I migrated 40 customer WordPress sites to IPv6-only at Vultr last month. 3 broke immediately due to plugins calling external APIs with hardcoded IPv4. One was a popular SEO plugin checking Google PageSpeed. Another was a contact form using reCAPTCHA v2.
I rolled back 2 of them. The third I fixed with a tiny NAT64 I run on a 2 USD instance. Not proud but it works.
Google finally added v6 support to reCAPTCHA enterprise but not the free tier. Typical.
My list from earlier was missing one: Steam game servers. You can browse the store over v6 but multiplayer matchmaking often fails. Valve says "use Steam Datagram Relay" which is v4 wrapped.
Future is here but wrapped in v4.
Same here on the Steam thing. Also Discord voice channels. Text works, voice needs the v4 fallback for "some regions" according to their status page.
This thread should be a wiki actually.
Wiki would be good. I found another: the Python requests library with default settings on Ubuntu 22.04 tries AAAA first but if it gets any response it does not fallback to A on timeout. This is not IPv6's fault but it breaks things. Fixed in requests 2.32 apparently.
I spent 4 hours on this.
Is there a summary of what was settled? I want to try IPv6-only at HostHatch but not sure if I need the tunnel from start or can add later.
Short version: you need the tunnel from start or you will be debugging at 2 AM. Hetzner is cheapest. WireGuard is easiest. Docker needs daemon.json flag. DNS needs checking. Everything else you discover as you go.
Welcome to the experiment.
