How to set up an Arma 3 server from scratch

What you need first

• An active Arma 3 plan on Fatality Servers — see our Arma 3 hosting plans.
• A Steam copy of Arma 3 on each player's PC (required for clients).
• A Steam account for SteamCMD Workshop downloads — login via the panel's SteamCMD prompt.
• RAM: 4 GB for vanilla 30-slot, 8 GB for medium-size modsets (ACE + CBA + RHS), 16 GB+ for heavy milsim or Exile servers with lots of persistence.
• Decent CPU. Arma 3's server is single-thread-bound, like most Arma games. High clock speed on one core matters far more than core count.

Deploy the server (1-click)

Our Arma 3 template runs SteamCMD to install the arma3server binary (App ID 233780), sets up the base directory structure, and ships a working default server.cfg.

1. Pick the Arma 3 template at checkout

   On our Arma 3 hosting page, pick a plan sized for your slot count and mod load. Arma 3 is a bandwidth-hungry game — all Fatality plans ship unmetered 1 Gbps, but pick a location near your players since latency drives hit-reg quality.

2. Wait for SteamCMD to download the server

   Server files are ~15 GB. First install takes 4-8 minutes. Console shows Success! App '233780' fully installed. when ready.

3. First boot (no mods)

   Start the server with a vanilla mission to verify it runs. Console shows Host identity created. and then Server started on port 2302 when listening.

Configure server.cfg

The main config file. Located at:

arma3server/cfg/server.cfg

A working default you can paste and tweak:

// Identity
hostname = "[EU] My Arma 3 Server — Antistasi, modded";
password = "";                      // Blank = no join password
passwordAdmin = "change-me-strong"; // Admin login password (/#login)
serverCommandPassword = "";         // For scripted commands

// Player behaviour
maxPlayers = 40;
persistent = 1;                     // World persists across mission restarts
kickDuplicate = 1;                  // Kick duplicate GUIDs
verifySignatures = 2;               // Mod signature validation (2 = strict; 0 = off)
disconnectTimeout = 30;             // Seconds before disconnect

// Server info
motd[] = {
  "Welcome to the server!",
  "Teamkilling = permaban.",
  "Discord: discord.gg/yourlink"
};
motdInterval = 5;

// Mission selection
class Missions {
  class Mission01 {
    template = "Antistasi.Altis";    // Mission file name (minus .pbo)
    difficulty = "Regular";
  };
};

// Voting
voteMissionPlayers = 3;              // Players needed for a mission vote
voteThreshold = 0.5;                 // 50% vote majority

// File patching — only enable if you know why
allowedFilePatching = 1;             // 0 = none, 1 = HC only, 2 = all clients

// Logging
logFile = "server.log";
timeStampFormat = "short";

// BattlEye
BattlEye = 1;                        // Enable BE anti-cheat

// Headless client support (see section below)
headlessClients[] = {"127.0.0.1"};
localClient[] = {"127.0.0.1"};

The knobs that matter most for daily ops:

• hostname — shown in the server browser. Include region + mission + "modded" tag so players can filter.
• passwordAdmin — lets you #login <pass> in-game to get admin access. Keep strong.
• verifySignatures = 2 — the strict setting rejects any mod without a matching .bikey in the server's keys/ folder. Essential for public servers; turn off only for debugging.
• persistent = 1 — enables the server to keep running between missions. Required for Exile, Antistasi, and any persistence-based gamemode.
• allowedFilePatching — keep at 0 or 1 for public servers. Setting to 2 lets any client inject arbitrary SQF into the server and is effectively a cheater's invitation.

Tune basic.cfg (networking)

basic.cfg holds network tuning. Location: arma3server/cfg/basic.cfg. Defaults work for small servers; bigger servers with mods need tuning:

// Bandwidth targets
MinBandwidth = 4194304;          // 4 Mbps minimum guaranteed per client
MaxBandwidth = 104857600;        // 100 Mbps max per client (raise for high slot counts)
MinErrorToSend = 0.001;          // Smaller value = more accurate client sync
MinErrorToSendNear = 0.01;

// Packet sizes
MaxMsgSend = 384;                 // Messages per frame (raise carefully)
MaxSizeGuaranteed = 512;
MaxSizeNonguaranteed = 256;

// Ticks
MaxCustomFileSize = 1310720;      // Custom file limit (face textures, etc.)

class sockets {
  maxPacketSize = 1400;
};

Bigger servers (40+ slots) with heavy scripts benefit from raising MaxMsgSend to 512-1024 and MaxBandwidth to 524288000 (500 Mbps). Too high breaks things — start conservative, raise if you see "desync" warnings.

