How to Set Up an Arma 3 Dedicated Server

Choose rent or self-host, then follow one fixed order

For a first server, the safest approach is to treat the job as a pipeline rather than a pile of settings. Most failed first launches come from doing everything at once: mods, custom missions, port guessing and config edits without a clean baseline.

1. Choose a rented panel or a self-hosted machine.
2. Install the dedicated server package with SteamCMD as app 233780 on a separate Steam account.
3. Keep the server in its own folder, separate from SteamCMD and separate from any local Arma 3 client.
4. Create a server config file and point -config at it.
5. Open UDP 2302 to 2306 and allow ping.
6. Pick one official mission for the first test.
7. Join from a client on the same branch, then use #login to become admin.

A rented panel usually handles the repetitive parts: SteamCMD updates, service start and stop, port assignment, and often a config editor. What it cannot skip is the logic of the server itself. You still need a mission, sensible passwords, the same branch on server and clients, and matching mods for every player who joins. If you want to compare panel-based options, the best Arma 3 server hosts page is the sensible place to start.

Self-hosting gives you full control, but it makes the network and operating system your problem. Official minimum hardware is a 2.4 GHz dual-core CPU, 2GB RAM and 32 GB HDD; recommended is a 3.5 GHz quad-core, 4GB RAM and a 32 GB SSD. Arma 3 server work is heavily concentrated on one or two threads, with one thread handling all AI, so faster core speed matters more than simply adding more cores. More cores help with the operating system, database tools or extras, but they do not fix a slow main simulation thread.

You also need a real IPv4 connection. Arma 3 dedicated does not support IPv6 or DS-Lite, so some home broadband lines are ruled out before you begin. If you only need a very small casual setup on the same PC, the Arma 3 Launcher can also host in server mode, but a separate dedicated install is far easier to repeat, update and troubleshoot.

Install on Windows with SteamCMD

SteamCMD needs a real Steam login, not an anonymous one. The usual recommendation is a separate Steam account with no purchases on it purely for the server, because SteamCMD caches the login on the machine and one account cannot be logged in from two places at once. That matters if the same account is also used to play the game on your client PC.

Keep these as separate folders: one for SteamCMD, one for the dedicated server, and one for any local Arma 3 client install. That separation stops file conflicts and makes updates cleaner. It also makes it obvious which folder you are backing up, launching and editing.

On the first run, Steam Guard normally sends a code by email. It is also normal for the script to need running more than once: one pass to authorise, one for SteamCMD to update itself, and another to actually download the server.

@echo off
cd /d C:\SteamCMD
steamcmd +login YOUR_SERVER_STEAM YOUR_PASSWORD +force_install_dir C:\Arma3Server +app_update 233780 validate +quit

Look at the flow below as the minimum working chain: install, point at config, open ports, then join and administer.

If the Arma 3 client is installed on the same machine, there is a known issue where the server can load the full client data instead of the dedicated package. The workaround is simple: start the server with an empty -mod= parameter. On the same machine, it is also wise to start the server before opening the Steam client, because Steam port conflicts can stop the client connecting back to the local server.

Install on Linux without running as root

On Linux, create a dedicated non-root user and run the server under that account. That keeps the server files and logs contained, avoids root-owned leftovers, and limits the damage if a tool or script behaves badly.

useradd -m -s /bin/bash steam
su - steam
mkdir steamcmd
cd steamcmd
# download steamcmd_linux.tar.gz into this folder first
tar -xvzf steamcmd_linux.tar.gz
./steamcmd.sh
# now at the Steam> prompt:
force_install_dir ./arma3/
login YOUR_SERVER_STEAM
app_update 233780 validate
exit
# back in the shell: create the profile folders
mkdir -p ~/.local/share/"Arma 3"
mkdir -p ~/.local/share/"Arma 3 - Other Profiles"

A 64-bit Linux install may still need the usual 32-bit libraries for SteamCMD. If SteamCMD will not start or download correctly, that is one of the first things to check.

