Protocols

I use a little Chrome extension called IPvFoo which tells me which protocols a page is using; over the weekend I noticed that connections to Facebook and Youtube were always IPv4, usually they're IPv6. Everything else that could connect with IPv6 was doing so, so I assumed it wasn't me or my ISP.

Today they're back to normal. It seems reasonable to me that both would have been very busy over the weekend so maybe IPv6 was feeling the squeeze in some way, and I've seen the same happen occasionally in the (usually early) evenings.

But I didn't really expect the choice of protocols to be traffic sensitive... is it?

I should have added that sometimes when opening a page there would be a brief (<< 1 second) flash of a "6", then it would go to a "4" and stay that way, as though the site was doing some sort of redirect?

https://en.wikipedia.org/wiki/Happy_Eyeballs

When you are loading Facebook you aren’t making a single request to a single webserver. You’ll be fetching multiple resources from across a set of webservers.

So it is perfectly possible for some of them to be being routed via IPv6 and others via IPv4 without any sort of redirect occurring.

jpm beat me to it, but google introduced a new RFC called happy eyeballs, in the past IPv6 was prioritised and it still is in most operating systems, but chrome based browsers override this behaviour and the browser will query both stacks, and the one that responds first is used. I am not aware of a way to change this via any setting on chrome, they hard coded it in.

If you use something like Firefox you will get the older expected behaviour.

Edited by Chrysalis (Wed 26-Jun-24 01:04:36)

I knew about the Happy Eyeballs, but I'd forgotten it... thanks for the reminders

(I thought I'd already responded to this thread, seems I didn't press the final "Continue" )

In reply to a post by billford:

I knew about the Happy Eyeballs, but I'd forgotten it... thanks for the reminders

Of course there's one way to guarantee IPv6: no A record. I use such a configuration on private URLs, but unless you are a "Loops of Zen" fan it's not going to be seen in the wild too often.

Could be maintenance or something else on peering connections or in provider's network. Also if for some reason performance over v6 was worse (routing could be different) it may have reverted to v4..