How to Change the Map on an Arma Server

Changing the map — or terrain — on an Arma dedicated server is one of the most common configuration tasks server admins face. Whether you're running Arma 3, Arma Reforger, or an older title in the series, the process involves editing server configuration files and understanding how missions, terrains, and mods interact. It sounds straightforward, but the specifics vary depending on your server setup, the map you're switching to, and whether the terrain requires a mod to load.

What "Changing the Map" Actually Means in Arma

In Arma, the map (terrain) and the mission are closely linked. A mission is built on top of a specific terrain — you can't run a Chernarus mission on Altis without rebuilding it. So when most admins say they want to "change the map," they usually mean one of two things:

• Switching the active mission to one that uses a different terrain
• Replacing or rotating missions in the server's mission cycle so the map changes between sessions

The terrain itself is a separate asset. Some terrains are bundled with the base game (like Altis and Stratis in Arma 3), while others require Steam Workshop mods or DLC (like Tanoa, Livonia, or community maps like Chernarus 2020).

Step 1: Locate Your Server Configuration Files 🗂️

The two key files for most Arma 3 dedicated servers are:

• server.cfg — controls server name, password, mission rotation, and general settings
• mission.sqm — defines individual mission parameters (not edited directly to change maps)

For Arma Reforger, the equivalent is a JSON-based config file, but the logic is similar.

Open your server.cfg file with a plain text editor. Look for the Missions class block, which looks something like this:

class Missions { class Mission1 { template = "your_mission_name.Altis"; difficulty = "Regular"; }; }; 

The part after the dot — .Altis, .Stratis, .Tanoa — is the terrain identifier. This tells the server which map to load with that mission.

Step 2: Change the Mission Template

To switch to a different map, you replace the mission template entry with one that references a mission built on your target terrain.

For example, changing from Altis to Chernarus:

template = "my_mission.Chernarus"; 

Important: The mission file itself must exist in your server's MPMissions folder. The terrain name in the template string must exactly match the mission's folder name. If the file is named co_10_mission.Chernarus, the template entry must reflect that precisely, including capitalization.

Step 3: Handle Modded or DLC Terrains

If the map you're switching to is a community terrain (loaded via Steam Workshop) or a DLC terrain, there are extra steps:

For Workshop terrains, the mod folder must be listed in your server startup parameters using -mod= or -serverMod=. If clients are also required to have the mod, it needs to be in the regular -mod= parameter, not just server-side.

Forgetting to load the terrain mod is one of the most common reasons a server fails to load a new map — the mission template references a terrain the server simply doesn't have available.

Step 4: Upload the Mission File

Your new mission file (a .pbo file) needs to be placed in the correct directory on the server:

/arma3server/MPMissions/your_mission_name.TerrainName.pbo 

If you're running a hosted server through a game server provider (GSP), this is typically done via FTP/SFTP or their web file manager. If you're running a self-hosted server on Linux or Windows, you place the file directly in that folder.

Step 5: Restart the Server and Verify 🔄

After saving your server.cfg changes and confirming the mission file is in the right place, restart the server entirely — not just a mission vote or admin reload. A full restart ensures the new configuration is read cleanly.

Once the server is back online, check:

• The server browser listing shows the correct map name
• Players can connect without missing content errors
• The mission loads without crashing to lobby

If you see a "Mission file not found" or "Bad version" error, it usually means the template name doesn't match the file name exactly, or the terrain mod isn't loading.

Variables That Affect How This Process Works

The steps above cover the standard path, but several factors change the experience significantly:

• Server host type — Self-hosted servers give full file access; GSP-hosted servers may limit what you can edit directly
• Mod dependencies — Community terrains add mod management complexity, especially if clients need matching mods
• Arma version — Arma 3 vs. Reforger use different config formats and mod systems
• Mission availability — You need a mission file built for the target terrain, not just the terrain itself
• Server framework — If you're running ACE, ACRE, or a mission framework like ALiVE, switching maps may require additional mod config changes

A server running vanilla Arma 3 with base-game terrains has a much simpler process than one running a modpack with custom community maps and a persistent mission framework. The mechanics are the same — edit the config, place the file, load the mod — but the margin for error grows with each added layer.