ThisCalculator

Everyday

Host Arma 3 Server Without Port Forwarding

Updated · Standard formula, shown below

Host Arma 3 Server Without Port Forwarding

This guide shows you how to host an Arma 3 multiplayer server without opening or forwarding any ports on your router. It uses a free VPN tunnel service (like Radmin VPN or ZeroTier) to create a virtual LAN between you and your friends, so the game thinks you’re all on the same local network. You’ll need the Arma 3 server files (free on Steam), a Windows PC, and your friends to install the same VPN software.

What You’ll Need

  • A Windows PC (the host) with Arma 3 installed (the game itself is required to download server files).
  • Steam account with Arma 3.
  • Free VPN software: Radmin VPN or ZeroTier (both free for personal use).
  • Your friends also need the same VPN software installed.
  • Basic knowledge of Windows file explorer and text editing.

Step-by-Step

  1. Install the VPN software (host and all players). Download and install Radmin VPN (or ZeroTier). Create a free account if required. For Radmin, after installation, you’ll see a window with your virtual IP address (e.g., 26.x.x.x).
  2. Create a virtual network. In Radmin VPN, click “Create Network”. Give it a name and a password. Share this network name and password with your friends. They click “Join Network” and enter the details. In ZeroTier, create a network on their website, note the Network ID, have friends join it, and you approve their join requests in the ZeroTier dashboard.
  3. Download the Arma 3 server files. On the host PC, open Steam, go to Library, and filter by “Tools”. Find “Arma 3 Server” and install it. It will download to a folder like steamapps/common/Arma 3 Server.
  4. Create a basic server configuration file. Navigate to the Arma 3 Server folder. Create a new text file named server.cfg. Open it with Notepad and paste the following minimal config: 
    hostname = "My VPN Server";
password = "";
passwordAdmin = "admin123";
maxPlayers = 16;

    Save the file. You can change the hostname and admin password later.

  5. Create a launch shortcut. In the same folder, right-click on arma3server.exe, select “Send to” > “Desktop (create shortcut)”. Right-click the shortcut, choose “Properties”, and in the “Target” field add the following after the existing path (inside the quotes): 
    -config=server.cfg -port=2302 -name=server

    So it looks like: "C:\...\arma3server.exe" -config=server.cfg -port=2302 -name=server. Click OK.

  6. Start the server. Double-click the shortcut. A command prompt window will open. Wait until you see a message like “Game server started” or “Host created”. Do not close this window.
  7. Find your virtual IP. In Radmin VPN, your virtual IP is shown in the main window. In ZeroTier, find it in the ZeroTier client (usually under “Managed IPs”). Note it down, e.g., 26.0.0.1.
  8. Connect from the game. On your friends’ PCs, launch Arma 3. Go to “Multiplayer”, then “Direct Connect”. Enter the host’s virtual IP followed by the port, like 26.0.0.1:2302. Click “Connect”. They should join your server.
  9. Test locally. To test yourself, on the host PC, also use Direct Connect with your virtual IP and port, or use “LAN” tab and you should see your server there.

Common Mistakes

  • Not using the same VPN network. Everyone must be on the same virtual network. Double-check the network name/password.
  • Forgetting the port in the connection string. If you don’t specify the port, Arma defaults to 2302, but if you changed it, you must include it.
  • Firewall blocking the server. Windows Firewall may block arma3server.exe. When you first run it, allow access on both Private and Public networks. If you already blocked it, go to Windows Security > Firewall & network protection > Allow an app through firewall, and add arma3server.exe.
  • Using the wrong IP. Don’t use your public IP or local 192.168.x.x. Use the virtual IP from the VPN software.
  • Server not starting due to missing files. Ensure you downloaded the server via Steam Tools, not just the game. The server files are separate.

Tips

  • Use a static virtual IP. In Radmin VPN, you can set a static IP for your host machine to avoid IP changes. Right-click your computer name in Radmin, go to Properties, and set a static IP.
  • Keep the server window open. Minimize it, but don’t close it. Closing the window stops the server.
  • Add mods later. To add mods, you need to use the -mod=@mod1;@mod2 parameter in the shortcut and place mods in the server folder. This is advanced but works the same way.
  • Set a server password. Change the password in server.cfg to prevent randoms from joining if they somehow find your network.
  • Use a dedicated machine. Hosting on the same PC you play on can cause lag. If possible, use a separate PC or at least close other heavy applications.

Troubleshooting

Friends can’t see the server in LAN tab. They should use Direct Connect with the virtual IP, not rely on the LAN tab. The LAN tab sometimes doesn’t refresh automatically.

Connection times out. Check that the server is running (window open). Verify everyone is on the same VPN network. Check Windows Firewall on the host – allow arma3server.exe on Private and Public. Also, try disabling Windows Firewall temporarily to test (re-enable after).

Server crashes on start. Look at the command prompt output. Common issues: missing server.cfg, incorrect path in the shortcut, or missing SteamCMD files. Re-download the server files if needed.

Players get kicked instantly. This often means they are not on the same VPN network. Double-check their VPN connection and that they joined the correct network.

Host cannot connect to own server. Use Direct Connect with your virtual IP, not 127.0.0.1. If that fails, try using the LAN tab.

VPN software shows no IP. Restart the VPN software. In ZeroTier, ensure your device is authorized in the web dashboard.

Frequently Asked Questions

Q: Is this method free? Yes, both Radmin VPN and ZeroTier are free for personal use, and the Arma 3 server files are free on Steam (you just need to own Arma 3).

Q: How many players can join? The limit depends on your internet upload speed and PC performance. With a typical home connection, 8-16 players is realistic. You can set maxPlayers in server.cfg.

Q: Do all players need to install the VPN? Yes, every player must have the same VPN software and be on the same virtual network to connect to your server.

Q: Can I use this method for modded servers? Yes, you can add mods to the server by placing them in the server folder and adding the -mod parameter. All players must also have the same mods installed and enabled.

Q: Will this work on a Mac? The Arma 3 server files are Windows-only. You would need to run a Windows virtual machine or use a Windows PC. The VPN software has Mac versions, but the server itself is not natively supported.

Q: What is the default port for Arma 3? The default is 2302. You can change it with the -port parameter, but then you must include the new port in the connection string.

Related

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