Once I had Postgresql db with default password on a new vps, and forgetting to disable password based login, on a server with no domain. And it got hacked in a day, and was being used as bot server. And that was 10 years ago.

Recently deployed server, and was getting ssh login attempts within an hour, and it didn't had a domain. Fortunately, I've learned my lesson, and turned of password based login as soon as the server was up and running.

And similar attempts bogged down my desktop to halt.

Having an machine open to the world is now very scary. Thanks God for service like tailscale exists.