Install the server
The server is a Steam tool, not a game. In your Steam library, open the top left dropdown and tick the Tools box, then scroll to Valheim Dedicated Server and install it. To find the folder afterwards, right click that entry and choose Manage, then Browse local files.
On Linux, Iron Gate lists three extra packages the server needs beyond what the Steam client pulls in: libatomic1, libpulse-dev and libpulse0. If your distribution is older than the server's minimum libraries, Iron Gate's documented alternative to upgrading the whole system is to run it through the bundled docker_start_server.sh script instead.
Edit a copy of the start script, not the original
Before the server will do anything useful you have to put your settings into start_headless_server.bat on Windows, or start_server.sh on Linux. Iron Gate's own advice is to copy the file first and edit the copy, "since the original file will be reset each time it is updated in Steam". The trade is that Steam's shortcut only points at the original filename, so your copy has to be launched by hand.
All the settings sit on one line, the one beginning start valheim_server. When the window prints Game server connected, the server is up and taking players.
Stopping it correctly matters more than it sounds. Iron Gate is blunt: close it with CTRL+C in the command window. "If you close it by clicking the X in the window frame the Server may keep running in the background, we don't really know!" A second copy of the server holding the same world is how worlds get rolled back.
The arguments worth knowing
| Argument | What it does |
|---|---|
-name "My server" | The name shown in the server list. |
-port 2456 | The port the server listens on. See the note below about the second port. |
-world "Dedicated" | Creates a world with that name, or loads an existing one of the same name. |
-password "Secret" | Sets the join password. |
-public 1 | Default. Makes the server visible in the browser. Set it to 0 for join-by-IP only. |
-savedir [PATH] | Overrides where worlds and permission files are stored. |
-saveinterval 1800 | How often the world saves, in seconds. Default is thirty minutes. |
-crossplay | Runs on the crossplay backend instead of the Steam one. |
-preset hard | World modifier preset: Normal, Casual, Easy, Hard, Hardcore, Immersive or Hammer. |
World modifiers are worth a second look before you generate anything, because a preset overwrites earlier modifiers and has to be set first. After a preset you can still set individual ones with -modifier, covering Combat, DeathPenalty, Resources, Raids and Portals, and switch on flags like nobuildcost, playerevents, passivemobs and nomap with -setkey.
Ports, and the one people forget
Valheim does not use one port. Iron Gate states it directly: "Valheim uses the specified Port AND specified Port+1. Default Ports are 2456-2457." Forward both. A server that opens 2456 alone will look alive from the machine it runs on and invisible from everywhere else.
The crossplay backend changes this completely. On crossplay the server "transmits data via a relay server and therefore does not require Port Forwarding", and players can join by public address and port, by join code, or from the server list. The catch Iron Gate names is that on crossplay you cannot connect using a local address or a loopback address, which is exactly what someone testing on the same machine will try first and read as a broken server. If you are hosting several servers on one machine with the same port, give each one a unique -instanceid so they get unique PlayFab IDs.
Where the world and the permission files live
Unless you set -savedir, the default save path is %USERPROFILE%/AppData/LocalLow/IronGate/Valheim on Windows and ~/.config/unity3d/IronGate/Valheim on Linux. That folder is the thing to copy before any update, move, or experiment.
Three plain text files in the same place control access: adminlist.txt, bannedlist.txt and permittedlist.txt. One Platform User ID per line, in the form [Platform]_[User ID], and Iron Gate notes it is case sensitive. You can read the ID out of the server log or from in game with F2. One warning is easy to miss and hard to undo in a hurry: "adding a person on the permitted list will ban everyone else from the server."
Backups are handled for you but only lightly. The defaults keep four copies, one short one taken every two hours and three long ones twelve hours apart, tuned with -backups, -backupshort and -backuplong. That is a rollback window, not an archive. Keep your own copies somewhere else as well.
Updates
Valheim updates through Steam like any other tool, which is convenient and also the reason to keep your edited start script separate. When Steam refreshes the original script, an unmodified copy is exactly what you want to find there. Restart cleanly after every update and watch the console output through startup rather than assuming.
Self-hosting or renting
For a small crew, self-hosting Valheim is genuinely easy and genuinely free if you already have a machine that stays on. You keep the world files in your own hands, you can copy them anywhere, and the crossplay backend removes the router step that used to stop people.
What self-hosting costs you is availability and attention. The machine has to be awake whenever anyone wants to play, and it should not be the computer you are playing on. Some home connections cannot accept incoming connections at all, which no amount of port forwarding will fix. Every restart, update and crash is yours to catch. And nobody keeps backups as often as they intend to.
Renting moves those chores rather than removing them. The world settings, the modifiers, the admin list and the backups you actually care about are still your decisions.
Where RadarHost fits
RadarHost rents Valheim servers hosted in Beauharnois, Quebec, Canada. There are three plans, Standard, Premium and Diamond, priced in Canadian dollars, with no setup fee and cancel any time. Renting changes who keeps the machine on, not how the game runs or how the arguments above work. After payment, our team reviews the order and emails setup details or next steps within 24 hours. Current plans and prices are on the Valheim availability page.