Swarm Hosts / Guides

Valheim

Valheim uses a multi-port UDP layout. Swarm Hosts reserves the base game port and the next port together for normal play, and also reserves base+2 so crossplay can be enabled without changing the Swarm Server shape later.

Basics you should know

  • Default protocol: UDP
  • Typical ports: base port, base+1, and optional crossplay base+2
  • Persistent data: /config
  • World saves: /config/worlds_local
  • Recommended resources: 4 CPU and 8 GB RAM (2 CPU and 4 GB are the enforced minimum)
  • Ready signal: a successful local A2S query on base+1

Tip

Set a unique password with at least 5 characters or the dedicated server will refuse to start. Swarm Hosts does not supply a shared default password.

Launch

  1. Open Launch and choose Valheim.
  2. Select a Swarm Host or Swarm Zone and set the resource limits.
  3. Set Server name, World name, and Server password.
  4. Review Public listing and leave Crossplay disabled unless you need non-Steam clients.
  5. Choose Launch Valheim and confirm the launch review.

Use Settings → Valheim Settings to change the managed values after launch. Saving settings restarts or recreates the server and disconnects players.

Ports

  • Game port: auto-assigned UDP base port
  • Companion server port: auto-assigned UDP base+1
  • Crossplay backend port: reserved as UDP base+2

Note

Swarm Hosts assigns all three ports together. Share the base UDP port with players for direct join.

Data you may want to manage

  • Worlds: /config/worlds_local
  • Admin list: /config/adminlist.txt
  • Ban list: /config/bannedlist.txt
  • Permitted list: /config/permittedlist.txt

Valheim access-list entries use one case-sensitive platform user ID per line, in the form [Platform]_[User ID] (for example, Steam_76561198000000000). You can obtain the value from the server log or Valheim's F2 player list.

Permitted list becomes an allowlist

As soon as the permitted list contains an entry, every player not on that list is excluded. Removing the last entry allows everyone again. Server Actions save access-list changes, but they remain pending until you restart the Valheim server. These actions do not restart the server automatically.

Server Actions

Open Server Tools → Actions to check the server, manage access lists, or make a backup. Choose an action and fill in its fields; raw commands and arbitrary file paths are not accepted.

  • Server status reads the local A2S endpoint and reports the player count, capacity, password flag, query port, and detected Steam build when available.
  • Access lists shows the managed administrator, banned, and permitted IDs to administrators.
  • Add/remove administrator, ban/unban, and permit/remove permitted player update only the three fixed files above. Administrator and permitted-list changes require owner approval; ban changes require administrator confirmation.
  • Back up now creates a world ZIP archive and checks its integrity before reporting success.

RCON, F5 console automation, live access-list reload, and plugin loading or updating are unavailable in Server Actions. Use the normal Swarm Server restart control after an access-list action.

Backups

Platform backups include world data and all three access lists. Back up now also keeps world ZIP archives under /config/backups, retaining at most 20 archives and removing archives older than 14 days. Schedule platform backups through Files & Backups → Backups and keep an independent copy of important worlds.

Mods and plugins

Swarm Hosts does not currently provide a managed Valheim plugin installation workflow. BepInEx plugins require a compatible loader and can execute server code. Uploading plugin files through File Manager alone does not install that loader or make the plugins persist across server recreation.

Keep a backup of the world before experimenting with plugins. Plugin discovery, compatibility checks, dependency resolution, automatic updates, and rollback are unavailable.

Runtime and version behavior

The dedicated server is installed from Steam at startup. Valheim does not currently offer exact historical game-version selection or rollback. Check the running version after updates and verify that players can join.

Connect

Players can join through Valheim's Join IP flow using the player address and base UDP port shown on the Swarm Server page:

<PLAYER_HOSTNAME_OR_IP>:<BASE_PORT>

Source and provenance

Swarm Hosts installs the Valheim dedicated server from Steam. The server binaries come from Valve's Steam distribution path for Valheim dedicated servers, while Swarm Hosts handles the setup, launch settings, port assignment, and persistent storage for you.

Use the access-list guidance above when managing administrators, bans, and permitted players. Restart after changes so the game reads the updated files.