Barotrauma dedicated server and mods

A Barotrauma dedicated server is a free download (Steam app 1026340, anonymous login) with Linux and Windows builds - DedicatedServer and DedicatedServer.exe. Its settings live in serversettings.xml in the server folder; permissions in Data/clientpermissions.xml; the enabled mods in config_player.xml. By default it listens on UDP 27015 for the game and UDP 27016 for the Steam query. It is light - 1-2 GB of memory and one or two cores carry a full sixteen-player crew - so what decides whether a Barotrauma server works is configuration: who gets which permissions, which mods everyone has, and how the campaign is saved.

How Barotrauma servers work#

Barotrauma is a round-based game. A crew boards a submarine, completes a mission (or a campaign leg), and the round ends in the lobby. A dedicated server is a lobby that is always available, with no player carrying the host role, which changes three things compared with hosting from the game:

• Nobody's PC is the server. Hosting from the game runs a server process alongside the host's client, and the host's connection carries everyone.
• The lobby has no owner by default. On a dedicated server, someone has to be given the permissions to start rounds, change submarines and kick players - otherwise the server either does nothing or uses its auto-start settings.
• Campaigns persist on the server. A multiplayer campaign is saved by the server, so the crew can continue with whoever shows up.

The game modes are Sandbox, Mission (one-off rounds), Multiplayer Campaign (persistent progress, money, and a submarine you upgrade over time) and PvP. Traitors, the karma system and voting for submarines and modes are all server settings, and they shape the community more than any hardware choice.

Choosing the kind of server you run

Before touching a setting, decide what the server is for, because the right values for a crew of friends and for a public server are almost opposite.

A private campaign crew - four to eight people who know each other - wants a password, the campaign mode, traitors off, karma off or lenient, and one or two people with full permissions. Rounds start when the crew is ready. The submarine is chosen together and upgraded over weeks. The server can sit in the lobby with nobody on it for days without anything going wrong, and the campaign picks up where it left off.

A public mission server wants the opposite. Rounds should start on their own, because nobody can be relied on to press Start. Submarine and mode voting gives strangers a say without giving them power. Karma should be on, because welded doors, flooded reactors and friendly fire are the everyday griefing on public Barotrauma servers, and karma handles most of it before a moderator notices. Traitors are a matter of taste: they are part of what makes Barotrauma memorable, and they are also the setting that drives new players away fastest. Many public servers run traitors on a named schedule or on a separate server, so players know what they are walking into.

A public campaign is the hardest to run well. Progress belongs to whoever happens to be online, money can be spent by people who leave the next day, and one bad round can sink the submarine the regulars spent weeks upgrading. It works best with a whitelist-style community - a password shared on Discord - rather than an open listing.

Put the choice in the server name. "Campaign, no traitors, EU" tells a player in two seconds whether to join, and saves you a lobby full of people expecting something else.

Requirements and resource usage#

Barotrauma's server is one of the lightest you will run. Physics, AI for creatures and NPCs, and networking are the cost; the world is one level per round, generated fresh.

• CPU: one fast core carries the simulation. Large submarines with many devices and wiring, and levels full of creatures, cost the most.
• Disk: the server installs to a few gigabytes; mods and submarines add to it.
• Network: modest, but latency affects how combat and repairs feel. Latency, jitter and packet loss covers what to measure.

The sixteen-player figure is the usual maximum crew. Larger values exist in mods and some settings, but the game's submarines and missions are designed around crews up to that size.

Installing and first start#

On Linux:

$ steamcmd +force_install_dir /home/barotrauma/server +login anonymous +app_update 1026340 validate +quit$ cd /home/barotrauma/server$ ./DedicatedServer

On Windows run DedicatedServer.exe. SteamCMD explained covers keeping the install updated, which matters here: Barotrauma servers must match the client version exactly.

The first start writes serversettings.xml with defaults and opens the lobby. Stop it cleanly (the panel's stop, or the console's own exit command - help lists it), edit the settings, and start it again. The server writes its settings back when they change through the game, so edit with the server stopped.

serversettings.xml#

The file is a single serversettings element with its settings as attributes. A trimmed example of the parts you will edit:

<serversettings  name="Europa Salvage Co."  public="true"  port="27015"  queryport="27016"  maxplayers="12"  password=""  enableupnp="false"  autorestart="false"  startwhenclientsready="false"  allowspectating="true"  karmaenabled="true" />

What the important ones do:

The file holds many more attributes - traitor settings, voting rules, submarine selection mode, allowed and banned items, respawn behaviour and more - and the set grows with updates. Most of them are easier to change in the game, through the server settings screen, by a player with the right permissions; the server then writes them to the file. Edit the file directly for the network settings and anything you want fixed before the first player joins.

Ports and connecting#

Both must be open and both are UDP. If your host gives you different numbers, set port and queryport to match. Game server ports explained covers why a server can be in the list but refuse connections, or the other way round.

Players find a public server in the in-game server list. A private server can be joined by address and port through the direct join option. If the list shows the server but joining times out, the game port is the problem; if direct join works but the server is not listed, the query port is.