Profile handling is the main Linux quirk here: -profiles= is broken, so the profile is created automatically at ~/.local/share/Arma 3 - Other Profiles/server/server.Arma3Profile. That means two things. First, do not waste time wondering why your chosen profile folder stays empty. Second, remember that difficulty and related profile settings live there, not beside your launch script.

cd ~/steamcmd/arma3
./arma3server_x64 -name=server -config=server.cfg

The process stays attached to the terminal, so it stops when your SSH session closes unless you launch it inside tmux or screen. To stop it cleanly, use Ctrl+C. If you add mods later, Linux expects -mod= paths to be relative and within or below the Arma 3 directory.

Know which files the server reads and creates

These are the files worth learning first. If you know what each one controls, you can usually tell within minutes whether a problem is config, mission, mod or launch-line related.

The important rule is this: server.cfg does not have a magic default name. You can call it almost anything, but the server only reads the file named in -config=. If you leave -config out, no server config is loaded at all, which is why so many new owners think the server is “ignoring” their settings.

Write a first server.cfg that only does the essentials

Your first config should do as little as possible while still proving the server works. That means name, join password if you want one, admin password, sane anti-cheat defaults, a player cap and one known mission.

hostname = "Example Co-op Server";
password = "examplejoin";
passwordAdmin = "exampleadmin";
maxPlayers = 16;
persistent = 1;
BattlEye = 1;
verifySignatures = 2;
kickDuplicate = 1;
logFile = "server_console.log";

class Missions
{
 class Mission1
 {
  template = "MP_CombatPatrol_01.Altis";
  difficulty = "Regular";
 };
};

• hostname is simply the browser name. If you omit it, the server falls back to the local machine name, which is usually less helpful.
• password controls who can join. Leave it empty for public access, or set one for a private group.
• passwordAdmin is the password you use in chat with #login. Joining the server is separate from becoming admin inside it.
• maxPlayers caps the server, but the real limit is the lower of this value and the mission’s slot count. If you set it higher than the mission supports, players still cannot exceed the mission slots. Headless clients also count as players.
• persistent = 1 keeps the mission running when everyone leaves. The mission keeps simulating with nobody on, which is the point: groups that drop in and out do not lose progress every time the last player leaves. It only works for missions that use base or instant respawn, a choice the mission maker makes in the mission itself.
• BattlEye = 1 and verifySignatures = 2 are the right day-one defaults. The trade-off is deliberate: a player with the wrong or unsigned content gets blocked at the door instead of joining a broken session, and cheaters have a much harder time.
• kickDuplicate = 1 stops duplicate identities connecting. That reduces confusion around ghosted sessions and duplicate admin presence.
• class Missions tells the server what it can run. The keyword class must be lowercase here, or you get a parsing error.
• template always takes the form missionName.terrainName. For a mission you upload, that is the .pbo name in MPMissions (for example MyMission.Altis.pbo becomes MyMission.Altis). Official missions that ship with the game use their class name instead and need no upload: MP_CombatPatrol_01.Altis is the COOP 12 Combat Patrol scenario, which makes a clean first test of the server and branch without anyone else’s scripting.

Use a launch line that leaves no doubt about what is loading

Readability matters. A good launch line tells you where the config is, where logs go, which profile name is in use and which port block the server owns.

"D:\Games\Arma3\A3Master\arma3server_x64.exe" "-profiles=D:\Games\Arma3\A3Master" -port=2302 -config=D:\Games\Arma3\A3Master\server.cfg -name=server -world=empty

-port=2302 sets the base port; the other Steam and BattlEye ports follow as offsets. -profiles= on Windows keeps logs and profile files in one predictable place. -config= is the critical switch that loads your server settings. -name=server picks the profile name, which decides where the .Arma3Profile is created.

-world=empty starts the server on an empty world, so it sits idle at the console until a mission is chosen instead of loading a terrain nobody is playing on. Players are not affected, because they always load into the mission’s own map.

Leave mods out until the vanilla server works. When you are ready, put client-and-server mods on -mod, server-only addons on -serverMod, and sort key files properly with the Arma 3 mods installation guide. On Linux, remember that mod paths must be relative and inside or below the Arma 3 folder tree.

