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Comment by MagicMoonlight | Hacker News Reader

I still don't get why we can't just expand IPv4 into IPv5 by adding some new blocks to the front.

So instead of 192.0.0.1 it becomes 0.0.0.0.192.0.0.1

All existing addresses work, you simply append zeroes to any address which is too short for the new standard. Any old timey software still works as long as you use a router between the two systems with an old timey address.

This would give us as many addresses as we want without any changes or downsides. So why no do?

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IP is not a text format (like HTTP). It's a binary format where each field of the IPv4 header has an exactly defined offset and length. The source IP address is placed at offset 96 and has a length of 32 bit, the destination IP address sits right afterwards with the same length. Changing anything will result in new protocol definition, et voilà that's IPv6.

https://en.wikipedia.org/wiki/Internet_Protocol_version_4#He...

In addition, there are also impacts on other protocols such as ARP, DHCP, ICMP, DNS etc.

So it's not as simple as changing only the IP packet format either.

This comment is just HN at its best. Chef's kiss. The Internet Engineering Task Force, a group of experts in the field, spent years and countless hours creating a new standard, but do not let that stop us from napkin-sketching up a new solution ourselves, I mean how smart can these experts really be?

I wish I had the ability to downvote, so I could downvote this comment into oblivion. What a shit attitude to have. Asking stupid questions is how you learn. You stop asking questions, you stop learning.

That's way too logical. Have some respect for the artisanal bike shedding that went into IPv6!

Calling it IPv5 is genius though.

IP version 5 actually was a real thing[0] (though it's usually called "Internet Stream Protocol"). It still used 32-bit addresses though.

[0]: https://en.wikipedia.org/wiki/Internet_Stream_Protocol

I guess because it's not simply a text address, it's a protocol where a specific number of bytes in the packet (4 in this case) are dedicated for IP, you can't just simply modify this.

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