Multiplayer

In addition to being a single-player game, Factorio also supports multiplayer, allowing many players to cooperate and assist each other, or work against each other in pvp. This page documents how to set up a multiplayer game, and how to join one. By default, multiplayer games run the CO-OP freeplay scenario where all players work together to launch a rocket with a satellite into space. Other scenarios, including PvP maps, are available for download from the Maps and Scenarios forum.

Setting Up a Multiplayer Game

Multiplayer games can be joined, hosted while playing, or hosted by a dedicated server. Multiplayer games can be advertised to other players on the same LAN or worldwide.

Use the Multiplayer button in the Play menu to start playing a multiplayer game, choose New or Load or Scenarios to host and play, or Browse or Play on LAN to connect to an already-running game. The host can also choose not to advertise the game at all, in which case you'll need the server's (public or otherwise reachable) IP address; you can then Connect directly to that to join the game.

Notes and tips:

Dedicated/Headless server

As of Factorio version 0.12.0 onwards, a dedicated (or headless) server can be started using the --start-server command line option. You can run factorio --help to get a list of all command-line arguments that Factorio accepts.

In the headless mode:

Please note that there has been a slight change between 0.12, 0.13 and 0.14 in how --start-server (and others) interpret the given parameter. Version 0.12 expected --start-server to be followed by a save name, that was to be found in the saves directory. 0.13 instead expects --start-server to be followed by a path to a save file. I.e. if you did factorio --start-server foo in 0.12, you probably want to use factorio --start-server saves/foo.zip in 0.13.

You will need to create your save file before you start the server, as the dedicated server REQUIRES a save file to be provided. This can easily be done using the --create command-line argument. For example: 

./bin/x64/factorio --create ./saves/my-save.zip       # This creates a new save, as if by clicking the New Game button in the GUI

./bin/x64/factorio --start-server ./saves/my-save.zip # This starts a server that will host the file created on the previous line

There are several JSON configuration files that factorio can make use of to change the server and map settings:

Example files for each of these parameters are included in the data subdirectory.

The --map-gen-settings and --map-settings options must be used with the --create option when you create a new map. For example: 

./bin/x64/factorio --create saves/my-save.zip --map-gen-settings my-map-gen-settings.json --map-settings my-map-settings.json

Starting the factorio server requires you to specify the location of the server-settings.json file. By default this is in the factorio data folder. For example to start factorio using the most recent saved map, you would run: 

./bin/x64/factorio --start-server-load-latest --server-settings ./data/server-settings.json

Setting up a Linux Factorio server

This step-by-step guide has been verified on fresh CentOS 7 and RHEL 7 installs but should be applicable with little to no changes on most distributions.

The guide assumes you will install the headless server under /opt/factorio, adjust paths according to your own setup. We will also suggest that you run the Factorio server as a separate user to harden security of your setup.

Note that there are two distinct packages for Linux that can be used to run a headless server. First is the usual Linux download, that contains the full game. The other is the special headless package. The headless package does not contain any files irrelevant for a pure server, such as graphics and sounds. It is also not linked against libraries that may not be present on a server machine, such as Xlib, libGL or libasound. This option should be selected if running in a 3rd party hosted server.

This guide does not handle firewall/port forwarding since this can be done in various ways on Linux (make sure to read up how this is done as a Linux admin on your particular distribution)

You can use the Linux factorio-init script to start/stop your headless server in a much better way. The script will ensure you only ever use the most recent save when your server starts (even if that was an auto-save) while also letting you set a number of other settings like Autosave frequency and Latency settings. This script will also simplify updating the server when combined with the Linux factorio-updater script. 

$cd /opt/

$sudo tar -xzf /tmp/factorio.tar.gz # Use the correct file name. It includes the factorio version number.
$useradd factorio
$chown -R factorio:factorio /opt/factorio
$su factorio
$/opt/factorio/bin/x64/factorio --start-server savename

As long as it fails saying it cannot find/open the savename.zip you are set! Just upload a save from your own computer and put it in the /opt/factorio/saves directory, or use the --create ./saves/newgame.zip argument.

How to list a server-hosted game on the matching server

In order to publish the game to the matching server, Factorio needs to be given some more information than just the save file location. These information are provided in a server settings file.

To create a server settings file, look at the example file located in data/server-settings.example.json in the Factorio Application Directory. The recommended way is to make a copy of this example file and edit the copy.

The following values can be changed:

Name
This will be the name under which the server will be listed in the server browser
Description
A brief description of your server
Tags
A list of game tags
Max Players
Allows you to limit the number of players that can be connected to the server at the same time. If you want no limit, just set max_players to 0.

(There are additional values in v0.14 of factorio.)

Technical Implementation Details

Notes about some technical details surrounding multiplayer have been published by the development team in several Friday Facts blog posts:

More Guides

Miscellaneous Tips

/c game.players["player_name"].color = {r=0.7, g=0.5, b=0.1, a=0.9}

r, g and b are for red, green and blue respectively (possible values are between 0 and 1, use the right-most column on http://prideout.net/archive/colors.php to convert colors to rgb numbers). a is alpha channel aka transparency of the color to the base texture.

