Learn how to install and manage mods on your Arma 3 dedicated server. This guide covers Steam Workshop mods, manual installation via SFTP, load order, and signature verification. For initial server configuration, see our Server Setup Guide. For admin tools and anti-cheat, see Admin and BattlEye Setup.

Understanding Arma 3 Mods

Arma 3 mods come in two forms:

• Client-side mods (loaded with -mod=): Required by both the server and all connecting players. Players must have these mods installed and enabled in their Arma 3 launcher to join. Examples: CBA_A3, ACE3, RHS, terrain mods.
• Server-side mods (loaded with -serverMod=): Only required on the server. Players do not need to download or enable these. Examples: admin tools, logging frameworks like OCAP2, server-side AI enhancement mods.

Steam Workshop Mods

The easiest way to add mods is through the Steam Workshop. Each Workshop mod has a unique Mod ID (the number in its Steam Workshop URL).

Finding Mod IDs

Navigate to the mod's Steam Workshop page. The URL will look like:

https://steamcommunity.com/sharedfiles/filedetails/?id=463939057

The mod ID in this example is 463939057 (this is CBA_A3). Here are IDs for commonly used mod frameworks:

Adding Mods via GPanel Startup Variables

Depending on your server's egg configuration, you may be able to enter Workshop mod IDs directly in the GPanel Startup tab. Check for variables like MODS or WORKSHOP_MODS.

For the MODS variable, enter mod folder names separated by semicolons:

@CBA_A3;@ace;@ACRE2

Downloading and Uploading Mods via SFTP

For manual mod installation (or if your server egg does not support automatic Workshop downloads), you can download mods locally and upload them via SFTP.

Step 1: Download Mods Locally

1. Open your Arma 3 Launcher on your PC.
2. Go to the Mods tab and subscribe to the mods you want on your server.
3. Let them download. By default, mods are stored in your Arma 3 directory under a folder named with the Workshop ID, typically:
   C:\Program Files (x86)\Steam\steamapps\common\Arma 3\!Workshop\
   or in the Workshop content folder:
   C:\Program Files (x86)\Steam\steamapps\workshop\content\107410\

Step 2: Prepare Mod Folders

1. Copy each mod folder and rename it to a clean format (e.g., @CBA_A3, @ace). Mod folders should start with @.
2. Rename all files and folders inside the mod to lowercase. This is critical for Linux-based servers. You can use a tool or script to batch-rename, or do it manually. Specifically, the addons/ folder and all .pbo and .bisign files inside must be lowercase.

Step 3: Upload via SFTP

1. Connect to your server via SFTP using the credentials from GPanel (see SFTP Upload Guide).
2. Upload each mod folder (e.g., @CBA_A3, @ace) to the root of your Arma 3 server directory.
3. Update the MODS startup variable in GPanel to include the new mod folder names.

Mod Loading Order

Load order matters in Arma 3. Dependency mods must be loaded before mods that depend on them. The order is determined by the sequence in your -mod= parameter or MODS startup variable.

General loading order rules:

1. CBA_A3 — always first, as nearly every other mod depends on it.
2. Content/asset mods — RHS, CUP, Global Mobilization, terrain mods.
3. Framework mods — ACE3, ACRE2/TFAR.
4. Compatibility/patch mods — ACE3-RHS compatibility patches, etc.
5. Mission-specific mods — other addons required by your specific missions.

Example of a properly ordered mod string:

@CBA_A3;@rhsafrf;@rhsusaf;@rhsgref;@rhssaf;@ace;@ace_compat_rhs_afrf3;@ace_compat_rhs_usf3;@ace_compat_rhs_gref3;@acre2

Keys and Bikeys for Signature Verification

Arma 3 uses a signature verification system to ensure that clients are running the same mod versions as the server. This prevents modified or tampered PBOs from being used.

How It Works

• Each mod contains .bisign files (signatures) alongside its .pbo addon files.
• Each mod also includes a .bikey (public key) file, usually found in the mod's keys/ or Keys/ subfolder.
• The server checks connecting clients' mod files against these signatures.

Installing Keys

1. Navigate to each mod's folder and locate the .bikey file(s). They are typically in a keys/ or Keys/ subfolder within the mod directory.
2. Copy all .bikey files to the server's keys/ directory (in the root of your Arma 3 server installation).
3. Ensure verifySignatures = 2; is set in your server.cfg to enforce signature checking.

// Example: keys directory structure
/keys/
    a3.bikey           (vanilla Arma 3 key - do NOT remove)
    cba_a3.bikey
    ace3.bikey
    rhsafrf.bikey
    rhsusaf.bikey
    acre2.bikey

Popular Mod Frameworks

CBA_A3 (Community Base Addons)

The foundational mod for the Arma 3 modding community. Almost every major mod requires CBA_A3 as a dependency. It provides shared functions, keybinding framework, extended event handlers, and settings framework. Always install this first.

ACE3 (Advanced Combat Environment)

The most widely used milsim overhaul mod. Features include:

• Advanced medical system (basic and advanced modes)
• Realistic ballistics and fragmentation
• Advanced interactions (carrying, dragging, rope systems)
• Vehicle and weapon systems overhauls
• Extensive server-side configuration via CBA settings

ACE3 settings can be configured server-side by editing userconfig/ace/serverconfig.hpp or through CBA's addon settings (persisted in the server profile).

ACRE2 / TFAR (Radio Mods)

Both provide realistic radio communication integrated with TeamSpeak 3. Players must install a TeamSpeak plugin on their end. Choose one or the other — they are not compatible with each other.

• ACRE2: More realistic simulation, positional audio, signal propagation affected by terrain.
• TFAR: Simpler setup, widely used in public communities, slightly less realistic.

RHS (Red Hammer Studios)

A collection of four mods adding highly detailed real-world military assets (vehicles, weapons, uniforms) for Russian, US, guerrilla, and Serbian factions. Total download size is approximately 15-20 GB across all four modules.

Troubleshooting Mod Issues

Related Articles

• Arma 3 Server Setup Guide — Initial server setup, server.cfg, difficulty settings, and mission rotation.
• Arma 3 Admin and BattlEye Setup — Configure admin access, BattlEye anti-cheat, and RCON tools.
• How to Find Your Server IP and Port
• How to Upload Files via SFTP
• Getting Started with Your New Server

Need Help?

Running into issues with your mods or need help with a complex modpack setup? Open a support ticket and our team will assist you.