A start-to-finish guide for hosting your own Astroneer dedicated server — install the free Steam tool (App ID 728470), set Port=8777, edit AstroServerSettings.ini, forward the port, then claim ownership in-game. Windows-only, up to 8 players, current for Astroneer 1.40 — including the platform gotcha and the "starts then closes" error everyone hits.
A dedicated server runs the world independently of any player, so it needs a machine that stays on. Astroneer is light compared with most survival games, so the bar is low — but the OS requirement is strict.
728470) is a separate, free app from the Astroneer game (361420).MaximumPlayerCount).Astroneer's server is a first-party, free download from Valve's servers — no second copy of the game, no third-party tooling needed to stand it up. The gameplay-relevant settings live in a single editable file (AstroServerSettings.ini), which is why this is a setup guide with a config reference rather than a slider-based generator.
Seven steps from nothing to a claimed, running server. Steps 1–3 install and generate config; 4–5 configure it; 6–7 launch, claim, and keep it alive.
In the Steam client, the ASTRONEER Dedicated Server shows up under Library → Tools (turn on the "Tools" filter). Install it there. It's free and a separate app from the game client (361420) — you don't need to own or install the game on this machine.
Running headless or on a box without the Steam GUI? Use SteamCMD with anonymous login:
steamcmd +login anonymous +force_install_dir C:\Astroneer +app_update 728470 validate +quitThe validate flag verifies the files — keep it; it's also how you repair a broken install later.
Launch AstroServer.exe once. On first run it generates two config files in:
...\Astro\Saved\Config\WindowsServer\
├─ Engine.ini
└─ AstroServerSettings.iniYour worlds are saved to ...\Astro\Saved\SaveGames\. Once the files exist, stop the server before editing them — see the warning below.
AstroServerSettings.ini on shutdown, so any change you make while it's running gets overwritten and lost. Stop the server, edit, save, then start it again.Engine.iniEngine.ini is generated blank. Add a [URL] section with Astroneer's default UDP port, 8777:
[URL]
Port=8777Optional but recommended on busier servers — raising the network rate caps reduces rubber-banding:
[/Script/OnlineSubsystemUtils.IpNetDriver]
MaxClientRate=1000000
MaxInternetClientRate=1000000AstroServerSettings.iniOpen AstroServerSettings.ini (under [/Script/Astro.AstroServerSettings]) and set these five to get online — the full key list is below:
ServerName — the name shown in the in-game server browser.OwnerName — your exact Steam display name. This is what grants you ownership (see Ownership).ServerPassword — the join password; leave empty for an open server.MaximumPlayerCount — max players, up to 8.PublicIP — your WAN/public IP with no port (or leave blank to auto-detect).PublicIP is the #1 trap. It must be your bare public IP — 203.0.113.10, not 203.0.113.10:8777. A wrong value or an appended port makes the server boot and then immediately close.On a home connection, forward the port so anyone outside your network can connect:
...\Astro\Binaries\Win64\AstroServer-Win64-Shipping.exe.Full detail and the CGNAT caveat are in the port section below.
Start AstroServer.exe. In Astroneer, open Co-op → Join (Dedicated Server), add the server's IP:port, and connect.
The first player whose name matches OwnerName becomes the owner — the server then writes their SteamID64 into OwnerGuid automatically. That gives you the in-game admin menu: kick, ban, whitelist, force-save, and a graceful shutdown. Full detail in Ownership & Admin.
Stay alive: wrap AstroServer.exe in a Task Scheduler task (run at startup, restart on failure) or register it as a service with NSSM, so it survives crashes and reboots.
+app_update 728470 validate (or reinstall via the Steam Tools entry) and restart — otherwise clients on the new version can't join. Your saves carry over across updates.EnableAutoRestart in the config; it isn't a real key.Astroneer uses a single UDP port. The connection problems almost always come down to this port, the firewall, or your IP — not the game.
| Port | Protocol | Purpose | Forward? |
|---|---|---|---|
| 8777 | UDP | All game traffic. Set with Port=8777 in Engine.ini; forward it to the server's LAN IP. | Yes |
Add the Windows Firewall inbound rule against the actual server binary, AstroServer-Win64-Shipping.exe (in ...\Astro\Binaries\Win64\), so Windows allows the traffic through. And remember: PublicIP in the settings file is your public IP only — never with :8777 on the end.