Joining a Multiplayer game

As of version 0.13, players no longer necessarily have to port-forward to play with others. Players may join each other through Steam, or by just the port-forwarded host.

Players wishing to join a game may do so in multiple ways:

It is recommended that players use voice chat (TeamSpeak, Discord, Mumble) because you need to talk a lot to coordinate connections, building, handling attacks, etc. TeamSpeak servers are posted in the multiplayer forum. The public Discord of the Factorio community can be found here.

Joining by IP

To join a multiplayer game by IP, you will need to know the public IP of a valid server. You can find this through social media, websites, or by word of mouth. After acquiring the IP and port, simply go to play -> Multiplayer -> Connect to server, and provide all the information it asks for.

If the server has been set up correctly to accept public connections, you should be able to join the game.

Joining via server list

Factorio's devs keep a list of all public servers that declare themselves to the service, allowing players to join directly through Factorio. Most of these servers will be password-requiring, but many completely public servers can be connected to. To join via server list, go to Play -> Multiplayer -> Browse public games. Provide your Factorio.com login if asked, and a list of public servers will appear. Simply select one.

Joining through Steam

Steam provides a "game invite" system, simply use that to join. You can find more info about how to use steam in it's documentation. This is the most recommended way for the average player to use multiplayer with their friends, as it allows Steam to handle everything.

Joining a local LAN game

If you have some friends on the same internet connection as you (in the same building or network), you may play a LAN game. Simply go to Play -> Multiplayer -> Play on LAN.

Finding Other Players


Connecting to a Server Behind NAT

Factorio requires that the server (in client-server mode) have a publicly accessible IP address or that all players are on the same LAN. If you are behind NAT, you must set up port forwarding (see above for port number) or use virtual LAN software such as Hamachi or Evolve.

Multiplayer games will be launched in client-server mode (also multiplayer forwarding mode). In this mode, all clients send their network traffic to the server and the server forwards the traffic to the other clients. The advantage of this is that it allows games where some players are inside a LAN and others are outside. The disadvantage may be slightly more lag as packets must travel an extra hop (through the server).

PvP

In PvP mode, players can be on different forces. Each force can have one (free-for-all) or more players (teams). Each force has its own independent research progression. Additionally, each force's turrets and combat bots will attack other players as enemies, unless a cease fire is set. Note that, depending on the scenario, cease fires may be unidirectional — setting a cease fire with an opposing force does not guarantee a cease fire from them in return.

To start a PvP game, you can select the 'PvP' scenario from the 'Play' menu, or download a custom scenario which also supports PvP.

After downloading a PvP scenario, you need to move it to your application directory, and create the multiplayer game using the scenario.

  1. Download the scenario and place the scenario directory in the scenarios directory within your user data directory.
  2. Launch Factorio
  3. Click Play
  4. Click Multiplayer
  5. Click Scenario
  6. Choose the PvP scenario you want and click Create
  7. Choose latency and other settings, then click Play
  8. Other players can now join the game

Forces

Forces can be manually created via the console. This allows any map/scenario to be used for PvP. This may not be as convenient as a pre-made PvP scenario, as there will be no way for players to turn on/off cease fires other than through the console.

Each created force has its own research progression and different forces may attack each other.

The console commands for setting up and controlling forces are below: 

game.create_force("Name")
--Creates the force "Name"

game.players["Player_name"].force = game.forces["Name"]
--Sets this player to the new force

game.forces["Name"].set_cease_fire("Other_force_name", true)
--Sets the new force ceasefire to the "other force"

game.forces["Name"].set_spawn_position({x = 10, y = 20}, game.surfaces[1])
--Sets the spawn position of the force

game.print(#game.forces)
--Prints the number of forces

for name, force in pairs (game.forces) do
   game.print(name)
end
--Prints the name of all the forces


History

Narrative history

Because of the potentially immense amount of activity on a map, the game engine utilizes a lock step architecture. All instances of the game run full simulations of the entire world and only player actions are transferred across the network.

Multiplayer games were introduced to Factorio with version 0.11.0. The only connection method available was peer-to-peer mode which meant every player had to be able to directly communicate with every other player. In version 0.12.4, a client-server mode of communication was introduced in which the server (either a dedicated one or the player who hosted the game) relays messages to all peers. This means that direct connection between all players is no longer necessary. As of version 0.13, P2P connecting is completely removed.

As of version 0.12.0, the game features "latency hiding" mechanics where the game simulates some of the player's actions locally to make some common interactions (such as moving the player's character) more fluid. Latency hiding is enabled by default, but it can be enabled or disabled in Options → Other → Enable multiplayer latency hiding. Not every action is a part of latency hiding – most notably, car or train driving and shooting are not a part of it. It is recommended to keep this on, as many actions will be very stuttery on a low end internet connection.