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Factorio Multiplayer Guide: Playing With Friends on a Dedicated Server

Playing Factorio With Friends​

Factorio is a masterpiece solo, but multiplayer transforms it into something else entirely. Dividing responsibilities across a team, coordinating massive production chains, and debugging logistics together is deeply satisfying. But Factorio multiplayer has unique technical considerations that differ from most games.

This guide covers every way to play together, from quick sessions to persistent dedicated Factorio servers that run around the clock.

Connection Methods​

Factorio offers three ways to play multiplayer. Each has different tradeoffs.

Host and Play​

The simplest option. One player hosts the game from within their client, and others connect directly. The host's machine runs both the game client and the server simultaneously.

Pros: No setup required. Works immediately. Cons: The game is only available when the host is online. The host's internet connection and hardware become the bottleneck for all players. If the host's game crashes, everyone disconnects.

Dedicated Server (Self-Hosted)​

A standalone server binary runs on a separate machine or VPS. No game client is needed on the server. Players connect via IP address.

Pros: Runs 24/7 independently of any player. Better performance since the server is not also rendering the game. Full configuration control. Cons: Requires setup, port forwarding, and maintenance. You need a machine to dedicate to the server.

Dedicated Server (Managed Hosting)​

A hosting provider runs the server for you on enterprise hardware.

Pros: No hardware to manage, no port forwarding, instant setup, automatic backups, and professional uptime. Cons: Monthly cost (though typically less than running your own VPS).

For groups that play regularly, a dedicated server is the clear best choice. The factory stays online, and anyone can join whenever they want.

How Factorio Multiplayer Works​

Understanding Factorio's multiplayer architecture helps explain why certain issues occur and how to avoid them.

Lockstep Simulation​

Factorio uses a deterministic lockstep model. Every client runs the exact same simulation tick-by-tick. The server distributes player inputs, and every machine calculates the same result independently. This is why Factorio multiplayer can handle enormous factories without streaming massive amounts of game state data.

The downside is that every client must stay perfectly synchronized. If one client's simulation diverges even slightly, a desynchronization (desync) occurs and the affected player must resync.

Latency Hiding​

To make the game feel responsive despite network latency, Factorio uses a latency hiding system. When you click to place a building, your client simulates the action immediately without waiting for server confirmation. If the server later disagrees, the client corrects itself. In practice, this makes the game feel responsive even with 100+ ms ping.

UDP Protocol​

Factorio uses UDP on port 34197 exclusively. It builds its own reliable delivery layer on top of UDP to handle packet loss and reordering. This means standard TCP-based tools and diagnostics may not give you useful information about Factorio network performance.

Setting Up Your Multiplayer Session​

Connecting to a Server​

  1. Open Factorio and click Multiplayer.
  2. Choose Connect to address for direct connections, or browse the Server Browser for public servers.
  3. Enter the server IP and port (default: 34197).
  4. If the server requires a password, enter it when prompted.

Mod Synchronization​

If the server uses mods, your client must have the exact same mods and versions. The easiest solution is to check Sync mods with server in the server browser. This downloads the correct mod packages directly from the server.

This is critical. Even a minor version difference in one mod will cause immediate desyncs. Do not manually manage mod versions unless you are certain every player has identical files.

Avoiding Common Problems​

Desynchronization​

Desyncs are not caused by bad internet connections. They are caused by simulation disagreements, almost always from mismatched mods. Solutions:

  • Always use "Sync mods with server."
  • If you modified any mod files locally, revert them.
  • Server admins can run --check-consistency or use the console command /c game.force_crc() to diagnose the issue.

Lag and Slow Updates​

If the game feels sluggish, check the UPS (updates per second) counter. Factorio targets 60 UPS. If UPS drops below 60, the factory is too complex for the server's CPU. This is a simulation bottleneck, not a network issue.

Solutions:

  • Optimize your factory. Reduce belt throughput in favor of bots for late-game logistics.
  • Remove unused or redundant production lines.
  • Upgrade server hardware or switch to a host with better single-core performance.

Connection Timeouts​

If a player cannot connect at all:

  • Verify the server is running and reachable on UDP port 34197.
  • Check that port forwarding is correctly configured (for self-hosted servers).
  • Ensure the player's firewall is not blocking outbound UDP traffic.

Multiplayer Strategies for Teams​

Divide and Specialize​

In a group of 3-4 players, assign areas of responsibility:

  • Power and logistics: One player manages the power grid, train network, and main bus or logistics network.
  • Production chains: One or two players focus on specific production chains (green circuits, oil processing, science packs).
  • Expansion and defense: One player handles base perimeter expansion, military production, and biter defense.

This division prevents players from stepping on each other's toes and makes the factory grow faster.

Use Map Tags and Signs​

Factorio's map tags let you mark locations with notes. Use them liberally to communicate plans, mark resource patches for expansion, or flag areas that need work. This is especially valuable when players are not always online at the same time.

Coordinate Science Production​

Science pack production is the heart of progression. In multiplayer, agree on a target SPM (science per minute) and divide the production chains accordingly. A common approach is to have each player own one or two science pack production lines, all feeding into a shared set of labs.

Space Age Team Play​

With the Space Age expansion, multiplayer becomes even more engaging. Different players can manage different planets, each specializing in Vulcanus metalwork, Fulgora scrap recycling, Gleba biological processing, or Aquilo cryogenics. Space platforms connect everything together, creating a genuine interplanetary team effort.