Mission files and rotations

Missions live as .pbo files in:

arma3server/mpmissions/

Upload mission .pbos via SFTP, then reference them in server.cfg's Missions class using the file name minus the .pbo extension and minus the map suffix.

Example: the file Antistasi.Altis.pbo is referenced as:

template = "Antistasi.Altis";

Rotating multiple missions

Add more classes inside Missions:

class Missions {
  class Mission01 {
    template = "Antistasi.Altis";
    difficulty = "Regular";
  };
  class Mission02 {
    template = "Liberation.Malden";
    difficulty = "Regular";
  };
};

When mission ends, server loads the next in the list. #missions and #reassign from admin chat let you jump between them manually.

Loading mods — the -mod parameter

Arma 3 loads mods via startup command-line parameters, not a config file. The panel's Settings → Startup Parameters field is where you wire them up.

Basic mod loading

-mod="@CBA_A3;@ace;@RHSUSAF;@RHSAFRF" \
-serverMod="@EnhancedMovement_Server" \
-config=cfg/server.cfg \
-cfg=cfg/basic.cfg \
-port=2302 \
-name=server

Notes:

• Mod folders are prefixed @ and separated by semicolons inside quotes
• -serverMod is for server-side-only mods (not loaded on clients) — signature verification ignores these
• Order matters for some dependencies — CBA_A3 usually goes first
• -port=2302 is the default (game port). Our panel opens 2302-2306 UDP by default

Where mods live

Mod folders go directly in the server root:

arma3server/@CBA_A3/
arma3server/@ace/
arma3server/@RHSUSAF/
arma3server/keys/
  ├── cba_a3.bikey
  ├── ace.bikey
  ├── rhsusaf.bikey

The .bikey signature keys for each mod go in keys/. If a mod ships a .bikey, put it there or clients will fail signature verification.

Workshop mods via SteamCMD

Most mods live on the Steam Workshop. Two download paths:

Via SteamCMD (preferred)

From the panel's SteamCMD prompt (or via the file manager's terminal add-on):

login <your-steam-username>
# (enter password + Steam Guard if prompted)
workshop_download_item 107410 <workshop-id>
quit

Mods land in Steam/steamapps/workshop/content/107410/<id>/. Move them to your Arma 3 server root as @ModName/, and copy any .bikey files from the mod's keys/ subfolder into your server's top-level keys/.

Shared community modpacks

Big communities often distribute a modpack as a single download or via Arma 3 Sync. This is the norm for milsim groups — everyone runs exactly the same mod set, guaranteed by the community's distribution method.

Exile, Altis Life, Antistasi

Exile Mod (survival)

Persistent-world DayZ-style survival on Arma 3. Requires:

• The Exile server files (get from exilemod.com)
• MariaDB / MySQL for persistence (our panel provides one)
• Extension DLLs for DB access (extDB3, included with Exile)
• The Exile client mod loaded on every player's launcher

Setup is non-trivial — budget a weekend. The Exile wiki has a line-by-line installer walkthrough. The DB schema is Exile_MySQL.sql; import it via phpMyAdmin in the panel.

Altis Life (roleplay)

Framework for cops/robbers/medic RP on Altis. Community is smaller than it was pre-FiveM but still alive. Setup pattern is similar to Exile — MySQL for persistence, extension DLLs, framework-specific mission .pbo.

Antistasi (guerrilla warfare)

Most approachable of the three — runs as a plain mission .pbo, no extra mods or database required. Persistent faction war where 3-10 players fight a dynamic enemy across Altis, Malden, Tanoa, or any modded map. Drop the .pbo in mpmissions/, set it as the active mission, start the server. Done.

