How to Make a Factorio Server Public (Client and Headless Server Guide)

To make a Factorio server public, set its visibility to Public, publish it through Factorio’s matching service with Factorio.com credentials or an authentication token, and make its UDP port reachable from the internet. The default port is 34197/UDP. For an occasional session, use the game client’s multiplayer host screen; for a world that should stay online without your game client, run the dedicated headless server with a save file and server-settings file.

Playing with friends? Godlike.Host runs hosted Factorio servers from 10 data-center locations, with free DDoS protection.

Friends can then find the game under Browse public games, use Steam’s join flow when Steam visibility is enabled, or connect directly with your public IP address and configured port. Every player must use the same Factorio version and matching mods.

#	Preview	Product	Price
1		CyberPowerPC Gamer Xtreme VR Gaming PC, Intel Core i5-13400F 2.5GHz, GeForce RTX 5060 8GB, 16GB...	$1,282.00	Buy on Amazon
2		ZER-LON Prebuilt Gaming PC Desktop, Core I7 up to 3.9 GHz, RX 550 4GB GDDR5	$469.99	Buy on Amazon
3		Mumba Mouse Grip for Nintendo Switch 2 Joy-Con, [2 Pack] Ergonomic Gamer Grip Holder with Super...	$24.29	Buy on Amazon

As an Amazon Associate I earn from qualifying purchases.

Choose the right way to host

Factorio has two practical public-hosting approaches. Client hosting is quickest: your running game acts as the server, so the world is available only while that session remains active. A dedicated headless server is better for a persistent map, scheduled restarts, or a community server because it runs separately from the game client.

Use client hosting for a short cooperative session. Use headless hosting when the map should remain available while the original host is offline or when you want the server process separated from the game client.

#1 Best Overall

Sale

CyberPowerPC Gamer Xtreme VR Gaming PC, Intel Core i5-13400F 2.5GHz, GeForce RTX 5060 8GB, 16GB DDR5, 1TB PCIe 4.0 SSD, WiFi Ready & Windows 11 Home (GXiVR8060A40)

• System: Intel Core i5-13400F 2.5GHz 10 Cores | Intel B760 Chipset | 16GB DDR5 | 1TB PCIe 4.0 NVMe SSD | Windows 11 Home
• Graphics: NVIDIA GeForce RTX 5060 8GB Graphics | 1x HDMI | 2x DisplayPort
• Connectivity: 1 x USB-C 3.2 | 2 x USB-A 3.2 | 6 x USB-A 2.0 | 1 x LAN | WiFi 6 | Bluetooth 5.3 | 7.1 Channel Audio
• Tempered Side Case Panel | Custom RGB Lighting | Keyboard and Mouse
• 1 Year Parts & Labor Warranty, Free Lifetime Tech Support

$1,282.00

Buy on Amazon

Understand Factorio’s visibility settings

Factorio exposes three visibility choices. They control where the game is advertised, not whether your router or firewall will pass traffic.

Public

Public publishes the game to Factorio’s official matching service and places it on the public games list. This is the setting required when strangers or friends should be able to discover the server by browsing public games.

Steam

Steam controls Factorio’s Steam-based joining feature. It can make joining through Steam convenient, but it is not the same as appearing on the public games list. A server can use Steam joining without being advertised publicly.

LAN

LAN advertises the game only on the local network. It is useful for computers connected to the same home or office network, but it does not make the server publicly reachable over the internet.

You can choose more than one applicable visibility path where the interface or settings allow it. If your goal is a listing that anyone can browse, make sure the Public option is enabled rather than relying only on Steam or LAN.

Make a public server from the Factorio client

This method is the fastest way to expose an existing world for a play session.

1. Start Factorio and open the Multiplayer menu.
2. Choose Host new game for a new map or Host saved game for an existing save.
3. Select the map, scenario, save, and mod set you want to run.
4. When the hosting options appear, set the server visibility to Public. Enable Steam joining as well if you want players to use Steam’s join flow, and use LAN only for local-network discovery.
5. Start the game and keep the hosting session running. Closing the host session stops this server instance.
6. Give players the public listing name, or provide your public IP address and the configured port for a direct connection.

Client hosting still depends on the network path being reachable. If the game appears in your own client but nobody outside your network can join, continue with the UDP forwarding and firewall steps below.

Run a persistent public headless server

The dedicated server is the appropriate choice for an always-on world. Factorio’s official guidance requires a save file and a server settings file. Linux users can obtain a free, lightweight dedicated headless-server package from Factorio.

Prepare the required files

• Save file: the world you want the server to load.
• server-settings.json: the server’s visibility, credentials, and other server options.
• Server executable: the dedicated/headless Factorio package for the operating system you are using.

