Arma Reforger server config: examples, mods and ports

By Niko Catarino

Updated 2 October 2026

Check config.json before changing a Reforger installation that stopped after an edit. If the JSON parses, test an official scenario without mods using a separate profile. Preserve the live server’s configuration and saves while investigating.

For rented hosting, retain the assigned connection settings and use the host’s file controls. The Windows launch commands below apply when you manage the dedicated-server executable yourself.

Start with an unmodded example

Download the Conflict on Everon example and replace both password placeholders. Use different join and administrator passwords. Share the join password with players; keep the administrator password private.

{
  "bindPort": 2001,
  "publicPort": 2001,
  "game": {
    "name": "Reforger configuration test",
    "password": "REPLACE_WITH_YOUR_JOIN_PASSWORD",
    "passwordAdmin": "REPLACE_WITH_A_UNIQUE_ADMIN_PASSWORD",
    "scenarioId": "{ECC61978EDCC2B5A}Missions/23_Campaign.conf",
    "maxPlayers": 16,
    "visible": true,
    "crossPlatform": true,
    "gameProperties": {
      "fastValidation": true,
      "battlEye": true
    },
    "mods": []
  }
}

The resource path is Bohemia’s official Conflict on Everon entry. With crossPlatform enabled, Bohemia recommends omitting supportedPlatforms. Added mods and scenarios need their own console-compatibility checks. Keep fastValidation enabled for public servers. The example’s 16 players is a configuration value, not a measured capacity. Bohemia Server Config.

On a self-hosted setup using the same internal and external port, change both port fields together. On managed hosting, transfer the required game settings into a test copy of your assigned config and preserve provider-supplied fields and network values.

Check the file before restarting

Save the file as config.json. Strings need double quotes; numbers and true or false do not. A strict JSON parser rejects comments and trailing commas. With the Windows Python launcher installed, open PowerShell in that file’s directory and run:

py -m json.tool config.json > $null

Use the reported line and column to locate an error, then repeat the check after editing. Parsing covers syntax. It cannot validate Reforger fields, scenario resources or mod compatibility.

A trailing comma can prevent initialization with JSON parse error: Missing a name for object member. Keep the previous config before an edit so you can restore it without reinstalling the server.

Scalespeeder’s trailing-comma demonstration at 1:39 illustrates the fault. The local command above avoids uploading your config passwords to an online validator.

Confirm which config the server reads

For a Windows test installation you manage, create the directories in this command and save the edited file at its selected config path. Run from the server executable’s directory:

.\ArmaReforgerServer.exe -config "C:\ReforgerTest\config\config.json" -profile "C:\ReforgerTest\data" -maxFPS 60

Substitute your machine’s paths. -config selects the JSON, and -profile selects the profile location. Give the test a separate profile to keep it away from production saves. 60 caps FPS; it does not establish delivered performance. Bohemia Startup Parameters.

Do not add -server to this configuration-file test: that parameter loads a local world and ignores the JSON config. A world starting through it would not verify your selected file.

If a rented service has several configs, ask the host which one its launch settings select. A downloaded copy has no effect until the change reaches the active server file.

Add the scenario and its mod requirements together

Verify a player join on the base scenario before adding mods. In the PC Workshop mod manager, activate the intended set and export its entries from the JSON tab. Check the dependencies, then insert the entries into game.mods. Set game.scenarioId to the intended scenario’s complete .conf resource path. Mod entries need IDs rather than display names. Bohemia Server Config.

Record the versions from a working test. Omitting the optional version field selects the latest release; a later startup can therefore load changed content. Keep any version requirements from the mod author and test updates before applying them to production.

Scalespeeder’s restart-loop tutorial, published in May 2025, discusses dependencies and version choices. Recheck them against your installed release. Keeping an old working config does not freeze Workshop content whose versions it leaves unspecified.

Check ports for your hosting setup

Service	Documented default	Check
Player connection	UDP 2001	Compare with the assigned public game endpoint.
A2S queries	UDP 17777	Open the selected query port when using A2S.
RCON	UDP 19999	Use the selected port for restricted remote administration when needed.

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These are Bohemia’s defaults. Managed services can assign other ports. For self-hosting behind a router, match forwarding and the host firewall to the configured connection port, then test from another network. A localhost join alone cannot verify public reachability. Bohemia Server Hosting.

Match the symptom to the next check

Symptom	Next check
Failure after a JSON edit	Run the parser and compare the changed lines with your saved file.
JSON parses but the scenario fails	Read startup logs and verify the resource path and required mods.
Failure after adding mods	Restore the test’s previous set, then add one mod with its dependencies and test again.
Players cannot join	Compare game builds, admission settings, platform support and the assigned endpoint.
Incoming connection followed by authentication timeout	Retain client/server logs and check game/platform authentication and backend availability. The incoming connection alone cannot establish the cause or complete network reachability.
Mods download into an unexpected folder	Check the startup paths and the account running the process.

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-addonsDir changes where the process looks for mods. -addonDownloadDir selects the download destination, where the process creates an addons subfolder. Use startup parameters instead of adding invented fields to config.json. Bohemia Startup Parameters.

For a Windows test, choose the cache in the launch command:

.\ArmaReforgerServer.exe -config "C:\ReforgerTest\config\config.json" -profile "C:\ReforgerTest\data" -addonDownloadDir "C:\ReforgerTest\workshop-cache" -maxFPS 60

Confirm that the process account can write to the selected cache, then read the startup log for the download and load paths used by your installation.

Keep a recovery record

After a verified join, keep the config with its server build, scenario path, mod versions and startup log. Back up the save data you need. Preserve current files before a restore, then join and inspect the scenario afterward. Configuration rollback alone does not prove campaign-progress recovery.

For managed file access and configuration controls, review VYKIX Arma Reforger hosting.