.INTERNAL is now reserved for private-use applications

My biggest frustration with .internal is that it requires a private certificate authority. Lots of organizations struggle to fully set up trust for the private CA on all internal systems. When you add BYOD or contractor systems, it's a mess.

Using a publicly valid domain offers a number of benefits, like being able to use a free public CA like Lets Encrypt. Every machine will trust your internal certificates out of the box, so there is minimal toil.

Last year I built getlocalcert [1] as a free way to automate this approach. It allows you to register a subdomain, publish TXT records for ACME DNS certificate validation, and use your own internal DNS server for all private use.

[1] https://www.getlocalcert.net/

The problem with internal CAs is also that it's really hard to add them on some OSes now. Especially on android since version 7 IIRC, you can no longer get certs into the system store, and every app is free to ignore the user store (I think it was even the default to ignore it). So a lot of apps will not work with it.

Speculating a bit out of my depth here, but I'm under the impression that most of those sometimes-configurable OS-level CA lists are treated as "trust anything consistent with this data", as opposed to "only trust this CA record for these specific domain-patterns because that's the narrow purpose I chose to install it for."

So there are a bunch of cases where we only want the second (simpler, lower-risk) case, but we have to incur all the annoyance and risk and locked-down-ness of the first use-case.