---
title: "Minecraft server.properties Explained (Java 26.3)"
url: https://1up-servers.com/en/blog/minecraft-server-properties-explained/
lastmod: 2026-10-26
---

# Minecraft server.properties Explained: Every Key, Default and Panel Field

Every server.properties key of Minecraft Java 26.3 with its default from the Minecraft Wiki, what it does, and which panel field or file sets it on 1up.

By [Baurtock](https://1up-servers.com/en/blog/author/baurtock/)
Updated Oct 26, 2026 · 8 min read

Read in[es](https://1up-servers.com/es/blog/server-properties-de-minecraft-explicado/)[en](https://1up-servers.com/en/blog/minecraft-server-properties-explained/)[pt-BR](https://1up-servers.com/pt-br/blog/server-properties-minecraft/)[de](https://1up-servers.com/de/blog/minecraft-server-properties-erklaert/)[it](https://1up-servers.com/it/blog/server-properties-minecraft-spiegato/)

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server.properties is the plain-text file where a Minecraft Java server keeps its settings, one `key=value` per line: game mode, difficulty, player limit, view distance, whitelist and about sixty more. This guide lists every key in Java 26.3 with its default from the Minecraft Wiki, and where each one is changed.

The file is the same on any host. If you run a [Minecraft Java server](https://1up-servers.com/en/minecraft-java-edition/) with us, most keys have a field in the panel and the rest can be edited in **Files**; if you have no server yet, our [free Minecraft server guide](https://1up-servers.com/en/blog/how-to-make-a-free-minecraft-server/) gets you one first.

- **Where it is:** in the server's root folder, next to the `world` folder. Changes apply after a restart.
- **Four keys are gone:** since Java 1.21.9, `pvp`, `allow-nether`, `spawn-monsters` and `enable-command-block` are gamerules, not properties.
- **26.3 changed a default:** `white-list` is now `true` on a new vanilla server.
- **On 1up:** the panel rewrites the keys it manages at every start, so change those in the **Game** and **Server** tabs, and only the others in **Files**.
- **Leave alone:** `server-port`, `enable-rcon`, `rcon.port` and `rcon.password`; the panel and console depend on them.

## 1. How the file works on 1up

Every default in this guide comes from the [Minecraft Wiki's server.properties page](https://minecraft.wiki/w/Server.properties), checked on 2026-10-13. The file is read once at startup, so any change, from the panel or by hand, needs a restart, except the few panel fields marked **Instantly**.

Our servers run the itzg Minecraft image. Its [documentation](https://docker-minecraft-server.readthedocs.io/en/latest/configuration/server-properties/) explains that properties given as variables are written into the file at every start, while "an unset variable is ignored and the existing server property is left unchanged". In practice:

- **Keys with a panel field** are written from the panel at every start. If you edit them in **Files**, the panel puts its value back on the next start. **Game → Advanced → Generated file** shows those keys as the panel writes them.
- **Keys without a panel field** keep whatever you write in **Files**. Open `server.properties` in the file editor, change the line, save and restart.

## 2. Gameplay keys

| Key | Default (wiki) | What it does | On 1up |
| --- | --- | --- | --- |
| `gamemode` | `survival` | Default game mode for new players | **Game → Match → Game mode** (survival, creative, adventure) |
| `difficulty` | `easy` | Mob damage, hunger, poison | **Game → Match → Difficulty**, applies instantly; our default is `normal` |
| `hardcore` | `false` | Hardcore mode on created worlds | **Game → Match → Hardcore** |
| `allow-flight` | `false` | Lets Survival players fly with mods; when off, players in the air for 5 seconds get kicked | **Game → Match → Allow flight** |
| `force-gamemode` | `false` | Puts players back in the default mode on every join | Files |
| `spawn-protection` | `16` | Protected square around spawn, 2x+1 blocks a side; `0` turns it off, and so does having no ops | **Game → World and creatures → Spawn protection** (0–64) |
| `op-permission-level` | `4` | Level given by `/op` | Files |
| `function-permission-level` | `2` | Level that datapack functions run at | Files |
| `player-idle-timeout` | `0` | Minutes before an idle player is kicked; `0` never | Files |

`allow-flight` sounds harmless, but the wiki warns that with it on, griefers "may become more common, because it makes their work easier". Leave it off unless a mod or plugin needs it.

