Hello there. I need help with MariaDB database to be available to all my applications from multiple destinations. It means I have a desktop application with a connection string to MariaDB database. The problem is, my server refuses the connection.
I have another instance that works for years now. Unfortunately, I don’t know how to make it work on my new VPS. I want to migrate a database to a new server. In these 3 years, many have changed 
Instead of MySQL now i have MariaDB. I believe that is not the reason I can’t get to my data.
What to consider, and how to make this all secure? If there is someone to give me guidelines. I believe the firewall gives me a headache. I’m not quite sure, but it looks like the firewall won’t let my connection. Besides FirewallD, is there any other firewall I need to set up?