use for coexistence or transition. Any tl;dr on why/how the simplest solution imaginable would have been "of no practical use for coexistence or transition"? Granted, I understand the other points make a strong enough case by themselves.

duskwuff 6mo ago
TL;DR: because it doesn't actually solve anything. Being able to jam an IPv4 address into an IPv6 packet header doesn't mean you can send that packet to an IPv4-only host and have it be understood. You still need an IPv6 stack on both endpoints, and on all the routers in the middle - and at that point, why not just use IPv6 addresses?
- direwolf20 6mo ago
  Also, it already exists. The IPv4 range is included in the IPv6 range. 0000:0000:0000:0000:0000:ffff:0a00:0001 is the official IPv6 representation of 10.0.0.1. As you can see, it doesn't actually solve anything. It makes some APIs more convenient! You can pass this address to Linux for an IPv6 socket and it will secretly open an IPv4 connection to 10.0.0.1, so your code only has to support IPv6 sockets to support IPv6 and IPv4 connections. It seems I've been rate limited to post every 12 hours, instead of five times per three hours. It must be either because I said interpreters don't emit native instructions, or because I said America had to buy TikTok to maintain American propaganda, or because I said you can make money gambling if your bets are the same as insiders. Or maybe I'm being punished for voting. I don't think dang will ever confirm what the reason was. Hacker News is so intransparent.

duskwuff 6mo ago

TL;DR: because it doesn't actually solve anything. Being able to jam an IPv4 address into an IPv6 packet header doesn't mean you can send that packet to an IPv4-only host and have it be understood. You still need an IPv6 stack on both endpoints, and on all the routers in the middle - and at that point, why not just use IPv6 addresses?

direwolf20 6mo ago
Also, it already exists. The IPv4 range is included in the IPv6 range. 0000:0000:0000:0000:0000:ffff:0a00:0001 is the official IPv6 representation of 10.0.0.1. As you can see, it doesn't actually solve anything. It makes some APIs more convenient! You can pass this address to Linux for an IPv6 socket and it will secretly open an IPv4 connection to 10.0.0.1, so your code only has to support IPv6 sockets to support IPv6 and IPv4 connections. It seems I've been rate limited to post every 12 hours, instead of five times per three hours. It must be either because I said interpreters don't emit native instructions, or because I said America had to buy TikTok to maintain American propaganda, or because I said you can make money gambling if your bets are the same as insiders. Or maybe I'm being punished for voting. I don't think dang will ever confirm what the reason was. Hacker News is so intransparent.