Keep the settings file protected. It is plain text, and public dedicated listings require Factorio.com credentials or an authentication token. Anyone who can read the file may be able to obtain those credentials.

Set Public visibility and credentials

Open server-settings.json in a text editor. In the visibility section, enable the public setting. Supply the Factorio.com account fields or an authentication token required for public listing. Do not post the token in chat, screenshots, issue reports, or a publicly readable repository.

{"visibility":{"public":true,"lan":false},"username":"","token":""}

The exact settings file contains additional options; preserve valid JSON syntax and retain the rest of the file’s settings. If you use a token, the security recommendation is to prefer it over storing a reusable password in a plain-text document.

Start the server

Run the Factorio executable with the save and settings files. A generic command is:

factorio --start-server my-save.zip --server-settings server-settings.json --port 34197

Replace the save filename and paths with the files on your machine. The --start-server option loads the world, --server-settings applies the server configuration, and --port chooses the listening port. If you omit --port, Factorio uses its default port, 34197.

Keep the process running and watch its console output for startup or authentication errors. The server must be fully started before players attempt to join. For unattended operation, run it under the operating system’s normal service or process-supervision mechanism, but make sure that mechanism does not expose the settings file or token to other users.

Rank #2

ZER-LON Prebuilt Gaming PC Desktop, Core I7 up to 3.9 GHz, RX 550 4GB GDDR5

• 【PC Gaming System】This gaming PC is loaded with Intel Core I7 up to 3.9GHz and AMD Radeon RX 550 4G graphics card, allowing you to experience top-notch gaming performance. This system features 16GB of high-speed memory and 512GB SSD Solid State Drive for lightning-fast load times
• 【Superior Gaminig Experience】This high-performance Gaming Computer Desktop is capable of running a wide range of popular PC games for pc gamer, including Fortnite, Call of Duty Warzone, Escape from Tarkov, GTA V, World of Warcraft, LOL, Valorant, Apex Legends, Roblox, Overwatch, CSGO, Battlefield V, Minecraft, Elden Ring, Rocket League, The Division 2, and Hogwarts Legacy with 60+ FPS
• 【Multifunctional Use】This tower computers gaming pc desktop is designed to meet the needs of different people on the computer, powerful performance not only in the game to show quality graphics, the face of the office, design, audio and video can also be comfortable, multi-tasking, fast switching smooth operation
• 【Tower Gaming PC Desktop】The gaming computer desktop is designed for versatile connectivity, featuring 2x USB 3.0 ports, 6x USB 2.0 ports, 1x RJ-45, 1x Serial, and built-in Wi-Fi. The AMD Radeon RX 550 4G GDDR5 Graphics Card supports multiple display options including 1x HDMI, 1x DisplayPort, and 1x DVI, ensuring compatibility with a wide range of monitors

$469.99

Buy on Amazon

Open the network path: UDP port forwarding

Factorio servers use UDP, not TCP, for the game connection. The default is UDP port 34197. If the server is behind a home router, create a port-forwarding rule that sends UDP 34197 from the router to the host computer’s current private IP address.

1. Find the host computer’s private address on the local network.
2. Reserve that address in the router’s DHCP settings or assign a stable local address so the rule does not point to a future, different device.
3. Create a forwarding rule for UDP, using external port 34197 and internal port 34197 unless you intentionally use different port numbers.
4. Set the destination to the host computer’s private IP address.
5. Save or apply the router configuration.

Do not create only a TCP rule. A TCP-only forward will not provide the required Factorio game path. Also check that the router does not randomize the source port, because that can interfere with the expected connection behavior.

When you change the port

The listening port is configurable. If you start the server with another value, forward that actual UDP port instead of 34197 and give direct-connection players the same value. For example, a server started with --port 34200 requires UDP 34200 to be forwarded and allowed through the firewall.

Allow the port through the host firewall

The operating system’s firewall must allow inbound UDP traffic on the configured port to the Factorio server process. Add an inbound rule for the same UDP port used in the router, then restart or reload the server if your firewall requires it. A correct router rule cannot help if the host firewall silently drops the packet.

Test that the server is genuinely public

Test from outside the host’s local network. A local test can succeed even when the router blocks internet traffic or when the public address cannot be reached from inside the same network.

1. Start the client-hosted or headless server and wait until it has finished loading.
2. From another connection, open Multiplayer → Browse public games and search for the server name.
3. If you use Steam visibility, test Steam’s join flow separately.
4. For a direct test, choose Multiplayer → Connect to address and enter the server’s public IP address plus the configured port.
5. Confirm that the joining client uses exactly the same Factorio version and the same mods as the server.

Use a friend on a different internet connection or a device using mobile data for the outside test. Testing from the same Wi-Fi network may be affected by the router’s hairpin-NAT behavior and does not prove that an internet player can connect.

