> For the complete documentation index, see [llms.txt](https://book.bsdcn.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://book.bsdcn.org/ask/flat/chapter-19-games-scientific-computing-and-professional-tools/di-19.2-jie-wo-de-shi-jie-minecraft-fu-wu-qi.md). # 19.2 Minecraft Server Minecraft is a sandbox game developed in Java. This section covers deploying the Minecraft server on FreeBSD. Setting up the server requires installing the Java runtime environment first; the server and client typically require the same Java version. ## Related File Structure ```sh / ├── etc/ │ └── rc.conf # System configuration file, includes minecraft service configuration ├── usr/ │ └── local/ │ ├── bin/ │ │ └── minecraft-server # Minecraft server executable │ └── etc/ │ └── minecraft-server/ # Minecraft server configuration directory │ ├── eula.txt # End-user license agreement file │ ├── java-args.txt # Java parameters configuration │ └── server.properties # Server configuration file ├── var/ │ ├── log/ │ │ └── minecraft-server/ # Log and debug output directory │ └── db/ │ └── minecraft-server/ # World files directory ``` ## Installing OpenJDK Note that outdated JDK versions are not supported by the server. This section was tested with JDK 21 and runs normally. Install OpenJDK 21 using pkg: ```sh # pkg install openjdk21 ``` Or compile and install OpenJDK 21 using Ports, which can be optimized for server hardware: ```sh # cd /usr/ports/java/openjdk21/ # make install clean ``` ## Using Ports or the Official Server Program There are two ways to set up a Minecraft server: Testing has confirmed that the [Minecraft official server](https://www.minecraft.net/en-us/download/server) is a pure Java program that runs directly on FreeBSD 15.0 after installing OpenJDK. The Ports version provides FreeBSD-specific integration, including service management scripts and default configuration files. You can also use **games/minecraft-server** available in Ports: ```sh # cd /usr/ports/games/minecraft-server/ # make install clean ``` View configuration information: ```sh # pkg info -D minecraft-server ``` Run the server: ```sh $ /usr/local/bin/minecraft-server …………part omitted………… [15:52:21] [ServerMain/WARN]: Failed to load eula.txt [15:52:21] [ServerMain/INFO]: You need to agree to the EULA in order to run the server. Go to eula.txt for more info. ``` The prompt indicates that you need to agree to the license agreement. Change `eula=false` to `eula=true` in the **/usr/local/etc/minecraft-server/eula.txt** file. Run the installed Minecraft server program again: ```sh # /usr/local/bin/minecraft-server Starting net.minecraft.server.Main [15:54:47] [ServerMain/INFO]: Environment: Environment[sessionHost=https://sessionserver.mojang.com, servicesHost=https://api.minecraftservices.com, name=PROD] [15:54:48] [ServerMain/INFO]: No existing world data, creating new world [15:54:49] [ServerMain/INFO]: Loaded 1290 recipes [15:54:49] [ServerMain/INFO]: Loaded 1399 advancements [15:54:49] [Server thread/INFO]: Starting minecraft server version 1.21.1 [15:54:49] [Server thread/INFO]: Loading properties [15:54:49] [Server thread/INFO]: Default game type: SURVIVAL [15:54:49] [Server thread/INFO]: Generating keypair [15:54:49] [Server thread/INFO]: Starting Minecraft server on *:25565 [15:54:50] [Server thread/INFO]: Using default channel type [15:54:50] [Server thread/INFO]: Preparing level "world" [15:54:53] [Server thread/INFO]: Preparing start region for dimension minecraft:overworld [15:54:53] [Worker-Main-2/INFO]: Preparing spawn area: 2% [15:54:54] [Worker-Main-2/INFO]: Preparing spawn area: 2% [15:54:54] [Worker-Main-3/INFO]: Preparing spawn area: 2% [15:54:55] [Worker-Main-1/INFO]: Preparing spawn area: 2% [15:54:55] [Worker-Main-2/INFO]: Preparing spawn area: 18% [15:54:56] [Worker-Main-1/INFO]: Preparing spawn area: 51% [15:54:56] [Worker-Main-3/INFO]: Preparing spawn area: 51% [15:54:56] [Server thread/INFO]: Time elapsed: 3317 ms [15:54:56] [Server thread/INFO]: Done (6.876s)! For help, type "help" ``` Press **Ctrl** + **C** to interrupt the program. ## Disabling Online Authentication Under the current default configuration, the server has online authentication enabled (`online-mode=true`). This mechanism communicates with the Mojang session server and Microsoft authentication service to verify player identity, ensuring: * Each player has a unique UUID assigned by Mojang/Microsoft, bound to their purchased account * Players cannot log in using another person's username * Bans and permission management are based on real account identity > **Warning** > > You should only use `online-mode=false` when you fully understand the risks and have deployed additional protective measures. If you need to allow players who have not purchased the game to connect in a LAN or testing environment, edit the **/usr/local/etc/minecraft-server/server.properties** file and change `online-mode=true` to `online-mode=false`. Then run the installed Minecraft server program again: ```sh # /usr/local/bin/minecraft-server Starting net.minecraft.server.Main [18:47:47] [ServerMain/INFO]: Environment: Environment[sessionHost=https://sessionserver.mojang.com, servicesHost=https://api.minecraftservices.com, name=PROD] [18:47:51] [ServerMain/INFO]: Loaded 1337 recipes [18:47:51] [ServerMain/INFO]: Loaded 1448 advancements [18:47:51] [Server thread/INFO]: Starting minecraft server version 1.21.3 [18:47:51] [Server thread/INFO]: Loading properties [18:47:51] [Server thread/INFO]: Default game type: SURVIVAL [18:47:51] [Server thread/INFO]: Generating keypair [18:47:51] [Server thread/INFO]: Starting Minecraft server on *:25565 [18:47:51] [Server thread/INFO]: Using default channel type [18:47:52] [Server thread/WARN]: **** SERVER IS RUNNING IN OFFLINE/INSECURE MODE! [18:47:52] [Server thread/WARN]: The server will make no attempt to authenticate usernames. Beware. [18:47:52] [Server thread/WARN]: While this makes the game possible to play without internet access, it also opens up the ability for hackers to connect with any username they choose. [18:47:52] [Server thread/WARN]: To change this, set "online-mode" to "true" in the server.properties file. [18:47:52] [Server thread/INFO]: Preparing level "world" [18:47:52] [Server thread/INFO]: Preparing start region for dimension minecraft:overworld [18:47:53] [Worker-Main-5/INFO]: Preparing spawn area: 0% [18:47:53] [Worker-Main-5/INFO]: Preparing spawn area: 0% [18:47:53] [Worker-Main-5/INFO]: Preparing spawn area: 0% [18:47:53] [Server thread/INFO]: Time elapsed: 1233 ms [18:47:53] [Server thread/INFO]: Done (1.709s)! For help, type "help" [18:48:34] [Server thread/INFO]: ykla[/127.0.0.1:37462] logged in with entity id 39 at (-1.5, 63.0, 1.5) [18:48:34] [Server thread/INFO]: ykla joined the game ``` ![Running Minecraft on FreeBSD](/files/3jRxYJG2lnlvYqWRJduT) ## Security Risks of Disabling Online Authentication Completely disabling Mojang/Microsoft account verification introduces the following serious security risks: 1. **Administrator account impersonation**: Anyone can enter an administrator (OP) username to log in directly, gaining full administrative privileges, items, and territories on the server. Since UUIDs are generated locally based on usernames (`OfflinePlayer:username`), the server cannot distinguish between a real administrator and an impersonator. 2. **Bans become completely ineffective**: Banned users only need to change their username to rejoin without purchasing a new account, rendering the ban mechanism useless. 3. **Whitelist becomes ineffective**: In offline mode, the whitelist only checks usernames rather than account identity, and cannot prevent impersonation. 4. **Extremely low barrier for bot attacks**: Attackers can generate random usernames in bulk for automated attacks without purchasing any Minecraft accounts. 5. **Player data loss risk**: In offline mode, UUIDs are bound to usernames rather than accounts. If a player changes their username, all their items, builds, permissions, and other data will be permanently lost. 6. **Risk of violating the Minecraft EULA**: Allowing players who have not purchased the game to connect may violate Mojang's End User License Agreement. 7. **Skins and licensed features unavailable**: In offline mode, all players' appearances display as the default Steve/Alex skins. If you genuinely need to use offline mode (e.g., in a closed LAN environment, or when using BungeeCord/Velocity proxy forwarding), the following mitigation measures are recommended: * Install authentication plugins (such as AuthMeReloaded) to require players to register passwords, preventing username impersonation * Use firewall restrictions to allow only trusted IP ranges to connect * Use plugins like CoreProtect to log all block operations for traceability and rollback * Use permission plugins like LuckPerms for fine-grained permission control, avoiding the `*` wildcard * Regularly back up world data --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://book.bsdcn.org/ask/flat/chapter-19-games-scientific-computing-and-professional-tools/di-19.2-jie-wo-de-shi-jie-minecraft-fu-wu-qi.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.