How to Install an Arma 3 Server

This guide shows you step by step how to set up an Arma 3 Dedicated Server – both on Windows and Linux. Arma 3 is known for its high CPU usage, so the right configuration is crucial.

Requirements

• Operating system: Windows 10/11 (64-bit) or Windows Server 2019/2022; Linux (Ubuntu 20.04/22.04, Debian 11/12)
• CPU: 4 cores with high clock speed (3.5 GHz+), strong single-core performance crucial
• RAM: At least 8 GB, 16 GB recommended (especially with mods)
• Storage: 50 GB free SSD storage (100 GB+ with mods)
• Network: UDP ports 2302-2306 must be open
• Steam account: A Steam account with Arma 3 is required for the download

Linux or Windows?

Windows is often recommended for Arma 3 servers as it runs more stable and has fewer compatibility issues with mods. Linux is more resource-efficient and free, but can cause problems with some mods. Many community servers use Windows Server.

Step 1: Install SteamCMD and download the server

Windows

1. Create two folders:

   C:\SteamCMD
   C:\arma3server

2. Download SteamCMD from the official Valve website and extract it to C:\SteamCMD
3. Run steamcmd.exe. In the SteamCMD window enter:

   login YourSteamUsername
   force_install_dir "C:\arma3server"
   app_update 233780 validate
   quit

Linux

1. Create a new user for the server (security):

   sudo useradd -m -s /bin/bash steam
   sudo passwd steam
   su - steam

2. Install SteamCMD:

   mkdir ~/steamcmd && cd ~/steamcmd
   wget http://media.steampowered.com/installer/steamcmd_linux.tar.gz
   tar -xvzf steamcmd_linux.tar.gz

3. Run SteamCMD and download the server:

   ./steamcmd.sh
   login YourSteamUsername
   force_install_dir ./arma3/
   app_update 233780 validate
   exit

Step 2: Create server.cfg

Create the file server.cfg in the server's main directory with the following content:

// GENERAL
hostname = "My Arma 3 Server";     // Name in the server list
password = "";                      // Player password (empty for public)
passwordAdmin = "MyAdminPassword";  // Admin password
maxPlayers = 32;                    // Maximum number of players

// SECURITY
verifySignatures = 2;               // 2 = strict mod verification
battleye = 1;                       // 1 = BattlEye enabled

// VOTING
voteMissionPlayers = 1;             // 1 = players can vote missions

// MISSIONS
class Missions {
    class MyMission {
        template = "MyMission.Altis";
        difficulty = "Veteran";
    };
};

Step 3: Create basic.cfg

This file controls network performance. Create basic.cfg in the same folder:

language = "English";
adapter = -1;
3D_Performance = 1.000000;
Resolution_W = 800;
Resolution_H = 600;
Resolution_Bpp = 32;

MinBandwidth = 131072;
MaxBandwidth = 104857600;
MaxMsgSend = 256;
MaxSizeGuaranteed = 512;
MaxSizeNonguaranteed = 256;
MinErrorToSendNear = 0.029999999;
MinErrorToSend = 0.003;
MaxCustomFileSize = 0;
Windowed = 0;
serverLongitude = 10;
serverLatitude = 51;

Step 4: Start the server

Windows – Create startup file

Create a start.bat in the server folder:

@echo off
set PORT=2302
set CONFIG=server.cfg
set BASIC=basic.cfg
set PROFILE=serverProfile

arma3server_x64.exe ^
 -port=%PORT% ^
 -config=%CONFIG% ^
 -cfg=%BASIC% ^
 -name=%PROFILE% ^
 -profiles="C:\arma3server\profiles" ^
 -autoInit
pause

Linux – Start command

cd ~/arma3
./arma3server -name=server -config=server.cfg -cfg=basic.cfg -port=2302

Step 5: Open firewall ports

The following UDP ports must be open:

• UDP 2302 – Game port (main connection)
• UDP 2303 – Steam Query
• UDP 2304 – Voice
• UDP 2305-2306 – Additional ports

Windows Firewall (PowerShell as Administrator)

New-NetFirewallRule -DisplayName "Arma 3 Server" -Direction Inbound -Protocol UDP -LocalPort 2302-2306 -Action Allow

Linux (UFW)

sudo ufw allow 2302:2306/udp

Then forward the ports in your router to your server's local IP address.

Step 6: Set up mods (optional)

1. Download mods from the Steam Workshop
2. Copy the mod folders (starting with @) into your server directory
3. Copy the .bikey files of the mods into the keys/ folder
4. Modify your start.bat to load the mods:

   "-mod=@cba_a3;@ace;@rhsafrf"

Step 7: Join the server

1. Launch Arma 3 on your PC
2. Go to the server browser
3. Filter by "Internet" or use "Direct Connect"
4. Enter your server IP and port (e.g. 123.123.123.123:2302)
5. Enter the server password (if set)

Hardware recommendations

Common problems

• Server not showing in the list: Check port 2303 (Steam Query) and firewall
• Connection problems: Check if you're behind CGNAT – then public access is not possible
• Mod mismatch: verifySignatures = 2 checks mod signatures – all players need the same mods
• Server crashes: Check if DirectX and all VC++ Redistributables are installed
• High CPU load: Reduce AI count in missions or use headless clients