How friends join

Public-list method

Ask friends to open Multiplayer → Browse public games, search for the server name, and select it. This is the simplest method when the server is listed publicly and the name is distinctive.

Steam method

If Steam visibility is enabled, friends can use Factorio’s Steam join feature. This is a separate discovery path from the public list, so a server that is not publicly listed may still be joinable through Steam when the underlying hosting and network conditions support it.

Direct-IP method

Give friends the public IP address and configured port. They should open Multiplayer → Connect to address, enter the address in the appropriate format, and connect. If you changed the port, include that changed value; do not assume 34197.

Never give players your private LAN address when they are outside your home network. Addresses such as 192.168.x.x, 10.x.x.x, or 172.16.x.x through 172.31.x.x are local addresses and are not the public endpoint your friends need.

Why a public server does not appear in the list

The visibility setting is not public

Open the client’s hosting options or server-settings.json and verify that Public visibility is enabled. A LAN-only setting or Steam-only setting will not produce the same public-list result.

Credentials or token are missing

Dedicated public listings require Factorio.com credentials or an authentication token. Check that the account fields are populated, that the token has not been revoked, and that the server process is reading the settings file you edited. A common mistake is changing one copy of server-settings.json while the command points to another copy.

The settings file is invalid

Malformed JSON can prevent settings from loading. Check commas, braces, quotation marks, and the visibility object. If the server reports a settings parse error, restore a known-valid file and reapply only the required changes.

The server has not completed startup

A process can exist while the world is still loading or while authentication is failing. Wait for a normal ready state in the console and resolve any login or file errors before troubleshooting listing behavior.

Rank #3

Sale

Mumba Mouse Grip for Nintendo Switch 2 Joy-Con, [2 Pack] Ergonomic Gamer Grip Holder with Super Smooth PTFE Glide Pads Portable Gaming Controller Stand for Switch 2 Joy Con Accessories (2025), Black

• Compatibility: Designed specifically for the Nintendo Switch 2 Joy-Con controllers, with dedicated left and right grips. It provides a more comfortable and precise control experience for smoother gameplay.
• Ergonomic Design: This comfortable Switch 2 controller grip is designed to fit the shape of your hand, with finger grooves for a stable and secure grip, helping you stay relaxed during long gaming sessions.
• Zero Resistance: The precision-crafted ABS shell and unique Teflon feet provide an ultra-smooth movement experience, making your control more precise. Whether it's shooting, strategy, or simulation games, you can enjoy an intuitive and seamless connection with the game.
• Quick & Easy Setup: Align the "+" and "-" buttons on your Switch 2 Joy-Con with the corresponding markings on the mouse grip, then snap it into place for immediate use, so you’re ready to game in seconds with enhanced precision.
• Lightweight and Portable: Weighing only 34.2g, it’s easy to carry and lets you enjoy a professional-grade gaming experience anytime, anywhere.

$24.29

Buy on Amazon

Why the server is listed but unreachable

Wrong forwarding target

Compare the router rule’s destination with the host computer’s current private IP address. If DHCP assigned a new address, the rule may now point to another device or nowhere at all.

TCP was forwarded instead of UDP

Replace a TCP-only rule with a UDP rule for the configured Factorio port. If the router offers separate protocol choices, select UDP; if it offers a combined option, verify that UDP is included.

The host firewall blocks the port

Allow inbound UDP on the exact port used by the server. Check both the firewall rule and the profile it applies to, such as a private or public network profile.

The router or ISP uses restrictive NAT

Factorio can use Steam or NAT traversal in some hosting situations, but a server that remains behind NAT without a working traversal path needs port forwarding or a virtual-LAN method. If your internet provider places your router behind another layer of carrier or upstream NAT, a forwarding rule on your own router may not be sufficient. In that case, ask the provider whether inbound port forwarding is available or use a virtual-LAN approach that puts all players on a shared private network.

The public address is changing

A changing public IP address invalidates an old direct-connect instruction. Give players the current public address whenever it changes, or use the public-list method so they do not need to know the address.

Version and mod compatibility

Factorio clients must match the server’s game version and mod set. A player can see the listing and still fail to join if the client is on a different version or lacks a required mod. Before investigating advanced networking, have the player compare:

• The exact Factorio version shown by the client and server.
• The enabled mods and their versions.
• The save’s required mods, especially after a server restore or migration.
• Any server-side setting that requires user verification or a game password.

When you change the server’s mods, restart it and tell players to synchronize their own installations before trying again. Keep a backup of the save before making large mod changes so that you can roll back if a mod dependency prevents the world from loading.

