Server Setup - Factorio Wiki

Factorio Guide • Updated Jan 6, 2026

Server Setup

Setting up a Factorio dedicated server allows you to create a persistent multiplayer world where you and your friends can build factories together. This comprehensive guide covers everything from initial setup to advanced configuration and troubleshooting.

Prerequisites

Before starting, ensure you have:

Factorio server files installed (headless version recommended for dedicated servers)
At least 2-8 GB of RAM available (scales with player count and factory size)
Port 34197 (UDP) accessible through your firewall
A save file or ability to generate a new world

Server Requirements

RAM and CPU requirements scale with the number of players and factory complexity:

RAM Requirements

2 GB RAM - 1-4 players, small to medium factories
4 GB RAM - 5-12 players, medium to large factories
8 GB RAM - 12+ players or megabase builds
16+ GB RAM - Very large multiplayer megabases

CPU Considerations

Factorio is single-threaded for game updates. A high clock speed CPU (3.5+ GHz) performs better than multi-core processors with lower speeds. UPS (Updates Per Second) should remain at 60 for smooth gameplay.

Installing the Server

Downloading Server Files

Download the headless server from Factorio.com
Extract the archive to your desired directory
The headless version has no graphics and is optimized for dedicated servers

Creating Your First World

A dedicated server requires a save file. You can create one several ways:

Method 1: Generate via Command Line

./factorio --create my-save

This generates a new world with default settings.

Method 2: Custom Map Generation

./factorio --create my-save --map-gen-settings map-gen-settings.json --map-settings map-settings.json

Use JSON configuration files to customize terrain, ore placement, enemy settings, and more.

Method 3: Upload Existing Save

Copy a save file from your local game to the server's saves directory: ./saves/

Basic Server Configuration

Server Settings File

The server-settings.json file (located in ./data/) controls all server behavior:

{
  "name": "My Factorio Server",
  "description": "Welcome to my factory",
  "tags": ["game", "tags"],
  "max_players": 10,
  "visibility": {
    "public": true,
    "lan": true
  },
  "username": "your-factorio-username",
  "token": "your-auth-token",
  "game_password": "",
  "require_user_verification": true,
  "max_upload_in_kilobytes_per_second": 0,
  "max_upload_slots": 5,
  "minimum_latency_in_ticks": 0,
  "ignore_player_limit_for_returning_players": false,
  "allow_commands": "admins-only",
  "autosave_interval": 10,
  "autosave_slots": 5,
  "afk_autokick_interval": 0,
  "auto_pause": true
}

Important Settings Explained

name - Server name shown in public browser
max_players - Maximum concurrent players (0 = unlimited)
visibility.public - List on public server browser
username/token - Required for public servers (get token from factorio.com)
game_password - Password protect your server
require_user_verification - Players must have Factorio accounts
auto_pause - Pause when all players disconnect (saves UPS)
autosave_interval - Minutes between autosaves
allow_commands - Control who can use console commands

Starting Your Server

Basic Start Command

./factorio --start-server my-save --server-settings server-settings.json

Advanced Start Options

./factorio --start-server my-save \
  --server-settings data/server-settings.json \
  --port 34197 \
  --bind 0.0.0.0:34197 \
  --rcon-port 27015 \
  --rcon-password admin123

Running as Background Process (Linux)

Use screen or systemd to run the server in the background:

screen -S factorio
./factorio --start-server my-save --server-settings data/server-settings.json
# Press Ctrl+A then D to detach
# Reattach with: screen -r factorio

Port Forwarding and Firewall

Required Ports

34197 UDP - Game port (configurable with --port)
27015 TCP - RCON port (optional, for remote administration)

Linux Firewall (UFW)

sudo ufw allow 34197/udp
sudo ufw allow 27015/tcp  # If using RCON
sudo ufw reload

Router Configuration

Access your router admin panel (usually 192.168.1.1 or 192.168.0.1)
Find Port Forwarding settings
Forward UDP port 34197 to your server's local IP
Save and restart router if required

Managing Mods

Installing Server Mods

Place mod zip files in ./mods/ directory
Create or edit ./mods/mod-list.json to enable/disable mods
Restart server to load new mods
Clients will auto-download enabled mods when connecting

Mod Sync

Factorio handles mod synchronization automatically:

Server sends mod list to connecting clients
Missing mods download from mod portal
Clients must restart after downloading
All players must have identical mod versions

Admin Management

Admin List

Create ./server-adminlist.json to grant admin privileges:

[
  "PlayerUsername1",
  "PlayerUsername2"
]

Whitelist (Optional)

Create ./server-whitelist.json to restrict access:

[
  "AllowedPlayer1",
  "AllowedPlayer2"
]

Common Issues and Troubleshooting

Network Communication Error

Error: "Couldn't establish network communication with server"

Solutions:

Verify server is actually running
Check UDP port 34197 is open in firewall
Confirm router port forwarding is configured
Test with direct IP connection instead of server browser
Ensure server isn't binding to localhost only (use 0.0.0.0)

Desynchronization Issues

Symptoms: Players getting kicked with "desync" messages

Causes and Solutions:

Mod mismatch - Ensure all players have identical mod versions
Determinism issues - Some mods cause desyncs; disable suspect mods
Network instability - Check player ping and packet loss
Save corruption - Restore from earlier backup

Low UPS (Updates Per Second)

Symptoms: Game running in slow motion, UPS below 60