Minecraft is a sandbox game developed by Mojang Studios and originally released in 2009. Minecraft is a 3D sandbox game that has no required goals to accomplish, allowing players a large amount of freedom in choosing how to play the game.

Multiplayer in Minecraft enables multiple players to interact and communicate with each other on a single world. It is available through direct game-to-game multiplayer, LAN play, local split screen (console-only), and servers (player-hosted and business-hosted).Players can run their own servers, use a hosting provider, or connect directly to another player's game via Xbox Live. Single-player worlds have local area network support, allowing players to join a world on locally interconnected computers without a server setup. Minecraft multiplayer servers are guided by server operators, who have access to server commands such as setting the time of day and teleporting players. Operators can also set up restrictions concerning which usernames or IP addresses are allowed or disallowed to enter the server.

You need to allow port 25565, which is the default port that Minecraft uses to allow connections. for ssh, which always uses port 22 by default.