### The four keys that became gamerules

The wiki's history records that Java 1.21.9 (snapshot 25w35a) removed four properties and "replaced them with game rules". Since 1.21.11 the rule names use snake_case, as our [Minecraft server commands guide](https://1up-servers.com/en/blog/minecraft-server-commands/) explains. A line for them in server.properties is ignored on 26.x, so the panel sends the gamerule instead, at start and when you save:

| Old property | Gamerule on 26.x | Panel field |
| --- | --- | --- |
| `pvp` | `pvp` | **Game → Match → PvP** (instantly) |
| `allow-nether` | `allow_entering_nether_using_portals` | **Game → World and creatures → Allow Nether** (instantly) |
| `spawn-monsters` | `spawn_monsters` | **Game → World and creatures → Spawn monsters** (instantly) |
| `enable-command-block` | `command_blocks_work` | **Game → Match → Cheats / commands** (instantly) |

The panel's "Cheats / commands" switch only turns command blocks on or off; operators can use commands either way. `spawn-animals` and `spawn-npcs` were removed earlier, in 1.21.2.

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## 3. World keys

| Key | Default (wiki) | What it does | On 1up |
| --- | --- | --- | --- |
| `level-name` | `world` | World folder to load or create | Leave as `world`; **Worlds → Activate** swaps worlds for you |
| `level-seed` | blank (random) | Seed for a new world | **Game → World and creatures → Seed (new worlds only)**, or **Server → World → Regenerate world** |
| `level-type` | `minecraft:normal` | Preset: normal, flat, large biomes, amplified | **Game → World and creatures → World type** (new worlds only) |
| `generator-settings` | `{}` | Custom generation, such as the layers of a flat world | Files |
| `generate-structures` | `true` | Villages and other structures in new chunks | Files |
| `max-world-size` | `29999984` | Furthest the world border can go from the centre | Files |
| `initial-enabled-packs` | `vanilla` | Datapacks enabled when the world is created | Files, before the first start |
| `initial-disabled-packs` | blank | Datapacks not auto-enabled at creation | Files, before the first start |
| `region-file-compression` | `deflate` | Chunk compression: `deflate`, `lz4` or `none` | Files |
| `sync-chunk-writes` | `true` | Writes chunks synchronously to prevent corruption after a crash | Files; leave on |

The seed and world type only matter when a world is generated. To change them on a world you already play, regenerate it: the dialog warns that "the current world is deleted", and offers a backup first on plans that keep backups. On Free there is none, so use **Export** on the **Worlds** tab first.

## 4. Players, access and chat

| Key | Default (wiki) | What it does | On 1up |
| --- | --- | --- | --- |
| `max-players` | `20` | Players online at once | **Game → Players → Max players**, capped by your plan's slots; our default is `4` |
| `online-mode` | `true` | Checks every player owns a Minecraft account | **Game → Players → Online mode** |
| `enforce-secure-profile` | `true` | Only players with a Mojang-signed key can join | **Game → Players → Secure profile**; turned off when Online mode is off |
| `white-list` | `true` since 26.3 | Only listed players can join | **Players → Whitelist on** |
| `enforce-whitelist` | `false` | Kicks online players who are not on a reloaded whitelist | Set together with **Whitelist on** |
| `motd` | `A Minecraft Server` | Line under the server name in the client's list | **Game → Presentation → MOTD** |
| `hide-online-players` | `false` | Hides the player list from status requests | Files |
| `enable-status` | `true` | Shows the server as online in the list | Files; leave on |
| `chat-spam-threshold-seconds` | `10` | Auto-kick threshold for chat spam; `0` off | Files |
| `command-spam-threshold-seconds` | `10` | Same for commands | Files |
| `log-ips` | `true` | Shows player IPs in the log | Files |
| `enable-code-of-conduct` | `false` | Shows code of conduct files from a `codeofconduct` folder | Files |
| `resource-pack`, `resource-pack-sha1`, `resource-pack-id` | blank | Server resource pack URL, checksum and id | Files |
| `require-resource-pack` | `false` | Disconnects players who decline the pack | Files |
| `resource-pack-prompt` | blank | Custom text on the pack prompt | Files |

Two of these need care. The wiki says `online-mode` "should only be set to false when the server is not connected to the Internet", because anyone could join with any name; on our servers it stays on unless you have a reason. And the [26.3 change](https://minecraft.wiki/w/Server.properties#History) of `white-list` to `true` means a fresh vanilla 26.3 server lets nobody but operators in until you add players. On 1up the **Whitelist on** switch decides instead, and a join password from **Server → Protection** turns it on for you.

