Authen
Running an offline-mode Minecraft server opens the door to anyone who knows the IP — and without proper authentication, that can mean griefers, impersonation, and chaos. Authen is a lightweight, no-nonsense plugin that brings real account protection to offline servers, VPN networks, and Radmin/Hamachi groups. It requires zero client mods, works out of the box, and keeps your community safe with password hashing that even a database leak can't crack.
Why Your Offline Server Needs Authen
In offline mode, Minecraft skips Mojang's session checks. That means any username can join, and without a plugin, there's nothing stopping someone from logging in as your admin. Authen solves this by forcing every player to register a password the first time they connect. Until they log in, they're completely locked down — no movement, no chat, no block breaking, no inventory access. It's the simplest way to turn an open door into a guarded gate.
Key Features
Password Authentication
Players use /register <password> <password> to create an account and /login <password> to access the server. The plugin supports configurable login timeouts, maximum failed attempts, and large center-screen title prompts that remind players to authenticate. You can also toggle blindness or teleport unauthenticated users to spawn, making it impossible to wander around before logging in.
IP Auto-Login for VPN Groups
Designed with Radmin and Hamachi networks in mind, Authen remembers each account's trusted IPs. After a successful password login, your IP is saved, and next time you connect you're logged in automatically — no password needed. Every player keeps their own personal IP, so there's no risk of cross-login. If a shared IP (like a NAT or mobile network) becomes trusted by multiple accounts, the plugin automatically disables auto-login for that IP and requires a password, closing a common account-takeover loophole.
Anti-Bot and Validation
Authen includes several layers of protection against automated attacks. You can set a maximum number of accounts per IP, enforce a join cooldown between connections, and define strict name and password policies. Invalid usernames, banned words, and short passwords are all rejected before an account is even created.
How to Install Authen
Getting started takes less than a minute. The plugin is built for Paper, Spigot, Purpur, and any compatible fork running Minecraft 1.21+ (tested up to 1.26.x) with Java 21 or newer. Here's the process:
- Download the Authen .jar file from its official Modrinth page.
- Place the .jar into your server's
plugins/folder. - Restart the server — Authen generates a default
config.ymlautomatically. - Optionally, tweak the configuration to match your community's needs.
If you're using the foxygame.net launcher, you can install Authen with a single click from its built-in add-on catalog, ensuring you always get the latest compatible version without hunting for downloads. Once the plugin is loaded, every new player will be greeted with a registration prompt, and your server is instantly protected.
Commands and Permissions
Authen keeps things simple for players while giving admins full control. Here are the main commands:
- /register <pass> <pass> (alias /reg) — Create a new account.
- /login <pass> (alias /l) — Log into your existing account.
- /changepassword <old> <new> (aliases /changepass, /passwd) — Update your password.
- /logout — End your current session.
- /authen — Admin command (requires
authen.adminpermission) for managing the plugin in-game.
Every message is fully customizable with MiniMessage formatting, so you can translate prompts, change colors, or add your server's personality.
Security You Can Trust
Under the hood, Authen never stores passwords in plain text. Instead, it uses PBKDF2-HMAC-SHA256 with 120,000 iterations and a unique random salt per password. The resulting hash is compared in constant time, making timing attacks irrelevant. Even if someone gains access to the plugin's data file, the original password cannot be recovered. This is the same battle-tested approach used by major platforms, scaled perfectly for a Minecraft server.
All protections are individually toggleable — you can disable movement blocking but keep chat locked, or turn off blindness while still preventing block interactions. The config file is well-commented, and the plugin uses flat-file storage, so there's no need for an external database.
Conclusion
Authen strips away the complexity of server authentication and delivers exactly what an offline community needs: secure password logins, smart IP auto-login for trusted networks, and robust anti-bot measures. It's a drop-in solution that respects both player convenience and admin control. Whether you're hosting a small private server for friends or a larger VPN-based network, Authen gives you peace of mind without ever touching the client. Download Authen today and turn your offline world into a safe, invite-only experience.
--- **Update Oct 3, 2026:** Added 1 file for version 26.2, 26.1.2, 26.1.1, 26.1, 1.21.9, 1.21.8, 1.21.7, 1.21.6, 1.21.5, 1.21.4, 1.21.3, 1.21.2, 1.21.11, 1.21.10, 1.21.1, 1.21.