How to Install Mods on Your Arma 3 Server

In Arma 3, mods are folders in the main directory of your server and always start with an @ – for example @cba_a3. They are loaded through two start parameters that you set through the corresponding fields in the dashboard.

Parameter	Meaning
`-mod=`	Client mods. All players need to have these mods installed and enabled in their launcher as well.
`-serverMod=`	Server mods. They run on the server only and do not have to be installed by players.

In both cases you separate multiple mods with a semicolon:

@cba_a3;@ace;@operation_trebuchet

Important

Your server runs on Linux, and Linux is case sensitive. Therefore rename every mod folder to all lowercase and remove spaces and special characters – underscores are allowed. So @Operation TREBUCHET becomes @operation_trebuchet. The same applies to the .pbo files inside the addons subfolders. Folder names starting with a number do not work reliably either.

Method 1: Export a mod list from the launcher

With this method your server downloads the mods from the Steam Workshop itself. It is the easiest way for Workshop mods.

Start the Arma 3 launcher
Start Arma 3 via Steam so the launcher opens and switch to the Mods tab.
Enable the mods
Enable all mods that should run on your server. Make sure required dependencies such as @CBA_A3 are enabled too.
Export the mod list
Export the active mod list as an HTML file to your PC using the launcher's preset function.
Stop the server
Stop your server via the dashboard.
Upload the file
Connect to your server via SFTP and upload the file as modlist.html into the main directory:
```
/modlist.html
```
Enter the mod list
Open the settings in your dashboard and enter the file name in the field for the mod list file. By default it already says modlist.html.
Start the server
Start your server. The mods from the list are downloaded on startup – depending on their size this can take a few minutes.

Steam account required

For the automatic Workshop download your server needs the credentials of a Steam account that owns Arma 3. Anonymous downloads are not possible for Workshop content. You store the credentials in the settings of your dashboard.

Method 2: Enter Workshop IDs directly

Instead of a mod list you can also specify mods individually by their Workshop ID.

Copy the Workshop ID
Open the mod page in the Steam Workshop. The ID is the number at the end of the address, for example 450814997 in .../filedetails/?id=450814997.
Stop the server
Stop your server via the dashboard.
Enter the IDs
Enter the IDs in the settings in the field for the mods – each with a leading @ and separated by semicolons:
```
@450814997;@463939057;
```
Server mods go into the field for server mods instead.
Start the server
Start your server. The mods are downloaded on startup.

Note

Whether your server downloads mods from the Workshop ID alone depends on its configuration. If the matching mod folders are not created on startup, use method 1 instead or upload the mods manually as described in method 3.

Method 3: Upload mods manually

You need this method for mods that do not come from the Workshop.

Subscribe to the mod
Subscribe to the mod in the Steam Workshop and start Arma 3 once so it gets downloaded.
Open the mod folder
You find the subscribed mods on your PC under:
```
...\Steam\steamapps\common\Arma 3\!Workshop
```
Rename the folder
Rename the mod folder to all lowercase and replace spaces with underscores, for example @operation_trebuchet. Also rename the .pbo files in the addons subfolder to lowercase.
Pack the folder
Pack the mod folder into a .zip file.
Stop the server
Stop your server via the dashboard.
Upload and extract
Connect via SFTP, upload the archive into the main directory of your server and extract it there. Afterwards the mod folder has to sit directly in the main directory:
```
/@operation_trebuchet
```
Caution
Arma 3 only loads mods from the main directory of the server and its subfolders. Folders outside of it are not recognized.
Copy the key
Open the keys (or key) subfolder of the mod and upload the .bikey file it contains into the /keys folder of your server.
Enable the mod
Enter the folder name in the settings in the field for the mods – separate multiple entries with semicolons:
```
@cba_a3;@operation_trebuchet
```
Start the server
Start your server.

Verify signatures

To make sure only players with unmodified mod files can join your server, Arma 3 verifies the signatures of the mods. For this, the .bikey of every mod has to be in the /keys folder. In Arma 3 the verification is enabled by default – when in doubt, check whether the value is set in your server.cfg.

Stop the server
Stop your server via the dashboard.
Open the server.cfg
Open the file /server.cfg via SFTP.
Enable signature verification
Enter the following value:
```
verifySignatures = 2;
```
Start the server
Save the file and start your server.

Note

With signature verification enabled, server mods loaded through -serverMod= do not have to be installed by players. Mods without a .bikey file can only be loaded as server mods.

Troubleshooting

Problem	Solution
Server does not start	Check that all mod folders are named exactly as entered in the settings – including lowercase spelling
Mod is not loaded	Check that the folder sits directly in the main directory and starts with `@`
Players are rejected when joining	All client mods have to be active on the players' side in the same version
Signature error	Check that the matching `.bikey` file of every mod is in the `/keys` folder
Mods missing after startup	Check that a Steam account owning Arma 3 is stored in the settings

How to Install Mods on Your Arma 3 Server ​

Method 1: Export a mod list from the launcher ​

Method 2: Enter Workshop IDs directly ​

Method 3: Upload mods manually ​

Verify signatures ​