How to host an Arma Reforger server (2026)

Short answer. You can host an Arma Reforger server yourself for free: install the dedicated server (Steam app 1874900) with SteamCMD and an anonymous login, write a config.json with a server name and a scenario, start ArmaReforgerServer with -config, and open UDP 2001. UDP 17777 (Steam queries) is optional. Or rent an Arma Reforger server and skip the networking.

Players find your server by name in the in-game server browser, or join it directly if you hide it from the list.

Checked on 5 November 2026 against Arma Reforger 1.8.0.13 (Steam update of 3 September 2026), the newest update Bohemia Interactive had announced on Steam.

This guide uses Bohemia Interactive's own server hosting documentation, the Steam announcements and what we run on every Arma Reforger server we host. To skip to the rental route, go to Option 2.

What you need

• The server software: the Arma Reforger dedicated server, Steam app 1874900 (stable). Bohemia lists a separate experimental server, app 1890870. It is free and downloads with +login anonymous. The game client, which players need, is a different Steam app.
• A machine that stays on: a spare PC, a home server or a cloud virtual machine. Bohemia does not publish a minimum server specification on its hosting page, and we give no RAM figure here. For sizing, read How much RAM does an Arma Reforger server need?
• Network: UDP 2001 for the game, reachable from the internet. Bohemia lists UDP 17777 (Steam query, A2S) and UDP 19999 (RCON) as optional ports. Bohemia's hosting page says a server is not reachable from outside until port forwarding is set up on your router.
• Operating system: Linux (Bohemia documents SteamCMD on Ubuntu) or Windows (ArmaReforgerServer.exe).
• The game: every player needs Arma Reforger.

The server software is free. You pay for the machine, power and bandwidth, not the software.

Option 1: host it yourself

The SteamCMD steps follow Bohemia's hosting page and Valve's SteamCMD page. The config keys are the ones our own servers use.

Linux (Ubuntu)

1. Install SteamCMD.

   sudo add-apt-repository multiverse
   sudo dpkg --add-architecture i386
   sudo apt update
   sudo apt install steamcmd

   On Debian, Valve's SteamCMD page says to enable the non-free repository instead of multiverse.
2. Download the server.

   /usr/games/steamcmd +force_install_dir /home/youruser/armar +login anonymous +app_update 1874900 validate +quit

   In our own installs, SteamCMD has sometimes finished without installing anything while still looking successful. Our install script therefore tries up to three times and only accepts the install when a file named appmanifest_*.acf exists in steamapps. Check for it yourself, and run the command again if it is missing. Also check that ArmaReforgerServer exists in the install folder.
3. Create the folders.

   cd /home/youruser/armar
   mkdir -p profile tmp

4. Write config.json in that folder. This is the shape we use:

   {
     "bindAddress": "0.0.0.0",
     "bindPort": 2001,
     "publicPort": 2001,
     "a2s": {
       "address": "0.0.0.0",
       "port": 17777
     },
     "game": {
       "name": "My Arma Reforger Server",
       "password": "",
       "passwordAdmin": "choose-an-admin-password",
       "admins": [],
       "scenarioId": "{ECC61978EDCC2B5A}Missions/23_Campaign.conf",
       "maxPlayers": 32,
       "visible": true,
       "gameProperties": {
         "disableThirdPerson": false,
         "fastValidation": true,
         "battlEye": true
       },
       "mods": []
     }
   }

   An empty password means anyone can join. Bohemia notes that the admin password cannot contain spaces. The a2s block is optional: it makes the server answer Steam query (A2S) requests on UDP 17777, and you can leave it out. Do not put a double quote or a backslash in the name or passwords unless you escape it, because the game cannot parse a broken file. The scenario above is the Conflict - Everon scenario our servers start with.
5. Start the server.

   chmod +x ArmaReforgerServer
   ./ArmaReforgerServer -gproj ./addons/data/ArmaReforger.gproj -config ./config.json -profile ./profile -backendlog -nothrow -listScenarios -maxFPS 120 -addonTempDir ./tmp

