How to Host an Arma 3 Server

Hosting your own Arma 3 server gives you full control over missions, mods, and player slots, and it is the only way to run persistent, community-style gameplay without paying a hosting company. This guide walks you through setting up a dedicated server on Windows, from downloading the files to connecting your friends. You do not need any prior server experience, but you will need a copy of Arma 3 (for the server files), a PC that can run the server, and a stable internet connection with a public IP or port forwarding access.

What You’ll Need

A PC running Windows 10/11 (or a Linux VPS if you prefer, but this guide is Windows-focused)
An Arma 3 copy on Steam (the server files are free via SteamCMD, but you need the game for testing)
SteamCMD – a free command-line tool from Valve to download the dedicated server files
Port forwarding access on your router (if hosting for others over the internet)
Optional: a text editor like Notepad++ for editing config files

Step-by-Step

Download SteamCMD. Go to the official SteamCMD page on Valve’s developer wiki and download the Windows zip. Extract it to a folder like C:\steamcmd.
Run SteamCMD. Open a command prompt (Win+R, type cmd, Enter) and navigate to the folder where you extracted SteamCMD. Run steamcmd.exe. It will update itself on first run.
Log in anonymously. At the Steam> prompt, type login anonymous. You do not need a Steam account for the server files.
Set the install directory. Type force_install_dir C:\arma3server (or any path you want). This tells SteamCMD where to put the server files.
Download the server files. Type app_update 233780 validate. This is the Arma 3 dedicated server app ID. Wait for the download to finish – it is about 5 GB.
Exit SteamCMD. Type quit and close the window.
Create a server config file. In the server folder, create a text file named server.cfg. Open it in a text editor and add at minimum:
```
hostname = "My Arma 3 Server";
password = "";
passwordAdmin = "admin123";
maxPlayers = 16;
```
Save it.
Create a basic mission file (optional). If you want a simple deathmatch, copy the MPMissions folder from your Arma 3 installation (e.g., C:\Program Files (x86)\Steam\steamapps\common\Arma 3\MPMissions) to the server folder. Or download a mission from the Steam Workshop and place it in MPMissions.
Launch the server. In the server folder, run arma3server.exe with parameters. A basic command line is:
```
arma3server.exe -config=server.cfg -port=2302 -name=Server1
```
Keep the window open – it will show the server log.
Test locally. Open Arma 3 on the same PC, go to Multiplayer > Direct Connect, enter 127.0.0.1:2302, and join. If you can join, the server works.
Port forward (for internet play). Log into your router’s admin page (usually at 192.168.1.1 or 192.168.0.1). Find Port Forwarding or Virtual Server. Forward UDP ports 2302-2305 and TCP 2302-2305 to your PC’s local IP address. Also forward UDP 8766 and 27016 for Steam query. Save and reboot the router.
Find your public IP. Search “what is my IP” on Google, note the address, and share it with friends. They connect via yourIP:2302.
Keep the server running. You can close the console window to stop the server. To run it in the background, use a batch file or a service wrapper, but for a small group the console window is fine.

Common Mistakes

Using the game’s app ID instead of the server’s. The server is app 233780, not the game’s 107410.
Forgetting to forward UDP. Arma 3 uses UDP primarily; TCP alone will not work.
Wrong port in the join address. The default is 2302, but if you changed it, you must include the new port.
Server config syntax errors. A missing semicolon can crash the server on startup. Use a config checker or validate with the community tools.
Not allowing the server through Windows Firewall. Windows will block incoming connections by default; add an exception for arma3server.exe on the ports you use.

Tips

Use a static IP for your PC on the local network so port forwarding does not break after a DHCP lease renewal.
For mods, use the Steam Workshop: subscribe to mods in the game, then copy the @modname folders from your Arma 3 directory to the server, and add -mod=@modname to the launch parameters.
Set a passwordAdmin and use it in-game to kick/ban players via the admin menu.
Monitor server performance: if FPS drops below 20, reduce maxPlayers or lower view distance.
Back up your server.cfg and mission files – they are small but easy to lose.

Troubleshooting

Server crashes on startup. Check the server console log for errors. Most often it is a syntax error in server.cfg – open it and verify every line ends with a semicolon. Also ensure the path in force_install_dir exists.

Players cannot connect from the internet. First, test locally. If local works, the issue is port forwarding or firewall. Double-check that you forwarded UDP 2302-2305 to the correct local IP. Use an online port checker to see if the port is open. Also make sure your ISP does not block inbound connections (some do).

Server shows in LAN but not internet. This is usually a Steam query port issue. Forward UDP 8766 and 27016. Also add -port=2302 to the launch parameters explicitly.

Players get “Connection failed” after joining. This can be a mod mismatch. Ensure both server and clients have the same mods loaded, and check the server log for missing addon errors.

Server runs but is very laggy. Reduce the number of AI units in your mission, lower maxPlayers, and close other programs on the host machine. Also check your upload bandwidth – Arma 3 servers need about 1 Mbps per 10 players.

Frequently Asked Questions

Q: Do I need to buy Arma 3 to host a server?
A: No. The dedicated server files are free via SteamCMD. You only need the game to test the server locally.

Q: Can I host on Linux?
A: Yes, Arma 3 has a Linux server binary, but the setup is more complex. This guide covers Windows, but the SteamCMD commands are the same on Linux.

Q: How many players can I host?
A: It depends on your CPU and internet speed. A typical home connection can handle 10-20 players. The server itself can support up to 64 or more, but your hardware is the limit.

Q: How do I add mods to my server?
A: Download the mods to the server’s @modname folder, then add -mod=@modname to the launch parameters. Ensure all clients have the same mods.

Q: Can I run the server without Steam running?
A: Yes, the dedicated server does not require the Steam client to be running. It uses SteamCMD only for downloading files.

Q: How do I update the server?
A: Run SteamCMD again and execute app_update 233780 validate. This will update the server files to the latest version.

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.

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