I know, that if I want I could run my application ( C++ or .NET ) , which I've developed internally. I mean, I have an external IP for my PC, but for the security reasons I don't want my application to be seen, so for it, I just set NOT an external IP for the part where I'm binding an IP for a socket, that listening. That is the way how I did my application be seen only internally.
But what for the MySQL server? I scanned my server and see, that MySQL 3306 port is seen. I think it's bad. How can I hide MySQL Server from the public and make it ineternally seen?