   -maxFPS matters: Bohemia's page says to set it between 60 and 120, because otherwise the server can try to use all the available resources. -listScenarios prints the scenario IDs your server can load, so you can pick another scenarioId. Logs and downloaded mods go in the profile folder.
6. Open the ports. Allow UDP 2001 on the machine's firewall (with ufw: sudo ufw allow 2001/udp), plus UDP 17777 if you kept the a2s block (sudo ufw allow 17777/udp), then forward the same UDP ports on your router to this machine.
7. Keep it running. Bohemia's page suggests a systemd service that runs a start script and restarts after crashes, and mentions LinuxGSM as a monitoring and update tool. The server does not update itself: run the SteamCMD command again after a game update.

Windows

1. Download SteamCMD from https://client-update.steamstatic.com/installer/steamcmd.zip and extract it to a folder such as C:\steamcmd.
2. In a Command Prompt:

   cd C:\steamcmd
   steamcmd +force_install_dir C:\ArmaReforgerServer +login anonymous +app_update 1874900 validate +quit

3. Write config.json as in the Linux step 4, then start the server with ArmaReforgerServer.exe -config ".\config.json" -profile ".\profile" -maxFPS 120.
4. Allow UDP 2001 (and UDP 17777 if you kept the a2s block) inbound in Windows Firewall and forward the same ports on your router.

Adding Workshop mods

Arma Reforger fetches its own mods. Put each mod in the mods array of config.json with its 16 character Workshop ID, for example {"modId": "591AF5BDA9F7CE8B"}, and the server downloads it when it starts and sends it to players as they join. Add "version": "1.2.0" next to modId to hold a mod at one release. Mods are covered in How to add mods to your Arma Reforger server.

Option 2: host it on PlayNHost

Renting removes the firewall, port forwarding and update routine. The ports, the query block and the config file are set up for you.

1. Pick a plan. Open the Arma Reforger server hosting page and compare the plans (SERGEANT, LIEUTENANT and COLONEL at the time of writing). Press Create Server on SERGEANT or LIEUTENANT, or Customize Plan on COLONEL, and finish the order. Prices change, so check them on that page.
2. Wait for the install. You get a "server ready" email and the server appears at panel.playnhost.com. On the Console tab, the panel counts the server as running when it prints Starting RPL server.
3. Open Settings, then Game Settings. These fields are written into config.json each time the server starts:
   • Server Name: the name shown in the in-game server browser.
   • Server Password: the password players enter to join. Leave it empty for an open server.
   • Admin Password: join the server and type #login followed by this password in chat to get admin rights. Leave it empty for no admin login.
   • Scenario ID: the scenario the server loads. The full list of IDs available to your server is printed in the console each time it starts.
   • Max Players: the player limit included with your plan.
   • Visible in Server Browser: turn it off and players join by direct connect.
   • Disable Third Person and Enable BattlEye: third person is allowed and BattlEye is on by default.
   • Steam Query Port: shown for reference. The panel assigns it with your server and it cannot be changed from this page.
   Under Show advanced, Automatic Updates is on by default and checks Steam for a game update each time the server starts.
4. Restart. Press Restart now when the panel offers it and wait for Starting RPL server in the console.
5. Add Workshop mods (optional). Open the Modding tab and list the mod IDs under Workshop mods, then press Restart to apply. Clearing the list puts the server back on the stock game at the next start.
6. Join. Find your server name in the in-game server browser and enter the password, unless you left it empty. More detail: How to join your Arma Reforger server.

