How to Make a Multiplayer Server on "Minecraft"by Dan Taylor ; Updated September 22, 2017
A multiplayer server on Minecraft is a good way to team up with your friends to explore mine shafts and build huge structures. Minecraft, a sandbox building game, began development in May 2009 and allows players to freely explore a world made up of different types of blocks and use them to construct just about anything. Creating a multiplayer server can help you get the assistance you need to build something truly massive.
Upgrade to a premium Minecraft account if you don't already have one.
Download and install the Minecraft Server Software.
Click on "Start," "Run" and open "cmd" to go to the command prompt. Type the command "ipconfig /all" and hit enter, and write down the IP number that shows up.
Open your browser and enter this IP number in the address bar, and hit enter. The router will ask for a username and password. If you do not know this, you will have to call your internet service provider.
Find the tab for gaming or "port forwarding." Enter the desired port or ports you want to open. Enter your IP address (some routers will only ask for the last three digits). Click "Save Settings" or whatever the equivalent is for your router. You should now have a port open for a Minecraft multiplayer server.
Open Minecraft and log in.
Open the Minecraft Server Software and then type "op username" into the box, replacing "username" with your username.
Go back to the Minecraft window and click on "Multiplayer," and then type ":25565". Your server should now be ready.