IPv6 is hard
Yesterday I read this toot (German) over on mastodon which starts with “IPv6 is hard.”
No it’s not. It’s different.
I ran across this multiple times: There is an A and an AAAA-record for a FQDN, but the web server is only reachable via IPv4. You can easily test this with curl
$ curl -4 https://github.com -o /dev/null % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 100 273k 0 273k 0 0 3417k 0 --:--:-- --:--:-- --:--:-- 3553k $ curl -6 https://github.