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?
If you can disable IPv4 on sshd then it really isn’t an issue. I know, security through obscurity isn’t robust, but when I had sshd with IPv4 enabled, I was getting around 6 - 10 failed login attempts a minute. People iterate through all the IPv4 addresses since there are only 4,294,967,296 possible addresses. There are 340,282,366,920,938,463,463,374,607,431,768,211,456 possible IPv6 addresses, so the chance of someone randomly stumbling upon your address is fucking astronomically tiny. When I disabled IPv4 a couple years ago I’ve had exactly zero failed logins that weren’t me being a sloppy typist.