Valheim Server Configuration Guide

This article covers the configuration options you've got on a Valheim dedicated server, what each one actually does, and where to set it. It's the long-form reference. Everything Valheim takes as a setting is a launch argument: there's no server config file to edit, so on your own box you build the launch line by hand, and on a LOW.MS server the Manage tab holds a form and we build the line from it when the server starts. If you just want a recommended setting profile, the best server settings blog has those. If you are not with us yet, our Valheim server hosting plans put every option below in the panel.

The basics

These are the options you'll want sorted on day one. On our panel they're the General group on the Manage tab.

Server Name

What appears in the in-game server browser. Pick something descriptive so your friends can spot it. Set via the -name launch parameter.

Server Password

The password players need to enter to join. Two rules to know:

• Five characters minimum. That's Valheim's own floor, and the panel enforces the same number.
• The password can't appear inside the world name or the seed name. Note which way round that runs. It's not that the password can't contain the world name, it's that the password can't be a substring of either one. World called Midgard, password gard? Rejected. This catches people out a lot, and the seed name half of it catches out even more people because most of us never look at it.

It isn't quiet about the failure, at least. The server writes Error bad password: to the log and then exits, so if your server dies within seconds of a password change, open the log (the Console tab, on our panel) and look for that line.

Set via -password.

World Name

The world the server loads. Since Valheim 1.0 that's a folder with this name inside worlds_local, rather than the .db and .fwl pair older worlds used. Change this and the server will load a different world (or create a new one with that name). Your old world is still there. Switch the name back any time and you're back on it. Set via -world.

Gotcha: on our panel the World Name field offers suggestions from your worlds folder, but they were built for the pre-1.0 pair of files. Since 1.0 a world is a folder, so the suggestions won't list it, and the field can even say a world doesn't exist when it's sitting right there. A fix is on the way. Until then, type the name and check the Files tab (config/valheim/worlds_local/) rather than trusting the notice, and don't pick a suggestion ending in _backup_ and a date, because that's the snapshot Valheim took just before converting your world to 1.0.

Public Server

-public 1 lists the server in the community browser, -public 0 keeps it off the list. Either way it's joinable by address. On our panel it's the Public Server setting in the General group.

Server Port

Valheim always uses two consecutive UDP ports: the launch port and port+1, the second one being the Steam query port. Self-hosting at home, the default is 2456 and you'd forward UDP 2456-2457 on your router.

On a LOW.MS server you don't pick it. The port is assigned when the server is provisioned and shown on the strip at the top of the server page; ours look like 27515, 27520, 27525 and so on, and a server on 27515 also occupies 27516.

Crossplay

-crossplay moves the server's networking from Steam onto Iron Gate's PlayFab backend, which is what lets Xbox, PlayStation 5, Switch 2 and Game Pass players join. They connect with a six-digit join code the server prints on startup, which changes every start. The cost is that everyone, Steam players included, then connects through the relay rather than directly, which can add a little latency. Off unless you need it.

On our panel it's the Crossplay checkbox in the General group. Tick, save, restart, and the current join code appears on the Join your server card on the Overview tab. One temporary exception: Iron Gate couldn't get the 1.0.12 hotfix onto Switch 2, so Switch 2 players can't play with anyone on 1.0.12 for now.

And one myth while we're here: crossplay does not stop BepInEx loading. You'll see this claimed a lot and it isn't true. BepInEx hooks in when the game's runtime starts, before Valheim has read a single launch argument, so a flag can't switch it off. What crossplay actually breaks is individual mods that assume every player is on Steam, anything keying off SteamID64 or Steam networking. That, plus console players not being able to install mods at all, is the real reason to leave crossplay off a heavily modded server.

World modifiers

World modifiers arrived with Hildir's Request in August 2023 and have been tweaked since. They adjust how the world plays, and while they're offered at world creation you can change most of them later from the in-game world menu, or set them on the server's launch line with -preset and -modifier.

The five categories Iron Gate ships are:

• Combat: veryeasy, easy, normal (default), hard, veryhard
• DeathPenalty: casual, veryeasy, easy, normal (default), hard, hardcore
• Resources: muchless, less, normal (default), more, muchmore, most
• Raids: none, muchless, less, normal (default), more, muchmore
• Portals: casual, hard (default), veryhard

Plus the presets, which set all five at once: normal, casual, easy, hard, hardcore, immersive and hammer.

Combat

Adjusts how hard enemies hit and how durable you are. Hard and Very Hard make enemies hit noticeably harder and reduce player damage; Easy and Very Easy go the other way. Iron Gate has not published exact percentage tables for these, so I'd rather not invent numbers.

Death penalty

Controls what happens when you die.

• Casual: no skill loss.
• Easy / Very Easy: reduced skill loss.
• Normal: Valheim's default.
• Hard: increased skill loss.
• Hardcore: permanent loss of all items and skills on death. Brutal.

