If it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck.

But it has to look, swim, and quack like a duck. If it only does one or two, it might be something else entirely.

Almost two years ago I opened a ticket on GitHub because I couldn’t (and still can’t) install packages via pip on an IPv6-only host with an IPv6-only resolver. Fastly is used as a CDN, and the authoritative DNS servers involved simply don’t have AAAA records. It’s just a matter of switching to a different set of DNS servers.

I recently looked at a curriculum for a basic level course of a well known vendor. What struck my eye was that IPv4 basics, including classes, was pretty high on the list of topics. Then I found stuff like RIP version 1 in the list of topics an IPv6 almost at the end of the list of topics.

My calendar says it’s the End of 2025 so IPv6 should be at least as important as IPv4. IPv4 classes should only be viewed in a historical context, same as RIPv1.

A short one, also via mastodon:

host deutschehochschule.de
deutschehochschule.de has address 162.159.134.42
deutschehochschule.de has IPv6 address ::ffff:162.159.134.42
deutschehochschule.de mail is handled by 0 deutschehochschule-de.mail.protection.outlook.com.

“Of course we have IPv6”. BTW: The IPv4 address is from Cloudflare. AFAIK: You have to actively do something not to do proper IPv6 using Cloudflare.

Some shameless advertising:

If you need some help with IPv6, DNS, Linux, Automation and related stuff feel free to contact me. I’m available for about two days a week, remote preferred.

Yet another Mastodon-inspired post. In this toot the author reports that downloading python packages is slow, and the Internet said that disabling IPv6 is the solution.

Slow can mean two different things here. If the host I’m using has a globally unique IPv6 address, but my connection to the outside is broken somehow, most software would try IPv6 first and then, after a timeout would fall back to IPv4 and try again. It can also mean that the IPv6 connection is working, but the download is actually slow.