Headless clients for AI offloading

Arma 3's server has a hard limit: it simulates AI on a single CPU thread. On a 40-slot milsim server with 200 AI, the server tick drops to 10 FPS and gameplay feels like treacle.

The fix: a headless client (HC) — a second Arma 3 process that connects like a player, takes no slot, but runs AI locally. The mission script (if it supports HC) offloads AI groups to it. Result: server tick stays at 40+ FPS even with heavy AI loads.

1. Add HC IPs to server.cfg

   If running HC on the same box (common):

   headlessClients[] = {"127.0.0.1"};
   localClient[] = {"127.0.0.1"};

   For remote HC on another server, list its IP instead.

2. Start the HC process

   A second arma3server binary with these flags:

   ./arma3server \
     -client \
     -connect=127.0.0.1 \
     -port=2302 \
     -password=<your-server-password-if-set> \
     -mod="same-mod-list-as-server" \
     -name=HC_01

3. Verify via admin chat

   After both are running, #login <admin-pass> in-game, then #players — you should see HC_01 listed as a player (it's a client from the server's perspective). Mission script handles the offloading logic.

BattlEye anti-cheat

BattlEye is Arma 3's anti-cheat. Recommended on: leave it on for any public server.

// In server.cfg
BattlEye = 1;

BE config lives in arma3server/battleye/BEServer_x64.cfg. Typical content:

RConPassword = your-rcon-password
RConPort = 2302
MaxPing = 300
RestrictRCon = 1

BattlEye filters (optional, advanced)

For heavily modded servers, BE occasionally false-flags legitimate mod actions. The community maintains curated scripts.txt, createvehicle.txt, etc. filter files at github.com/AridGroup/A3_BE_Filters. Drop these into battleye/ to reduce false-positive kicks.

Connect and test

1. Launch Arma 3 with matching mods

   Start Arma 3 via the launcher, enable the same mod set as your server. Load order should match where possible.

2. Join via the Multiplayer browser

   Multiplayer → Server Browser. Filter by name. Double-click to join. Or Direct Connect → enter YOUR-IP:2302.

3. Log in as admin

   Chat input: #login your-admin-password. You're now admin — #missions, #kick, #ban, #shutdown all work.

Common errors and fixes

"Bad CD Key" / "Session lost"

Arma 3 anti-piracy kicked the client. Usually a legitimate client glitch — have the player verify files via Steam and retry. If persistent, the player's Steam / BE state is desynced; a full game reinstall fixes it.

"Signature check failed" on join

verifySignatures = 2 is rejecting the player's mod set. Either:

• The mod's .bikey isn't in the server's keys/ folder — copy it
• The player is running a different build than the server — sync mod versions
• A mod has been re-signed and old keys don't match — re-download keys

Server shows in browser but won't connect

• BattlEye isn't loaded on either side — restart both server and client with BE explicitly on
• The server's ports (2302-2306 UDP) are blocked — our panel handles this, but a custom firewall might not
• Version mismatch — update the client via Steam or pin the server to the older version via SteamCMD's app_update 233780 -beta <branch>

Server tick drops under AI load

Classic "server FPS dies when 200 AI spawn". Fix: add a headless client (see Headless clients). If you can't, the next-best options are reducing AI count in the mission, turning off some AI behaviour modules (ACEX AI), or upgrading to a higher-clock CPU.

Workshop mod downloaded but won't load

Check:

• Folder is named with a leading @ (e.g. @CBA_A3)
• Folder is in the server root, not in a workshop/ subdirectory
• .bikey file from the mod is in keys/
• -mod parameter in the startup command lists the mod

Exile / Altis Life DB connection errors

Check your extDB3-conf.ini MySQL connection string — host, user, password, database name. MariaDB 10.x and MySQL 8.x both work with the latest extDB3; if you're on an older Exile build, you may need to match extDB2. Exile wiki has a compatibility table.

Admin commands don't work after #login

The admin password in server.cfg is set but the server never reloaded. Full server restart applies the config change. #login with an old password silently fails.

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Stuck on something specific? Email support with your server IP, mod list, and the last 50 lines of your Arma 3 server console — we'll usually have an answer within the hour.