Some Notes from Fixing my Server’s IPv6 / SLAAC

I had a hard time getting IPv6 to work properly on my VPS. It has a static address, which I published to DNS (ages ago), but it wasn’t fully operational. It wasn’t obvious, because it was able to accept and respond to incoming IPv6, but it was not able to generate outgoing IPv6 connections. Thanks to Happy Eyeballs, the system cheerfully fell back to IPv4 and left me none the wiser.  Probably for years. (Since inbound traffic could be responded to, the IPv6 network-transfer graph looked plausible, too.)