They may block IP addresses associated with consumer ISPs. Assuming that’s the case, I would guess you’re seeing that as an HSTS/TLS error because their network is trying to trick your browser into redirecting to/displaying an error page hosted by some part of their network.

IMO, the best free option is https://freedns.afraid.org/. The biggest downside of that one is that you have to login a couple times a year (IIRC?) to keep it active. I actually still use this even though I have a paid domain, I just CNAME my real domains to the afraid dynamic name. That was easier than changing the config every time I become unhappy with my domain registrar and have to reconfigure everything after swapping.

Defense in depth. If something escapes the container it’s limited to only what’s under that user and not the whole system. Having access to the whole system makes it easier for malware to hide/persist itself.

If your distro offers it, rootless podman + podman system service is the best setup, IMO. That will give you a docker command that is 1-to-1 compatible with docker and lets you use tools like docker-compose that expect a docker service socket. Then you can just follow tutorials that only explain things for docker.

That’s not really possible with docker TBH, and I say that as a diehard Podman advocate. Docker, the tooling that you install with your package manager, is open source. Sure they have windows and mac desktop stuff that isn’t open, but it’s not like you’re self-hosting with that, right?

Plus there’s always Podman to switch to, which can be a (mostly) drop-in replacement, if you want something with a more trustworthy provenience.

Compose works with podman too, you just need podman system service & to set the DOCKER_HOST env var to it’s socket.