[labcomputer]

> IPv4 is not variable-length.

I get the impression that this fact is fundamentally lost on a lot of the people who want a "compatible" IPv6. Like, their mental model does not distinguish between how we as humans write down an IPv4 address in text and how that address is represented in the packet.

So they think "let's just add a couple more dots and numerals and keep everything else the same"

[kstrauser]

I think you’re right. Honestly, my impression is that a lot of people imagine it like a string field, and others more like a rich text field, analogous to “can’t we just use a smaller font?”