Open the right ports and test the right network path

Arma 3 uses a small block of incoming UDP ports. Open them in the local firewall and, if the server is behind a router, forward them there as well. Opening only one side of that path is a common reason a server works on LAN but not for friends on the internet.

If BattlEye is enabled, the server also needs the related outgoing traffic on 2344 as TCP and UDP, and on 2345 as TCP. The server must also be pingable with ICMP echo reply. That is not a cosmetic detail: if the machine cannot answer ping, discovery and reachability checks can fail even when the UDP rules look right.

Avoid relying on upnp = 1 in server.cfg if you already control the firewall and router. On machines with active firewalls it can delay startup by 600 seconds, which looks like a hung server when it is really waiting on network automation you do not need.

Running more than one Arma 3 server on one machine is fine as long as you leave at least 100 ports between base values, such as 2302, 2402 and 2502, and give each server its own profile and config. That separation prevents log overlap, profile confusion and port collisions.

First launch, first join and first admin login

On first start you want two things: a console process that stays up, and an arma3.rpt log with no obvious config parse error. If the server opens and closes immediately, or the log shows mission or config syntax problems, fix that before worrying about the server browser.

Join from the in-game browser first, but if you do not see the server there, try direct connect. The browser can be wrong on the client side even when the server itself is available. Make sure the client branch matches the server branch: stable clients join stable servers, and development clients join development servers. For a first server, stable is the sensible choice.

Once connected, press / to open chat and enter #login followed by the admin password from passwordAdmin. Do not forget the #. After that, choose the mission from the mission list. If you already set a one-mission rotation, the server can also auto-select once someone is connected, but logging in and choosing it yourself proves that admin works properly.

If you want trusted people to log in without sharing the admin password, add their SteamID64 values to the config like this:

admins[] = { "STEAMID64_HERE" };

Only one logged-in admin can exist at a time without BattlEye RCon, so keep admin access intentional rather than casual. Once the server stays up, loads an official mission, and lets multiple friends join and rejoin cleanly, you have a working baseline. Only then is it worth adding user-made missions, large mod sets, headless clients or detailed bandwidth tuning in Arma3.cfg.

For updates, stop the server and run app_update 233780 validate again whenever Arma 3 is patched. Version mismatches are one of the most common reasons a server that worked yesterday suddenly refuses clients today.

When something goes wrong, check in this order

This flow is the fastest way to narrow first-day problems without changing ten things at once.

First-launch checklist

Once every row above is true, you have a real baseline. The next steps are usually mods, signature keys, server-only addons, more detailed admin permissions, headless clients for AI-heavy missions, and careful bandwidth tuning in Arma3.cfg. Do those one at a time so you always know what changed.

Arma 3 dedicated server FAQ

Do I need to own Arma 3 to run a dedicated server?

No. The dedicated server package is free and is installed through SteamCMD as app 233780. You still need a real Steam account to log in with SteamCMD, but that account does not need an Arma 3 purchase on it.

What ports does an Arma 3 dedicated server use?

The normal incoming block is UDP 2302 to 2306: game traffic, Steam query, Steam service traffic, a reserved VON offset and BattlEye. If BattlEye is enabled, related outgoing traffic also uses 2344 as TCP and UDP, plus 2345 as TCP. The server should also answer ICMP echo reply so it can be pinged.

Why is my server not loading my server.cfg?

Because Arma 3 does not load a default server config by file name alone. The file can be called almost anything, but your launch line must point to it with -config=. If that path is wrong, or missing, the server starts with no server config loaded.

Why can’t my friends see my Arma 3 server?

The usual causes are missing UDP forwarding, a local firewall rule, no real IPv4 on the internet connection, or simply the in-game browser misbehaving. Test direct connect before assuming the server is down, then verify the UDP block and ping response. If only local clients can connect, the problem is nearly always on the network edge rather than in the mission file.

How do I become admin on my Arma 3 server?

Join the server first, open chat with /, and type #login followed by the value from passwordAdmin. If you prefer not to share that password, you can list trusted SteamID64 values in admins[] so those users can log in directly. Without BattlEye RCon, only one logged-in admin can be active at a time.

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