Set up a Valheim dedicated server

Requirements

• A Linux server running Ubuntu 22.04/24.04 or Debian 12 with root access
• At least 2 CPU cores and 4 GB RAM for a small group – with mods and large bases rather 8 GB
• About 5 GB of free disk plus room for world backups
• Basic SSH experience (see Secure your SSH server)

Step 1: Create a user and install SteamCMD

The server runs as its own user, not as root. On Ubuntu, install SteamCMD from the multiverse repository:

# User for the game server
sudo useradd -m -s /bin/bash valheim

# 32-bit architecture and SteamCMD (Ubuntu)
sudo add-apt-repository multiverse
sudo dpkg --add-architecture i386
sudo apt update
sudo apt install -y steamcmd

# Libraries the Valheim server needs
sudo apt install -y libatomic1 libpulse-dev libpulse0

Step 2: Install the Valheim dedicated server

The dedicated server has Steam app ID 896660 and can be downloaded anonymously – you don't need a Steam account that owns Valheim.

sudo -u valheim -i

steamcmd +force_install_dir /home/valheim/server \
  +login anonymous \
  +app_update 896660 validate \
  +quit

Run the same command to update the server later. After a Valheim update, server and players must be on the same version, otherwise joining fails with “Incompatible version”.

Step 3: Create a start script

The install folder contains start_server.sh. Don't edit the original – an update overwrites it. Create your own copy:

#!/bin/bash
export templdpath=$LD_LIBRARY_PATH
export LD_LIBRARY_PATH=./linux64:$LD_LIBRARY_PATH
export SteamAppId=892970

./valheim_server.x86_64 \
  -name "My Valheim Server" \
  -port 2456 \
  -world "Midgard" \
  -password "secret123" \
  -public 1 \
  -saveinterval 1800 \
  -backups 4

export LD_LIBRARY_PATH=$templdpath

chmod +x /home/valheim/server/start_valheim.sh

Step 4: Open the ports

Valheim uses the given port and the next one – with the default that's 2456 and 2457 (UDP):

sudo ufw allow 2456:2457/udp
sudo ufw status

Players connect in-game via Join Game → Join IP with YOUR-SERVER-IP:2456. Public servers also show up in the community list – that can take a few minutes after start.

Step 5: Run it as a systemd service

To have the server start automatically after a reboot and save cleanly, create a service. Valheim saves when it receives SIGINT (like Ctrl+C) – hence KillSignal=SIGINT:

[Unit]
Description=Valheim Dedicated Server
After=network-online.target
Wants=network-online.target

[Service]
Type=simple
User=valheim
WorkingDirectory=/home/valheim/server
ExecStart=/home/valheim/server/start_valheim.sh
KillSignal=SIGINT
TimeoutStopSec=120
Restart=on-failure
RestartSec=30

[Install]
WantedBy=multi-user.target

sudo systemctl daemon-reload
sudo systemctl enable --now valheim
sudo journalctl -u valheim -f   # follow the log live

Step 6: Set admins

The permission files live in the valheim user's save folder ~/.config/unity3d/IronGate/Valheim/:

• adminlist.txt – admins, who may use e.g. kick and ban in the console (F5)
• bannedlist.txt – banned players
• permittedlist.txt – whitelist. Careful: as soon as anyone is listed here, everyone else is locked out.

One ID per line. Current versions expect the format Platform_ID, so for Steam players e.g. Steam_76561198… (the SteamID64). You'll find the exact spelling in the server log when someone connects, or in-game with F2. Restart the server after changes.

Step 7: Mods with BepInEx

Almost all Valheim mods rely on BepInEx, specifically the adapted BepInExPack_Valheim from Thunderstore.

1. Stop the server and take a backup (see step 8).
2. Download BepInExPack_Valheim and extract it into a separate folder.
3. Copy the contents of the BepInExPack_Valheim folder into the server directory /home/valheim/server.
4. Put the same parameters as in your start script into start_server_bepinex.sh, run chmod u+x start_server_bepinex.sh and point ExecStart in the systemd service to this script.
5. Start the server. If BepInEx messages show up in the log, it worked – the folders BepInEx/plugins and BepInEx/config are created on the way.
6. Copy mod DLLs into BepInEx/plugins/, restart, adjust settings in BepInEx/config/.

Step 8: Back up the world

A world consists of two files named after it: Midgard.db (the actual world) and Midgard.fwl (metadata such as the seed). Both live in:

/home/valheim/.config/unity3d/IronGate/Valheim/worlds_local/

With -backups Valheim keeps a few copies there automatically – but on the same server. Back up externally as well, e.g. with a daily cron job:

# Daily 05:00: archive the world, keep 14 days
0 5 * * * tar czf /home/valheim/backups/world-$(date +\%F).tar.gz -C /home/valheim/.config/unity3d/IronGate/Valheim worlds_local && find /home/valheim/backups -name 'world-*.tar.gz' -mtime +14 -delete

mkdir -p /home/valheim/backups

Download the archives to your PC or a storage service regularly, e.g. with scp or rsync. To restore: stop the server, copy both files back, start.

Upload your own world: a world from your local game lives on Windows in %USERPROFILE%\AppData\LocalLow\IronGate\Valheim\worlds_local. Copy the .db and .fwl into the folder on the server and set -world to exactly that name.