If only the news reporting was not as stupid as "internet is not working at UPC", instead of DNS resolvers at UPC crashed, here's what you can do...

Anyway, I didn't even notice since I run knot-resolver at home.

I wonder what it will be like connecting Facebook back to the internet, thundering herd and everything...

I suspect that the DNS aspect will be fine. The middle DNS servers only need one valid response to cache it for $TTL, but they can't cache SERVFAIL.

> but they can't cache SERVFAIL.

Correction: according to Cloudflare's blog post, some do cache errors as well.

I mean connecting your company to the internet when you have billions of devices waiting in the line to fetch updates, or whatever.

Will not that be an issue? Re-enabling routing to such a massive internet service...

I suspect it will slowly get there. We'll find out, it is recovering now.

Quite likely. Cloudflare has a report that outlines the reason behind it: https://blog.cloudflare.com/october-2021-facebook-outage/

Same in the UK, I've just experienced external DNS outage on BT!

All most people have to do now is install an app and it takes care. But messaging need to go from media and news.

Vodafone is down in Romania too.