Portal restrictions

The most argued-over setting in Valheim.

• Casual: everything goes through portals, ores included.
• Hard (default): ores and metals can't be portalled. The vanilla experience.
• Very Hard: the strictest setting, which the game labels no portals.

Worth being precise here, because these two things get conflated constantly: the Portals modifier is about what portals let through, from carry-anything at Casual up to the strictest setting, which the game labels no portals. If you want portals gone for certain, the unambiguous switch is the NoPortals world key, covered under World rules below.

Resource rate

Adjusts how generous resource nodes are when you mine, chop or pick.

• Much Less / Less: slower, more survival-focused.
• Normal: default.
• More / Much More / Most: for groups who'd rather build than grind.

Raid frequency

How often the game throws raid events at your bases.

• None: no raids.
• Less / Much Less: occasional raids.
• Normal: default cadence.
• More / Much More: frequent raids.

Setting modifiers on your own server

Chain them on the launch line:

-preset normal -modifier raids none -modifier deathpenalty casual -modifier portals casual

The most common mistake by a distance is typing raids none without the -modifier in front of it. The server starts fine, the setting does nothing, and you spend an evening wondering why raids are still turning up.

Setting modifiers on a LOW.MS server

The World Modifiers group on the Manage tab is the same thing as a dropdown for the preset and a row of buttons for each modifier. World Preset sets every modifier at once (Standard is Iron Gate's normal). Combat Difficulty, Death Penalty, Resource Drops, Raids and Portals each start on Use preset; pick anything else on one of them and it overrides what the preset chose for that one dial, leaving the rest alone. The values are passed on every start, so the panel's values are the world's values and there's no hidden state to guess at. Change any of them back whenever you like.

There's a Custom Modifiers group under it for the finer dials Iron Gate exposes as world keys: Player Damage, Enemy Damage, Enemy Speed & Size, Enemy Level-Up Rate, Resource Rate, Skill Gain Rate, Skill Loss on Death and Items on Death, each as a percentage or a choice. A Combat Difficulty level, or a preset that changes combat, overrides the combat ones, so leave those on Use preset if you've set a difficulty.

World rules

Separate from the modifiers are the boolean world keys, set with -setkey. Iron Gate documents four (nobuildcost, playerevents, passivemobs, nomap); fire and NoPortals work the same way without being on that list. -setkey takes an arbitrary string, which is why undocumented keys work.

On our panel they're the World Rules group on the Manage tab: Free Building, Player-Triggered Events, Passive Creatures, No Map, Fire Hazard (Ashlands only, or everywhere) and No Portals.

They look like the modifiers above and they mostly behave like them, with one wrinkle worth knowing. Valheim writes each of these into the world save as a key, and what happens when you switch one off depends on whether the launch line carries a -preset. With a preset, the world's modifier keys are rebuilt from the launch line on every start, so a key you drop is gone at the next start. Without one, the launch line only ever adds, and the world keeps a key until something removes it. Our launch line always carries the preset, so on a LOW.MS server switching a rule off in the panel switches it off in the world at the next restart. If you're self-hosting without a preset and a rule has stuck, an admin can remove it in game (devcommands, then removekey nomap or whichever key), or start the server once with -resetmodifiers. Don't reach for resetkeys to do it: that command clears every global key, boss kills included. resetworldkeys is the one that clears only the modifier keys. Valheim world modifiers explained goes through all of this, key by key.

Player limit

Valheim's official cap is 10 players per server. The 10-cap is a deliberate Iron Gate design choice: Valheim's networking does some peer-to-peer lifting that doesn't scale well past that. Mods like Azumatt/MaxPlayerCount can lift the cap, but expect performance issues and the occasional weird sync bug if you do. Installing it goes through the mod installation process like any other mod.

Server launch parameters

On a LOW.MS server you don't type these (we build the launch line and you fill in the form), but it's useful to know what each one is doing. These are the parameters Iron Gate documents:

You can chain -modifier and -setkey multiple times to set several at once.

One of those is worth knowing the value of on our servers. We point -savedir at config/valheim inside your server's files, which means your worlds end up in config/valheim/worlds_local/ (on 1.0, one folder per world). There's no worlds_local at the top level, so if you go looking for a save and can't find one, that's why.

Admin commands

Once you've added yourself to the admin list and restarted the server, the in-game console (press F5) gives you the basic admin command set. The commands that work on a vanilla dedicated server are:

kick, ban, unban, banned and save are the admin set proper. Your client hands them to the server, which checks your ID against adminlist.txt before doing anything; if you're not on the list you get "You are not admin" back and nothing happens. save is worth knowing about: it forces an immediate world save and restarts the interval timer, which is the thing to run before you go poking at anything risky.

