alt Hacker News> backwards compatible with existing hardware/software
Absolutely not. Existing IPv4 hardware and software expects addresses to be 4 bytes long. They expect packets to have a 4 byte source address at offset 12 in the header, then a 4 byte destination address at offset 16. Everything breaks if you try to give them a header with an 8 byte source address at offset 12 and an 8 byte destination address at offset 20.
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For every complex and difficult problem, someone has an easy, simple and wrong solution. Usually the presence of "just" is a good clue.
The set of all ip hardware and software is much much larger than just what currently exists, as it includes all hardware and software that is yet to be produced. Said another way, it’s a foolish consistency.
> Absolutely not. Existing IPv4 hardware and software expects addresses to be 4 bytes long.
As does DNS.
"A" records are fixed at 32 bits, so you have to add a new record type and update all DNS software, plus user-space API/library code and data structures to ask for and store the new record type.
Just like IPv6.
There is no "just" adding more addresses: whatever scheme anyone comes up with is the same amount of work as IPv6.
* https://github.com/becarpenter/misc/blob/main/why6why.md