These are the verified keys under [/Script/Astro.AstroServerSettings], with their defaults. Edit them only while the server is stopped — it rewrites this file on shutdown.
| Key | What it does | Default | Note |
|---|---|---|---|
| ServerName | Display name in the in-game server browser. | Astroneer Dedicated Server | — |
| OwnerName | Grants ownership to the player with this exact Steam display name. | (empty) | Required for admin. See Ownership. |
| OwnerGuid | The owner's SteamID64. | 0 | Leave 0 — auto-fills on first owner connect. |
| ServerPassword | Password required to join. | (empty) | Empty = open server. |
| MaximumPlayerCount | Max simultaneous players. | 8 | Ceiling is 8. The real key — not MaxConnections. |
| PublicIP | Your public/WAN IP. | (auto) | No port. Wrong value = starts then closes. |
| MaxServerFramerate | Tick cap while players are active. | 30 | Higher = smoother + heavier. |
| MaxServerIdleFramerate | Tick cap while the server is empty. | 3 | Low value saves CPU when nobody's on. |
| AutoSaveGameInterval | Seconds between autosaves. | 900 | 900s = every 15 minutes. |
| BackupSaveGamesInterval | Seconds between save backups. | 7200 | 7200s = every 2 hours. |
| ActiveSaveFileDescriptiveName | Which save file the server loads. | SAVE_1 | — |
| bLoadAutoSave | Load the most recent autosave on boot. | True | — |
| PlayerActivityTimeout | Idle-kick timer, in seconds. | 0 | 0 = never kick for idling. |
| DenyUnlistedPlayers | Whitelist switch. | False | True = whitelist-only; manage the list in the in-game admin panel. |
| ConsolePort / ConsolePassword | Remote-console (RCON-style) interface. | 1234 / auto | Advanced; a random password is generated. |
| bWaitForPlayersBeforeShutdown | Hold shutdown until players leave. | False | Advanced — usually left alone. |
| bDisableServerTravel | Block server-travel behaviour. | False | Advanced — usually left alone. |
| ServerGuid / HeartbeatInterval / ServerAdvertisedName | Internal / advertised-listing internals. | (auto) | Leave at defaults. |
MaxConnections, MaxServerIdleTimeout and EnableAutoRestart are not real Astroneer settings. Max players is MaximumPlayerCount; there's no idle-timeout-shutdown key; and auto-restart is handled by an external wrapper (Task Scheduler / NSSM / AstroLauncher), not the config file.Astroneer doesn't use a console-command admin login. Ownership is claimed by name match, and it's the most-missed step.
Set OwnerName to your exact Steam display name — the name your friends see on Steam, not your in-game character name. Leave OwnerGuid=0. The first player who connects with that exact name is made the owner, and the server writes their SteamID64 into OwnerGuid so the claim sticks. (If you leave both OwnerName and OwnerGuid blank, the first person to connect — anyone — becomes owner, so don't leave it open on a public server.)
As owner you get the in-game admin menu, which can:
DenyUnlistedPlayers=True, restrict the server to an approved list managed from the panel.OwnerName doesn't exactly match your Steam name (a space, capital letter, or recent name change). Fix the name in the file (server stopped), restart, and reconnect.Almost every "my Astroneer server won't work" post is one of these. Find the symptom, apply the fix.
| Symptom | Cause & fix |
|---|---|
| Server starts then immediately closes | The classic. PublicIP in AstroServerSettings.ini is wrong or has a :port on it. Set it to your bare public IP (no port), or leave it blank to auto-detect, and restart. |
| Nobody can see or connect to the server | Forward UDP 8777 to the server's LAN IP, add the firewall rule for AstroServer-Win64-Shipping.exe, confirm you're advertising your real WAN IP, and rule out CGNAT (if your router's WAN IP ≠ your public IP, you're behind it). |
| You can't join over your own LAN | Connect using the external/public IP, not the LAN IP — many routers don't support NAT loopback (hairpinning). |
| You're not getting owner / admin powers | OwnerName must match your Steam display name exactly (not your character name). Fix it with the server stopped, restart, reconnect. |
| Some friends randomly fail to join | Players must disable any DLC to connect to a dedicated server. Have them turn off DLC and retry. |
| Clients rejected after a game update | The server didn't update itself. Re-run +app_update 728470 validate (or reinstall the Steam Tools entry) and restart — saves persist. |
| Xbox / Microsoft Store / Switch player can't join | Not a bug. Self-hosted servers are Steam / Epic / PS4 only. Those platforms need an official partner-hosted server. |
728470) using anonymous login — you don't need a second copy of the game to host it. The only cost is optional: renting a machine to run it on.MaximumPlayerCount in AstroServerSettings.ini, and 8 is the ceiling. The real key is MaximumPlayerCount — MaxConnections is not a valid Astroneer setting.Port=8777 under a [URL] section in Engine.ini, then forward UDP 8777 to the server's LAN IP and add a matching Windows Firewall rule. See the port section.PublicIP value. It must be your bare WAN/public IP with no port — if it's wrong, or you appended :8777, the server boots and then closes. Set your real public IP, or leave it blank to auto-detect. See troubleshooting.+app_update 728470 validate (or reinstall via Steam Tools) and restart, or clients on the new version can't join. Saves persist across updates. There's no auto-update or auto-restart config key — scheduled restarts come from a wrapper like Task Scheduler or AstroLauncher.728470) is a standalone app, separate from the Astroneer game (361420). You don't need to own or install the game on the box that runs the server.Hosting another game too? Our config generators turn server settings into sliders and toggles and hand you a ready-to-paste file — no hand-editing.