Beyond those, an admin who types devcommands first also gets the world-key and modifier commands that the server runs on your behalf: setkey, removekey, listkeys, resetworldkeys, resetkeys, setworldmodifier, setworldpreset, players, skiptime, sleep, restartparty and genloc. Mind the two resets: resetworldkeys clears the modifier keys only, while resetkeys clears every global key including boss progression. The cheat set (god, fly, spawn and friends) stays off on a dedicated server whatever you type.

lodbias is the odd one out and worth calling out because other sites list it as a server setting. It isn't. It changes the rendering quality on your own machine and does nothing to the server at all.

One command you will see in other people's dedicated-server lists that genuinely doesn't work: noportals. It exists, but Valheim marks it host-only, so it runs in single-player and on a locally-hosted game and answers "not valid in the current context" when you're connected to a dedicated server. Turning portals off on a dedicated server is the NoPortals world key instead (the No Portals rule on our panel). The Portals modifier's strictest setting is labelled no portals too, but the key is the one that leaves no room for doubt.

A note on the cheat commands: Iron Gate intentionally restricts vanilla devcommands (god mode, fly, exploremap, spawn, etc.) to single-player and locally-hosted games. They do not work on a dedicated server out of the box, and toggling devcommands on a client connected to one won't change that. If you want them, install the Server devcommands mod by Jere Kuusela, which re-enables the full set for admins on a dedicated server. Install it on your own client as well as the server: the server copy is optional but unlocks the full set.

For the full vanilla command list see the Valheim Admin Commands article.

Permissions: adminlist, bannedlist, permittedlist

Valheim manages permissions through three text files in the save directory, next to worlds_local. On a LOW.MS server the place to manage them is the Players tab, one row per player with a toggle for Admin, Banned and Whitelist, plus an Add by SteamID64 form for players who haven't connected yet. The admin list and whitelist files are generated from that tab on every start and the ban list is kept in step with the file, so edit all three there rather than in the file manager, and remember that changes apply on the next start.

adminlist.txt

Steam64 IDs of players who should have admin access. One ID per line:

76561198012345678
76561198087654321

Players joining a crossplay server from Xbox, PlayStation or Switch don't have a Steam64 ID, so they go in by their platform ID instead (Xbox_ followed by a number, case sensitive). Full walkthrough: Valheim adminlist.txt guide.

bannedlist.txt

IDs of banned players. Entries are added automatically when you use the ban command in the console, and on our panel the Players tab and the console end up in the same list.

permittedlist.txt

If you want a whitelist-only server, add the IDs of allowed players to this file. Once it has any entries, only those IDs can connect. Leave it empty for a normal password-protected server.

Valheim 1.0 note: 1.0 added a new player ID format (Iron Gate's example is V_123456789), and on the 1.0.7 launch build bannedlist.txt and permittedlist.txt only recognised that style and ignored older Steam_ entries. The 1.0.12 hotfix fixed it, so if either list seems to be ignoring people, update the server before you rewrite anything.

Backups

There are two separate things here and it's worth knowing which is which, because people tend to assume one covers the other.

Valheim's own backups. The game keeps a rolling set of world backups alongside the save (since 1.0, each one is its own folder), controlled by the -backups, -backupshort and -backuplong parameters above. The defaults give you 4: one short (2 hours old) and three long (12 hours apart). On our panel they're sliders in the Saves & Backups group on the Manage tab, along with the save interval. For most groups the defaults are fine.

LOW.MS backups. The Backups tab copies your worlds and mod settings off the server, and Restore puts them back with the server stopped. Create backup is a button you press: there's no automatic schedule running behind it, so if you've never opened the tab, you don't have one. Putting it on a timer is a two-minute job under Scheduled tasks on the Settings tab, and it's the sort of thing to sort out before you need it rather than after. Backing up and restoring a Valheim server goes through both systems properly.

Performance tips

A few things that have come up in support tickets enough times that they're worth flagging up front:

• Big builds are the main lag source. Each building piece is tracked and synced. Sprawling castles with thousands of pieces will start to chug, especially when players enter the area.
• Tamed creatures count too. Each tamed animal is an active entity. A breeding farm with dozens of boars can hurt performance more than the same number of building pieces.
• Terrain modifications are sticky. Heavy use of the hoe or pickaxe on terrain creates terrain mod data that gets synced to anyone walking through. Try not to terraform every square meter of your base.
• Restart weekly. Optional, but it clears memory and resets entity states. Long-running servers benefit from a quick restart even if there's no obvious problem, and a Restart task under Scheduled tasks will do it for you at whatever hour suits.

If you're seeing real performance issues, the Valheim Troubleshooting Guide walks through diagnosing them.

Need help?

Open a ticket from the panel and we'll dig in. Knowledgebase articles only go so far: if your specific server is doing something weird, support can poke at it directly.