Pain points. Or, IPv6-only: the ugly bits

Alongside my tech nibbles posts, I'm going to add another type of short post which chronicles the difficulties I've encountered in trying to achieve my IPv6-only end state. These posts may contain somewhat spicy opinions 🌶️ or ranting 🤬.

Mostly I have worked through these problems, but documenting them is valuable for me in clarifying my thinking about these specific problems and problem solving in general, and obviously having the fixes explained is useful for others searching for solutions.

With pain points I'll still be aiming to keep the posts under 500 words, but there may be some slightly longer ones which include code snippets to keep things clear and practical.