Check if your Factorio server is online
Factorio is the exception here: we never contact your server directly. We ask Factorio's own matchmaking service what it knows about it.
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The ports Factorio uses
A Factorio server announces itself to the official public server list, and that entry is what we read. So the outcome depends on visibility settings, not on port forwarding. With `visibility.public` set to false, or without valid Factorio account credentials in its settings, a server is invisible here while running perfectly well and taking direct connections.
Every port a default Factorio install uses
With the game port left at 34197. If you changed it with --port, the other ports move with it.
| Port | What it is for |
|---|---|
| 34197 UDP | Game trafficRequired One UDP port, nothing else. Factorio is the simplest forward on this list. |
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Still offline? Try this
Before touching the router, check the visibility and credentials in server-settings.json. If the server is private on purpose, this check cannot see it and never will, and the TCP port tester cannot help either, because Factorio uses UDP only. The test that works for a private server is a real one: have someone outside your network join it by address.
What a Factorio server needs to run well
- Memory, 10 players
- 3 GB
- CPU cores
- 4+
- Disk
- 5 GB+
Update rate, not memory, is what fails first on a large factory. Single-thread clock is everything here.
Getting a server into the list
Public visibility needs two things in server-settings.json: visibility.public set to true, and a Factorio account to list the server under. The username goes in username, and for the credential use token rather than password; the token is on your profile at factorio.com or in player-data.json, and the settings file keeps credentials as plain text, so a token is the safer thing to leave lying there.
Testing a private server
A server kept off the public list on purpose will never show up here, because this check reads the list, not the server. The port tester on this site cannot stand in for it either: it tests TCP, and Factorio uses UDP only, so it reports 34197 closed even on a perfect setup. The complete test for a private server is a join from outside your network, using the server's public address.