How to Set Up an Icarus Dedicated Server

Short answer: an Icarus dedicated server is a separate Steam application, app ID 2089300, that installs anonymously without an Icarus licence and runs one prospect at a time. It is not the game client in server mode, and RocketWerkz recommend it specifically for Open World play.

This page covers what the server actually is, what it needs, and the handful of settings that decide whether your first boot works.

Checked against Icarus 3.0.27.157242-rel-DangerousHorizons

That is the Week 249 build, released 10 September 2026. RocketWerkz ship a changelog every Thursday, so version numbers here move weekly — the server structure below has been stable for far longer.

What you are actually installing

Icarus multiplayer works two ways, and they are not the same product:

RocketWerkz are direct about which to pick. The Icarus Steam store page says: "Go at it alone, invite up to 8 Steam friends to join your game or play on dedicated servers. Dedicated servers are free to run and are recommended for Open World sessions."

The reason is structural rather than performance-related. In a peer-to-peer session the prospect file sits on the host's hard drive, so nobody else can continue it — and Open World is the mode people expect to play for months. A dedicated server takes that file off any one player's machine.

Installing it

The server ships as its own Steam app. From RocketWerkz's setup guide:

"Installing via SteamCMD allows installing Icarus Dedicated Server without needing an Icarus license."

On a bare machine, that is four SteamCMD steps:

force_install_dir C:\IcarusServer
login anonymous
app_update 2089300 validate
quit

Note the app ID. 1149460 is the game; 2089300 is the server. Pointing SteamCMD at the game ID downloads something you cannot run headless.

There is no Linux build. The dedicated server is a Windows binary — IcarusServer-Win64-Shipping.exe — which is why Linux hosts run it under Wine rather than natively.

On a hosted Icarus server

If you are running a hosted Icarus server, the SteamCMD stage is already done. Our deployment pulls app 2089300 with the Windows platform flag set, runs it under Wine, and pre-places RocketWerkz's own ServerSettings.ini template so you are not staring at an empty config directory on first boot.

Three variables are yours to edit:

Everything else — the Wine architecture, the app ID, the Windows install flag — is fixed, because changing any of it produces a server that does not start.

Leave AUTO_UPDATE on

Icarus patches every week, and the in-game server browser now filters to matching versions by default. RocketWerkz made that change in the Week 244 update of 6 August 2026, when the server browser came out of beta. A server one patch behind is not "empty" — it is invisible to almost everyone browsing.

The name field is worth a second look. RocketWerkz's -SteamServerName launch parameter accepts up to 64 characters, but the panel validates SERVER_NAME at 32. Write a name that survives the shorter limit.

Ports

RocketWerkz document two ports, and the defaults are widely quoted:

• Game port — default 17777
• Query port — default 27015, what Steam server-list features use

Both are set at launch with -PORT= and -QueryPort=. On a hosted server you do not get those defaults and you do not need to forward anything; your panel assigns the ports and shows them on the server page. Self-hosting at home is where port forwarding becomes your problem.

First boot, and the file that does not exist yet

This trips up nearly everyone. Quoting RocketWerkz's setup guide directly:

"As of current the settings file gets generated on first prospect/lobby, we are working on including this file as part of the install"

So the sequence is: start the server once, let it reach the lobby, then edit the config. RocketWerkz document the path the server reads as:

[ServerInstallDirectory]\Icarus\Saved\Config\WindowsServer\ServerSettings.ini

On a hosted server everything lives under /home/container, so that is /home/container/Icarus/Saved/Config/WindowsServer/ServerSettings.ini.

You may find two copies. Our installer drops RocketWerkz's template one level up, in Icarus/Saved/Config/, so the directory is never empty on a fresh deployment; the server generates and reads its own copy in the WindowsServer subfolder. Edit the one in WindowsServer — that is the file the server loads.

Two other paths under the same Saved folder matter later:

That second one is how you move a world you already started at home onto a server — the .json file drops straight into it. RocketWerkz's warning on that is emphatic and worth repeating: do not rename the file or edit the JSON. Their migration guide says changing either "will corrupt your saved data" and that the result is unrecoverable.

The settings to change before anyone joins

Only a few of the config options matter on day one. The full list is covered in Icarus Server Settings Explained, but two are security-relevant:

• AdminPassword — ships empty. RocketWerkz note that if it is left empty, "just using the RCON /AdminLogin will give admin privilege's to a player (effectively an empty password)". Anyone who joins can then kick, ban and dump the server back to lobby.
• JoinPassword — ships empty too. Set it if the server is private.

Once it is set, admin is claimed in chat with /AdminLogin. The full command set is short and unusual, and it is documented in Icarus Console Commands: What Actually Works — read it before you expect an RCON tool to connect, because Icarus has no RCON listener despite the naming.

Common Questions

Do I need to own Icarus to run the server?

No. The server installs through SteamCMD under login anonymous. You need a licence to play, not to host.

Is there a Linux version of the Icarus server?

No. RocketWerkz ship a Windows binary only. Linux hosts run it through Wine, which works but means the config directory is still named WindowsServer.

Why is my server not in the server browser?

The most common cause since Week 244 is version mismatch — the browser filters to matching versions by default, so a server that missed this week's patch simply will not appear for most players. Update it, then check the query port.

How many prospects can one server run?

One. A server runs a single prospect — mission, Open World or Outpost — at a time, and switching between them means returning to the lobby. This is covered in Icarus Prospects on a Dedicated Server.

Where is ServerSettings.ini?

It does not exist until the server has started once and reached a lobby or prospect. Boot it, stop it, then look in Icarus/Saved/Config/WindowsServer/.

Can I move my single-player world to the server?

Yes. Copy the prospect .json from %LocalAppData%\Icarus\Saved\PlayerData\<SteamID>\Prospects\ into the server's Icarus/Saved/PlayerData/DedicatedServer/Prospects/ folder, without renaming it.

What to Read Next

• Icarus Console Commands: What Actually Works — the seven admin commands, and why there is no console key
• Icarus Prospects on a Dedicated Server — how one server runs one world
• Icarus Server Settings Explained — every option in ServerSettings.ini
• How to Play Icarus With Friends — joining, player limits and the server browser

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