Valheim 1.0 Dedicated Server Setup: Windows, Linux and Crossplay

Valheim provides a standalone dedicated-server application for persistent 1–10 player worlds. The current official setup uses Valheim Dedicated Server from Steam's Tools library, then configures the supplied Windows or Linux launch script.

Valheim 1.0 launches September 9, 2026. This guide covers the currently documented server application and identifies launch-day details that still require rechecking.

Before you start

You need:

• a Windows or Linux machine that can remain online;
• Steam access to install Valheim Dedicated Server;
• permission to edit launch files and firewall settings;
• a server name, world name, and strong password;
• enough storage for the application, worlds, logs, and multiple backups;
• a rollback copy before importing or updating an important world.

Iron Gate does not publish a dedicated-server CPU or memory minimum in its server guide. Do not treat an unofficial hosting calculator as a guaranteed requirement. For capacity planning, see the current server requirements scope.

Install through Steam Tools

1. Open the Steam Library.
2. Use the library filter and enable Tools.
3. Find Valheim Dedicated Server.
4. Select Install.
5. After installation, use Manage → Browse local files to open the server directory.

The application includes start_headless_server.bat for Windows and start_server.sh for Linux.

Protect the supplied launch file

Make a copy of the supplied launch script and edit the copy. Iron Gate warns that Steam updates reset the original file, which can erase custom arguments.

The copied file cannot be launched through Steam's normal shortcut because that shortcut targets the original filename. Start the copy directly or through your own service configuration.

Windows configuration

1. Copy start_headless_server.bat to a clearly named file such as start_valheim_production.bat.
2. Open the copy in a plain-text editor.
3. Find the line that starts the server executable.
4. Set the name, port, world, password, visibility, and networking arguments.
5. Save the file and run it.
6. If Windows Firewall prompts, allow the server on the network profiles appropriate to your environment.
7. Wait for Game server connected before testing a client.

Do not publish the launch file when it contains a real password.

Linux configuration

1. Copy start_server.sh to a production-specific filename.
2. Edit the copied script and set the launch arguments.
3. Ensure the script is executable.
4. Run it from the server directory or manage it through an operating-system service.
5. Wait for Game server connected.

Iron Gate lists libatomic1, libpulse-dev, and libpulse0 as additional Linux packages. The dedicated server requires at least GLIBC 2.29 and GLIBCXX 3.4.26. The official distribution also includes a Docker startup script for systems where a container is preferable.

Launch-command example

The exact wrapper differs between Windows and Linux, but the server arguments follow this pattern:

valheim_server -nographics -batchmode -name "My Valheim Server" -port 2456 -world "Dedicated" -password "replace-with-a-strong-password" -public 1 -crossplay

Core arguments:

Use plain straight quotation marks in scripts. Keep each flag separate from its value and do not include the square brackets shown in argument documentation.

Ports and firewall

Valheim uses the configured port and the next port. With the default base port, that is:

2456–2457

For the Steam backend, the range must be reachable from the internet, which normally requires firewall permission and router port forwarding. Router interfaces differ, so use the router or ISP documentation rather than copying instructions for another model.

With -crossplay, PlayFab relays traffic and does not require port forwarding for outside access. The port still distinguishes multiple servers on the same public IP.

Crossplay configuration

Add -crossplay to allow supported non-Steam platforms to join. Without it, the Steam backend is used and only Steam users can see and join the server.

Crossplay clients can join through the public address and port, a join code, or the server list. They cannot connect through a local or loopback address. See the full Valheim crossplay guide.

World and save locations

The official defaults are:

Use -savedir to place worlds and permission files somewhere else. When using Iron Gate's Docker script, the default game-data volume is valheim_server_data; it can be changed to a host filesystem path.

Use an existing world

The -world argument can select an existing world by name. Before importing:

1. Stop both the source game and destination server.
2. Back up the source and destination.
3. Copy the complete world-file set, not a single file chosen by extension.
4. Place it in the destination's active save directory.
5. Set -world to the world name.
6. Start the server and confirm the expected seed, builds, and progression.

Use the detailed local-world to server migration checklist.

Automatic saves and backups

The current documented defaults are:

Automatic backups are valuable, but they are not a substitute for an offline copy. A configuration mistake, disk failure, or accidental deletion can affect the live directory and its rotating backups together.

Before 1.0, follow the world backup and restore guide.

Permissions and player lists

The save directory contains:

• adminlist.txt for administrators;
• bannedlist.txt for banned users;
• permittedlist.txt for an allowlist.

Add one case-sensitive Platform User ID per line. Iron Gate warns that adding someone to permittedlist.txt excludes everyone not listed.

World modifiers

The dedicated server supports preset and individual modifier arguments. For example:

-preset hard
-modifier raids none
-setkey nomap

A preset overwrites previous modifiers. When combining a preset with individual modifiers, put the individual modifier after the preset. Valid values can change, so use the current official server guide rather than inventing a value.

Some modifiers affect achievement eligibility in 1.0. Review the official 1.0 FAQ before applying them to an achievement-focused world.

Multiple server instances

Use different ports, world names, save paths, and launch files for simultaneous instances. When multiple PlayFab servers use the same port and MAC address, Iron Gate documents -instanceid for assigning each server a unique PlayFab ID.

Never point two running server processes at the same writable world files.

Updating to Valheim 1.0

1. Announce downtime and stop logins.
2. Shut down with CTRL+C and wait for the process to exit.
3. Copy the world, permission files, and custom launch script offline.
4. Record the current application and mod versions.
5. Update the dedicated-server application.
6. Recheck the supplied script for new or changed arguments.
7. Start the copied production script.
8. Confirm the version, world, visibility, join code, and crossplay behavior.
9. Keep the rollback copy until the community accepts the update.

The official server guide specifically recommends CTRL+C; closing the window can leave the process running. Continue with the server update guide.

Rollback and restore

Do not assume a world saved by a newer version is backwards-compatible with an older server. A safe rollback restores the matching application environment, world backup, configuration, and mod set as a group.

Never test a rollback against the only remaining copy.

Troubleshooting

The server never reaches “Game server connected”

Review the launch line for broken quotes or missing values, then inspect the server output. Confirm required Linux libraries where applicable.

Steam users outside the network cannot connect

Check the selected port plus port +1, the host firewall, router forwarding, and public IP. These checks apply to the Steam backend.

Crossplay users cannot connect locally

PlayFab does not accept local or loopback addresses. Use the public address and port, join code, or server list.

The wrong world loads

Confirm -world, the active save directory, and the identity of the copied world files. A -savedir override changes where the server looks.

The server is missing from the browser

Confirm -public 1, wait for Game server connected, and try the direct join method. Use the server-not-showing guide.

Managed hosting alternative

Running a server means maintaining updates, firewall or relay settings, backups, availability, and recovery. Groups that prefer a managed service can review the Valheim server-hosting comparison criteria.

That hosting page does not rank providers until current plans, renewal prices, backup policies, crossplay, world export, and affiliate relationships have been verified.

Official sources

• Valheim dedicated-server guide
• Valheim crossplay FAQ
• Valheim 1.0 FAQ