Permissions, ranks and console commands#

Barotrauma has a proper permission system, which is good, because a dedicated server with no permissions given out has nobody who can run it.

Permissions are granted per client and stored in Data/clientpermissions.xml. Rank presets - such as Moderator and Admin - bundle permissions and live in Data/permissionpresets.xml. Individual permissions include managing rounds, selecting submarines and modes, kicking, banning, managing settings and using console commands, and the console command permission can be restricted to a list of specific commands.

The simplest way to set up the first admin is from the server console:

giverank PlayerName admin

After that, admins can manage others in the game from the player list: right-click a player, give a rank or individual permissions, and the server saves them.

Commands typed in the server console (or in game by a player with console permissions):

The command set is large and changes between versions; help is the reference for your build. Bans are saved in the server's data so they survive restarts.

For a public server, think about permissions in layers: everyone can vote, trusted regulars can start rounds and pick submarines, moderators can kick, and very few people can ban or change settings. Server rules, moderation and staff has more on that structure, and the karma system handles the common griefing - welding doors shut, shooting crew - without an admin present.

Mods and content packages#

Barotrauma mods are content packages: folders with a filelist.xml describing what they contain. On a dedicated server:

1. Download the mod - on a client, subscribe in the Steam Workshop and copy the downloaded folder, or take it from the author.
2. Put the folder in the server's LocalMods directory.
3. Enable it in config_player.xml, where the server keeps its list of enabled packages.
4. Start the server and watch the log for content errors.

The enabled list looks like this:

<contentpackages>  <corepackage path="Content/ContentPackages/Vanilla.xml" />  <regularpackages>    <package path="LocalMods/ExampleMod/filelist.xml" />  </regularpackages></contentpackages>

The folder name is a placeholder; use the mod's own folder. Order matters - packages later in the list override earlier ones when they change the same thing - so put large overhauls first and small patches after them.

When players join, the game compares their content with the server's and offers to download what is missing, from the Workshop or from the server directly. That makes Barotrauma one of the easier games for modded multiplayer, but it still means a download standing between a new player and their first round. Keep the list lean on public servers.

Rules that save a modded server:

• Update mods together with the game. A game update can break mods that change core content. Do not update a modded server the minute a patch lands.
• Do not remove a mod mid-campaign. A campaign save that references a modded submarine or items may fail to load without it.
• Custom submarines are mods too, or .sub files in a submarine folder; everyone needs the same file for that sub to be selectable.

What to do when a mod update breaks has the general routine for a server that will not start after an update.

Campaign saves and backups#

A multiplayer campaign is the thing worth protecting on a Barotrauma server. The server saves campaign progress - money, reputation, the submarine and its upgrades, the crew - to a save file in the game's multiplayer save folder under the user data directory, between rounds and when the campaign ends. A crashed round usually costs that round's progress, not the campaign.

• Back up the campaign saves folder on a schedule and before every update. Updates sometimes change save handling, and a campaign that will not load is a campaign lost.
• Back up `serversettings.xml`, `config_player.xml` and the permissions files too. With those and a mod list, a fresh install is your server again.
• Keep copies off the machine. Backups that actually restore explains why copies next to the original do not count.

Several campaigns can exist side by side, and the lobby lets a permitted player choose which to load. Name them clearly; "Campaign 3" means nothing six weeks later.

On RE:NODE every game server has SFTP and a file editor for the XML files, backup slots stored off the machine and restored with a button, and a Schedules tab that can chain a backup and a restart. Barotrauma is not in the catalogue, so this describes the panel, not a Barotrauma plan.

Troubleshooting#

Players wait in the lobby and nothing happens. Nobody has permission to start a round. Give someone a rank, or enable autorestart or startwhenclientsready.

The server is not in the list. public is false, or the query port is closed. Test a direct join to separate a listing problem from a network one.

Players are refused with a version or content mismatch. The game updated and the server did not, or a mod differs. Update with SteamCMD and check the enabled package list.

The server fails at start after adding a mod. The mod is broken or incompatible with this version. Remove its line from config_player.xml and start again.

Settings changed in the file are lost. You edited while the server ran and it saved its own copy. Stop, edit, start.

Rounds lag on a large submarine. Too many devices and wires, or a level full of creatures, on one core. A smaller sub or fewer heavy mods helps more than memory. CPU vs RAM for game servers covers why.

FAQ#

How many players can a Barotrauma server hold?

Sixteen is the normal maximum crew, and the submarines and missions are designed around crews up to that size. Most community servers run 8-16.

Do players need to download mods manually?

No. When a player joins, the game offers to download missing content from the Workshop or the server. They still need the download to finish before they can play.

How do I make myself admin on a dedicated server?

From the server console, give your player the admin rank with giverank. After that you can manage everyone else from the in-game player list.

Where does the server keep campaign progress?

In the multiplayer save folder under the game's user data directory on the server. Back up that folder, not just the server install.

Does the Barotrauma server need a Steam account?

No. It downloads anonymously through SteamCMD. Players need the game.