What the panel does for you

• The ports. At every start the panel writes your game port and query port into bindPort, publicPort and a2s, so the server answers Steam query (A2S) requests on its own assigned port.
• Public address. We leave publicAddress out of the file on purpose. Filled in with the address the server binds to (0.0.0.0), the server registered itself with that address and showed an unknown ping. Left out, Reforger detects its real public address.
• Keys the panel owns. The server name, both passwords, scenario, player count, visibility, third person, BattlEye and the ports are rewritten from Game Settings at every start, so hand edits to those keys in config.json do not last. Other keys, such as admins and the view distances, are left alone. You can edit them under Files: stop the server first, then start it again.
• Safe values. Server name, passwords and scenario ID cannot contain a double quote or a backslash, so a typo cannot break config.json.
• Mods. A startup script fills the mods array from Workshop mods after the panel rewrites the file. Only that array is replaced. A malformed mod ID makes it skip the change and print a message in the console instead of failing to start.
• Install retries. The install tries SteamCMD up to three times and stops with an error if the server files are missing, instead of continuing on an empty folder.
• Backups. If your plan includes backups, take one from Backups before editing the config by hand.

Self-hosting or renting: an honest comparison

• Cost. Self-hosted: the software is free, and you pay for hardware, power and bandwidth, or a cloud virtual machine. Rented: a monthly fee set by plan. See the current plans.
• Availability. Self-hosted: as reliable as your machine, power and home internet, and it has to stay on when your friends play. Rented: runs on the host's hardware, not your PC.
• Network exposure. Self-hosted: players connect to your public IP, and you look after the firewall and router. Rented: your home IP is not involved.
• Skill needed. Self-hosted: command line, port forwarding, JSON editing and an update routine. Very doable, and a good way to learn. Rented: a web panel with form fields.
• Updates. Self-hosted: run SteamCMD again after a game update, then start the server. Rented: Automatic Updates installs a new build when the server starts, so press Restart after a patch.
• Control. Self-hosted: you can edit anything. Rented: the keys the panel owns are changed in Game Settings, and the rest of the file stays editable.

Self-hosting suits you if a machine already runs all day and you are comfortable with networking. Renting suits you if you would rather not look after hardware.

Common problems and fixes

The server runs but is not in the server browser

Cause: visible is set to false, or publicAddress holds an address players cannot reach.

Fix: set "visible": true, and remove publicAddress so the backend detects your public address, as Bohemia recommends. Check that UDP 2001 is forwarded, then restart. On PlayNHost, turn on Visible in Server Browser. See also Arma Reforger server problems and fixes.

Players cannot connect from outside your network

Cause: port forwarding is missing. Bohemia's page says a hosted server is not reachable from the internet until the router forwards the ports.

Fix: forward UDP 2001 to the server machine, plus UDP 17777 if you use the a2s block.

Players cannot join after a game update

Cause: a self-hosted server does not update itself, so it can fall behind the game version players run.

Fix: run the SteamCMD command again and restart. On PlayNHost, restart with Automatic Updates on.

The server uses far more CPU than expected

Cause: -maxFPS is not set. Bohemia warns the server can then try to use all the available resources.

Fix: start with -maxFPS 120, or a value between 60 and 120.

The server will not start after a config edit

Cause: a double quote or backslash in a name or password, or any other invalid JSON, breaks config.json.

Fix: escape or remove the character and restart. On PlayNHost the panel refuses those characters in Game Settings.

Your changes to config.json disappear (PlayNHost)

Cause: the key is one the panel writes at every start.

Fix: change the name, passwords, scenario, player count and visibility in Game Settings, and mods under Workshop mods. For the full list of keys, see Arma Reforger server settings: every option explained.

FAQ

Can I host an Arma Reforger server for free?

Yes. The dedicated server is free on Steam (app 1874900) and downloads with an anonymous login. You still pay for the machine, power and internet, and it must stay on while people play.

Which ports does an Arma Reforger server use?

UDP 2001 for the game, and it must be reachable from the internet. Bohemia lists UDP 17777 (Steam query, A2S) and UDP 19999 (RCON) as optional, needed only if you turn those features on.

Do I need to own the game to run the server?

Not to install it. Players need the game to join.

Can I run mods?

Yes. List Workshop mod IDs in the mods array, or on PlayNHost under Workshop mods on the Modding tab. The server downloads them and sends them to players as they join.

How do I become admin?

Set an admin password, join the server and type #login followed by the password in chat. More in How to become admin on your Arma Reforger server and use admin commands.

Ready to skip the setup? See the Arma Reforger server plans.