Multiplayer



Multiplayer is the server-based version of the game that, as the name would suggest, enables multiple players to interact with each other on a single world. Players can work with others to create structures, mine and fight with each other.

Users can download and run the server package that allows other players to connect to and play on their server. Different game modes can be chosen for a server, which includes Survival, Creative, Hardcore, and Adventure. It should be noted that game modes are individually attributed to each player meaning some can be in creative and some in survival mode. Players can also be promoted to op (system operator) status by the server admin or other ops, which grants them access to server commands such as setting the time of day and teleporting players around.

Currently, Minecraft does not have an official pre-populated survival server list available, but there is a server list for Minecraft Classic, and the wiki's sidebar has a link to it and there are also third-party server lists available (such as the Minecraft Forums maintained server list).

An option available for players who do not wish to port forward is set up their server on a local network (using the local IP address as opposed to a global IP address presented by the server's router). A local server does not require port forwarding.

Variations of servers
Servers can be classified into a server type, there are a multitude of server types available:
 * SMP (Survival Multiplayer) The standard server type and when creating a server, will by default, become SMP.
 * CMP (Creative Multiplayer) Players have unlimited health and resources. Useful for team building purposes.
 * HMP (Hardcore Multiplayer) Players are permanently banned from the server once they die.
 * AMP (Adventure Multiplayer) Players can build but not destroy blocks. Useful for preventing certain types of griefing.
 * There are also servers dedicated to provide their own purpose that do not fit under standard server types.

Some servers use mods ("modifications") to add custom items, crafting recipes, and more that are dedicated to enhancing the vanilla Minecraft multiplayer experience.

Chat


Please note: Several of these commands are configurable (the defaults are shown here)

In multiplayer, players can press to chat to others or enter commands. Commands are identified by the server with the use of a forward slash (/) at the beginning of the message. Chat functions include:
 * Chat history - Mouse wheel can be used to scroll up/down for history. and  keys can also be used.
 * Clickable links in chat.
 * Up/down keys for recently sent messages.
 * If you start typing a player's name or a command, and press, it'll automatically type the rest of the username or command for you. (Will not finish player name if player isn't online.)
 * Copy & paste in chat. ( is for paste and is to copy.  will select text for you.)
 * The section symbol, §, allows players to change the style of the text.
 * Just like typing §k in chat displays random characters, §l §m §n and §o creates bold, striked, underlined and italic text respectively, while §r resets any set states. These (the section symbol: §) cannot be typed in vanilla clients because they are restricted from being typed. If § is pasted and posted in chat, the player who sent it will be automatically kicked from the server with an "Illegal characters in chat" message, and a disconnect.endOfStream error server-side.
 * Pressing the '/' acts like a command key: it opens the chat with a '/' in it. In other keyboard layouts, it might be another key. Since version 1.3.1 it is possible to change the key in the Controls options.
 * Pressing a letter or typing the first few letters of a username and then pressing enters the first username starting with that letter or phrase. If there are multiple with that letter (or phrase), it will give a list in chat and pressing tab more than once scrolls through the names.
 * You can also do this with commands: Type / and the first letter of the command.
 * Just typing / and then tab will list all commands
 * Some commands will also have additional parameters added with just pressing tab at that point.

Third-party server lists
In Beta 1.8, a Server list was introduced to the multiplayer menu. This does not have a full server list, however, but it does save servers that you add, shows you your current latency to them, and can tell you the number of players online and the maximum allowable connections.

The Minecraft site contains a server list for Classic servers. There is currently no official server list for current game versions, but there are several sites that allow players and/or server owners to add their server to a list, providing site visitors with current server stats such as players connected, uptime, and more.

Local area network
A LAN game is only accessible to other people in your local network (e.g. just the people also connected to your router/switch are able to connect to you) unless you setup port forwarding on your router, then people can direct connect with your IP and Port. (ex. 12.123.456.101:43787)

To open your current single player world for other players in your LAN, type the command into the chat (note that this is still very restricted, e.g. you can't adjust the game options using the commandline) or access the Game Menu and click on the "Open to LAN" button. There you can select the gamemode for other players and whether they should be allowed to use Cheats. Both of these methods give you an IP for use, for example: "Local game hosted on hostname:12345". If you type and want to change the default gamemode, type  for example. Note: two computers using the same Minecraft account name cannot connect with this method.

Now other players can either connect to your game using the link minecraft provided you or they can connect using the multiplayer menu with its new "Scanning for LAN-Worlds" section at the bottom.

On the technical side a minecraft client with an opened LAN game sends a UDP multicast to the local address 224.0.2.60:4445 every 1.5 seconds. Other clients then listen for this multicast to show your game in their multiplayer menu.

Technical notes
In Classic, the server saves the level to the server_level.dat file every minute, or by issuing the command. In the full game, the server saves the level in the "world" folder every 30 seconds if chunks have been modified, by default.

Home-made servers do not strictly require access to minecraft.net, and so can be played on an isolated local network with no Internet connection. They use minecraft.net as a repository of player skins and also a database containing a list of accounts, preventing hackers and griefers from using false names while on such a server. This and other settings are modified by editing the server.properties text file.

Bugs
Internal exception: java.net.SocketException: Connection reset by peer: socket write error
 * Many events of the game are affected by bad multiplayer lag, with effects such as resulting in mobs hitting you more easily than in singleplayer.
 * Sometimes your skin changes back to default skin. This often happens when leaving/entering the Nether or the End, or when teleporting.
 * In multiplayer, players sometimes glitch through a block or may seem as if they were hovering over a block.
 * Blocks will sometimes appear to be destroyed on the client's side, yet still exist on the server. This will cause the player who sees the invisible block to vibrate when attempting to enter the space that the block occupies. (One solution is to put back the blocks, this will not decrease the number of blocks in your inventory, and then mine the blocks again.)
 * There is a rare bug that can occur on any server depending on the internet connection used to access the server. This bug is currently known to occur mostly on college/university hosted internet sources in which multiplayer would crash consistently; rendering the player unable to use multiplayer without having to connect from a new location with a different IP address. The only things that will load prior to being auto-kicked by the connection is the chunk that the user was last standing on prior to logging off from a previous session using a different IP address or connection. The bug would also display the following error message before returning the player to the title menu:
 * Another bug that occurs on slower servers will prevent the sleeping action even if all players are in a bed.
 * Hardcore in select LAN world gamemode selection will not be available.

Trivia

 * In multiplayer, one is able to change the gamemode by simply using a command (this requires operator status). (For example, converts the player's gamemode to Creative (Survival is 0, Creative is 1, and Adventure is 2.)
 * When changing the game mode, all current items in the inventory will be preserved.