## 5. Network and management keys

| Key | Default (wiki) | What it does | On 1up |
| --- | --- | --- | --- |
| `server-port` | `25565` | Port the server listens on | Do not change; your address and port are on the Overview |
| `server-ip` | blank | Address to bind to | Do not change |
| `enable-rcon`, `rcon.port`, `rcon.password` | `false`, `25575`, blank | Remote console | Do not change: the panel console uses RCON |
| `broadcast-rcon-to-ops` | `true` | Shows RCON output to online ops | Files |
| `broadcast-console-to-ops` | `true` | Shows console output to online ops | Files |
| `enable-query`, `query.port` | `false`, `25565` | GameSpy query protocol over UDP | Files, but our servers open only the game's TCP port |
| `network-compression-threshold` | `256` | Packet size from which packets are compressed | Files |
| `rate-limit` | `0` | Packets a player may send before a kick; `0` off | Files |
| `prevent-proxy-connections` | `false` | Kicks players whose ISP differs from Mojang's record | Files |
| `accepts-transfers` | `false` | Accepts transfer packets from another server | Files |
| `use-native-transport` | `true` | Linux packet optimisation | Files; leave on |
| `bug-report-link` | blank | URL for the client's report-bug link | Files |
| `management-server-*` | disabled, port `0` | Server Management Protocol (added in 1.21.9) | Not reachable: no extra port is open |
| `status-heartbeat-interval` | `0` | Heartbeat of the management server | Files |
| `enable-jmx-monitoring` | `false` | Exposes tick times over JMX | Files |
| `text-filtering-config`, `text-filtering-version` | blank, `0` | Chat filter used by Realms | Leave empty |

The itzg docs are blunt about RCON: "DO NOT change rcon.port via server.properties or integrations will break." On our servers that integration is the **Console** tab.

## 6. Performance keys

| Key | Default (wiki) | What it does | On 1up |
| --- | --- | --- | --- |
| `view-distance` | `10` (3–32) | Chunks sent to each player, as a radius | **Server → Performance → View distance** (4–16, default 10) |
| `simulation-distance` | `10` (3–32) | Chunks around each player where entities are updated | **Server → Performance → Simulation distance** (4–16, default 8) |
| `max-tick-time` | `60000` | Milliseconds one tick may take before the watchdog stops the server | **Server → Performance → Max tick (ms)** |
| `entity-broadcast-range-percentage` | `100` (10–1000) | How close entities must be to be sent to players | Files |
| `max-chained-neighbor-updates` | `1000000` | Limit of chained block updates | Files |
| `pause-when-empty-seconds` | `60` | Seconds with nobody online before the server pauses | Files |

For both distances, the wiki says: "If the player has major lag, this value is recommended to be reduced." Our [RAM guide](https://1up-servers.com/en/blog/how-much-ram-minecraft-server/) shows how view distance drives memory, and our [guide to fixing server lag](https://1up-servers.com/en/blog/fix-minecraft-server-lag/) covers simulation distance and Paper's own settings. On a Paper server, Paper adds files under `config/`; server.properties keeps the same keys.

Snapshots of 26.4 add `allowed-connection-ids`, `enable-legacy-status` and `status-contact-details`. They are not in 26.3, so they are left out of the tables above.

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Tested on Minecraft: Java Edition 26.3, the default version in our wizard, 2026-10-13. Defaults are quoted from the Minecraft Wiki that day; panel fields, ranges and our own defaults come from our production code.

**Change log**

- 2026-10-25: Starter has 4 GB (call to action updated from the live plans list).
- 2026-10-13: first version.

## Frequently asked questions

In the server's root folder, next to the world and logs folders. On 1up, open the Files tab: it is at the top level and the editor opens it directly.

About the author[Baurtock](https://1up-servers.com/en/blog/author/baurtock/)Founder, developer and support

NOT AN OFFICIAL MINECRAFT SERVICE. NOT APPROVED BY OR ASSOCIATED WITH MOJANG OR MICROSOFT.

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