The free-form Indie hit Minecraft presents players with a vast, procedurally generated world of blocks to destroy and build at will. The game's multiplayer mode allows you to cooperate to build grand structures or compete to raze your friends' castles to the ground. Since Minecraft lacks connection features such as a server browser or friend finder common to some other PC games, you'll need to give your server's IP address to anyone trying to connect. Use your operating system's configuration settings to find your IP, or use a third-party website.
Open the "Start" menu and select "All Programs." Open the "Accessories" file and click on "Command Prompt."
Type "ipconfig" into the Command Prompt window and press "Enter." This generates network information for all connected networks. The information may fill multiple screens if you have several connections.
Scroll down to the connection you want others to use with the Minecraft server and note the IP under the "Ipv4 Address" section.
Click the "Apple" menu and select "System Preferences" from the list. Click the "Network" icon in the Internet & Network section.
Click the "Show" drop-down menu. Click on the connection you want others to use to connect to your Minecraft server.
Click the "TCP/IP" tab. The connection's IP address appears along with other basic network information.
Open a Web browser.
Navigate to an IP-reporting website. Several sites provide this service (see Resources).
Note the displayed IP address and give it to anyone you want to join your Minecraft server. This address represents your external IP, and will not work for players joining from the same local network.
If you want to play Minecraft multiplayer on the same machine running the server, you don't need to enter your IP address. Just type "localhost" into the game's multiplayer connection box to start playing.
If the system is connected to a router, it will list the IP address as a variant of "192.168.1.X." This address is only valid for players connecting from the same local network. Use an IP-reporting website to find your external IP for nonlocal players.