Run more than one public server

Each Factorio server instance needs its own configured port. Start every instance with a distinct --port value, forward each UDP port to the correct host and process, and ensure the operating-system firewall allows all of them. Do not point two running instances at the same port or the second process will not have a unique listening endpoint.

Use separate save files and settings files for separate worlds. Keep each instance’s credentials and visibility settings in the file referenced by that instance’s startup command so that changing one server does not accidentally alter another.

Security practices for a public server

• Use an authentication token rather than placing a reusable account password in a plain-text settings file when possible.
• Restrict access to the settings file and server directory to the account that runs Factorio.
• Share only the public IP address and game port with players; never share the token or the settings file.
• Keep the server software and mods updated in a controlled way, taking a save backup before changes.
• Use a separate game password or access controls if your chosen server settings support them, especially when the public listing is intended for a known group.
• Monitor the server console for repeated authentication, loading, or connection errors.

A public listing is an invitation for unknown players to attempt to connect. Decide in advance who can build, whether the map should be password-protected, and how you will remove disruptive players. Public visibility and unrestricted gameplay are different choices.

Practical player capacity

Factorio’s documented hard limit is 65,535 players, but that is a technical ceiling rather than a realistic target for a normal self-hosted machine or internet connection. The practical capacity is much lower and depends on the host hardware, simulation load, mods, network quality, and what players are doing in the world. The hard-limit figure should not be used as a promise of supported or playable capacity.

Self-hosting versus managed hosting

Self-hosting gives you direct control over saves, mods, settings, ports, credentials, and the network path. It also makes you responsible for Linux or operating-system administration, backups, firewall rules, router configuration, updates, and recovery when the host or internet connection fails.

Managed hosting removes much of that administration in exchange for a recurring fee and the provider’s control over the underlying machine. Evaluate a service on the points that matter for your map:

• Recurring cost: self-hosting uses your existing hardware and connection; managed hosting adds an ongoing service charge.
• File and mod control: confirm that you can upload saves, install the mods you need, and edit server settings.
• Maintenance: decide whether you want to handle updates, restarts, logs, and firewall work yourself.
• Backups: check how saves are backed up, how often, and how restoration works.
• Geographic latency: choose a server location close to most players when responsiveness matters.
• Port and settings flexibility: verify that you can change the Factorio port and relevant server options.

Do not choose managed hosting merely because the public list is difficult to configure. First determine whether the real obstacle is a missing UDP forward, an ISP-level NAT restriction, or a credentials error; those problems can persist regardless of where the server is hosted.

A complete public-server checklist

• Choose client hosting for a temporary session or a headless server for persistence.
• Enable Public visibility; enable Steam or LAN only for the additional joining paths you actually want.
• For a headless server, prepare a save file and valid server-settings.json.
• Provide Factorio.com credentials or an authentication token for public dedicated listing.
• Protect the plain-text settings file and keep the token private.
• Start the server with --start-server; use --server-settings and, when needed, --port.
• Forward the configured port as UDP from the router to the host’s current private IP address.
• Allow the same UDP port through the host firewall.
• Test from outside the local network using the public list or direct IP.
• Confirm that every client uses the same game version and mods.
• If multiple servers run on one network, assign each a distinct port and forwarding rule.

What success looks like

A correctly configured public server has Public visibility enabled, valid listing credentials, a running Factorio process, and a reachable UDP path from the internet to the host. Players can discover it in the public browser or connect with the public IP and configured port, then pass the version and mod checks. If it is listed but unreachable, concentrate on UDP forwarding, the firewall, the forwarding target, and NAT. If it is not listed at all, concentrate on Public visibility, credentials, the settings file actually being loaded, and startup errors.

Quick Recap

SaleBestseller No. 1

CyberPowerPC Gamer Xtreme VR Gaming PC, Intel Core i5-13400F 2.5GHz, GeForce RTX 5060 8GB, 16GB DDR5, 1TB PCIe 4.0 SSD, WiFi Ready & Windows 11 Home (GXiVR8060A40)

Graphics: NVIDIA GeForce RTX 5060 8GB Graphics | 1x HDMI | 2x DisplayPort; Tempered Side Case Panel | Custom RGB Lighting | Keyboard and Mouse

$1,282.00

Bestseller No. 2

ZER-LON Prebuilt Gaming PC Desktop, Core I7 up to 3.9 GHz, RX 550 4GB GDDR5

$469.99

SaleBestseller No. 3

Mumba Mouse Grip for Nintendo Switch 2 Joy-Con, [2 Pack] Ergonomic Gamer Grip Holder with Super Smooth PTFE Glide Pads Portable Gaming Controller Stand for Switch 2 Joy Con Accessories (2025), Black

$24.29

Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.

Dedicated ServersFactorioGame Serversheadless servermultiplayernetworkingport forwarding