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LinuxAuthenticator

A Paper plugin that authenticates Minecraft players with Linux-related questions. Only true Linux users get in! 🐧

LinuxAuthenticator

A plugin for Minecraft servers based on Paper that authenticates players using Linux-related questions. Only real Linux users can access the server! 🐧

Features

Two authentication modes:
- CHOICE – players choose the correct answer from multiple options (click or chat)
- TEXT – players type the exact answer in chat
Customizable questions on various aspects of Linux
Timeout system to prevent players from stalling
Error limit – configurable number of mistakes before being kicked
Ban system – automatic ban after too many failed attempts
Mob protection – mobs ignore unauthenticated players
Once-per-session authentication – no need to re-authenticate on every reconnect
Admin commands to control the plugin
Permission system for skipping authentication
Supports Paper and Folia 1.21-1.21.7

Installation

Download the latest version of the plugin.
Place the JAR file in your server's plugins folder.
Restart the server.
Configure the plugin in plugins/LinuxAuthenticator/config.yml.

Configuration

Main Settings

settings:
  mode: "CHOICE" # Authentication mode: CHOICE or TEXT
  questions_count: 3
  timeout_seconds: 60
  max_errors: 3
  max_attempts: 3
  ban_duration_minutes: 15
  ban_command: "" # Optional external command to execute on ban
  auth_once_per_session: true

Messages

settings:
  messages:
    welcome: "§aWelcome to the server! §ePlease answer some Linux questions to log in:"
    correct_answer: "§aCorrect! Next question:"
    wrong_answer: "§cWrong! Try again."
    timeout: "§cTime's up! You have been kicked from the server."
    success: "§aCongratulations! You are now authenticated!"
    kick_message: "§cYou failed Linux authentication. Please try again later!"

Questions

The plugin uses a universal question system compatible with both modes:

In CHOICE mode, multiple answer options are shown.
In TEXT mode, only the exact answer is accepted.

A ready-to-use set of Linux-related questions is included, covering:

Package managers (pacman, apt, dnf, zypper, emerge, apk)
Core Linux commands (ls, find, chmod, ps, mkdir, rm, cp, mv, cat)
System files (/proc/modules, /proc/loadavg, /proc/cpuinfo, /proc/meminfo)

You can add your own questions in the config.

Commands

For Players

No special commands required

For Admins

/linuxauth reload – Reload the config
/linuxauth reset <player> – Reset a player's authentication status
/linuxauth unban <player> – Unban a player
/linuxauth info – Show plugin info
/linuxauth resetsession – Reset the authentication session (all players must re-authenticate)

Permissions

linuxauthenticator.admin – Access to admin commands (default: op)
linuxauthenticator.bypass – Skip authentication (default: op)
linuxauthenticator.answer – Can answer questions (default: true)

How It Works

When a player joins, authentication begins (if enabled).
The player is asked questions about Linux based on the selected mode.
In CHOICE mode, the player:
- Clicks an answer, or
- Types it in chat (number or text)
In TEXT mode, the player must type the exact answer.
Answer options are randomized each time.
Too many errors – player is kicked.
Too many attempts – player is banned for a set time.
Mob protection – mobs cannot attack unauthenticated players.
Correct answers – player gains access to the server.
One-time per session – no need to re-authenticate after every reconnect.

Adding Your Own Questions

Add your questions in the questions section:

questions:
  - question: "Your question here?"
    answer: "correct_answer"
    options:
      - "option_1"
      - "correct_answer"
      - "option_3"
      - "option_4"

Notes: