Comment by happyopossum
5 months ago
That’s not negotiating- I can’t connect to a server over v4 and have it tell me to switch to v6 or vice versa. That’s just supporting 2 completely different protocols.
5 months ago
That’s not negotiating- I can’t connect to a server over v4 and have it tell me to switch to v6 or vice versa. That’s just supporting 2 completely different protocols.
Right. The closest thing we have to IPv6 "negotiation" is the Happy Eyeballs algorithm[0], which is literally just "connect to both at the same time and pick the one that connects first". The name serves to legitimise it and make it sound fancy but it's basically just brute force + a bit of caching.
[0] https://en.wikipedia.org/wiki/Happy_Eyeballs