.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/

I don’t understand the frustration. The use of .internal is explicitly for when you don’t want a publicly valid domain. Nobody is forcing anyone to use .internal otherwise.

My frustration is because using a private CA is more difficult than it should be.

You can't just add the CA to system trust stores on each device, because some applications, notably browsers and java, use their own trust stores, you have to add it to.

You also can't scope the CA to just .internal, which means in a BYOD environment, you have to require your employees to trust you not to sign certs for other domains.

And then there is running the CA itself. Which is more difficult than using let's encrypt.

The Name Constraints extension can limit the applicability of a CA cert to certain subdomains or IP addresses.

How well supported is that?