Some services run really good behind a reverse proxy on 443, but some others can really become an hassle… And sometimes just opening other ports would be easier than to try configuring everything to work through 443.
An example that comes to my mind is SSH, yeah you can use SSLH to forward requests coming from 443 to 22, but it’s so much easier to just leave 22 open…
Now, for SSH, if you have certificate authentication or a strong password, I think you can feel quite safe, but what about other random ports? What risks I’m exposing my server to if I open some of them when needed for a service? Is the effort of trying to pass everything through 443/80 worth it?
Yes and no
Breaking out of docker in a real life context would require either a massive misconfiguration or a major security vulnerability. Chances are you aren’t going to have much in the way of lateral movement but it is always good to have defense in depth.
If someone’s self-hosting, I’d be willing to bet they don’t have the same hardened config or isolation that a cloud provider would.