JarsAuth
In the world of modded Minecraft, maintaining a level playing field is a constant challenge. Server administrators often struggle to ensure that every player is using the exact same modpack without any sneaky additions or removals. That is where JarsAuth steps in — a lightweight yet robust authentication mod designed to verify the integrity of a client's game files before allowing a connection to a server. Whether you run a competitive modded server or simply want to keep your community honest, JarsAuth provides a seamless solution.
What Is JarsAuth for Minecraft?
JarsAuth is a specialized Minecraft mod that acts as a gatekeeper for your server. Its core function is to calculate a unique hash based on the contents of specific folders in a player's Minecraft directory — typically the mods folder, but configurable to include others. This hash is then compared against a trusted hash stored on the server. If the hashes match, the player is allowed to join; if not, the connection is refused. This prevents players from adding unapproved mods, removing required ones, or tampering with configuration files that could give them an unfair advantage.
How JarsAuth Works
Understanding the mechanics behind JarsAuth helps you appreciate its efficiency. The mod scans all files within designated folders and computes a combined hash value. This process is multi-threaded, meaning it runs in the background without impacting your game's loading times or performance. Once the initial hash is calculated, JarsAuth continuously monitors the files for any changes every ten seconds. If a modification is detected, the hash is recalculated automatically, ensuring that the client's state is always up to date before attempting to connect to a server.
On the server side, the administrator sets the expected hash in the configuration file. When a player tries to join, the server compares the client's hash with the stored value. Only matching hashes are granted access. This simple yet effective mechanism stops players from using modified clients, whether they are trying to cheat or simply forgot to update their modpack.
Supported Minecraft Versions and Loaders
JarsAuth is compatible with both Forge and Fabric, the two most popular mod loaders in the Minecraft community. The mod has been updated to work with recent versions of the game, including 1.20.1 and 1.19.4, ensuring that server owners on the latest releases can take advantage of its protection. Legacy versions are also available for older modpacks, making it a versatile choice for any server setup.
How to Install JarsAuth
Installing JarsAuth is straightforward, but it requires careful setup on both the client and server sides. Follow these steps to get started:
Client Installation
- Download JarsAuth for your chosen mod loader (Forge or Fabric) from the official Modrinth page. Place the
.jarfile into your Minecraftmodsfolder. - Launch the game once to generate the configuration file. For Forge, it will appear at
.minecraft/config/jarsauth-client.toml; for Fabric, the file is.minecraft/config/jarsauth-client.txt. - Edit the configuration to specify which folders JarsAuth should monitor. By default, it checks the
modsfolder, but you can add others likeconfigorresourcepacksif your server requires it. - Restart the client, then join a singleplayer world and run the command
/jarsauth gethash. The calculated hash will be copied to your clipboard automatically.
Server Installation
- Place the same JarsAuth mod file into your server's
modsfolder and start the server to generate the server-side config. - Locate the server config file: for Forge, it is in
world/serverconfig/jarsauth-server.toml; for Fabric, it is inconfig/jarsauth-server.txt. - Paste the hash obtained from the client into the server config. For Forge servers, the change is applied automatically after a short delay; for Fabric, simply save the file.
- Restart the server if necessary, and players with matching hashes will now be able to connect.
If you are using the foxygame.net launcher, the process becomes even simpler. The launcher includes a built-in add-on catalog where you can find JarsAuth and install it with a single click, automatically handling version compatibility and configuration file placement. This eliminates manual file copying and reduces the chance of setup errors, making it an excellent choice for server administrators who want to streamline the modpack distribution process.
Configuring JarsAuth for Your Modpack
One of the strengths of JarsAuth is its flexibility. The client configuration file allows you to define exactly which folders are included in the hash calculation. This is particularly useful if your modpack uses custom scripts, resource packs, or configuration files that must remain consistent across all players. Simply add the relative paths to the jarsauth-client.toml or .txt file, and the mod will include them in the integrity check.
Be mindful of mods that dynamically alter files, such as I18nUpdateMod, which changes language files on every launch. These will cause the hash to change constantly, preventing players from connecting. Exclude such files or folders from the JarsAuth scan to avoid conflicts.
Why Choose JarsAuth for Your Server?
JarsAuth stands out for its simplicity and performance. Unlike some other authentication mods, it does not require complex network setups or external databases. The hash calculation is fast and non-intrusive, and the mod itself is lightweight. Server owners can easily integrate it into existing modpacks without worrying about performance hits. Additionally, the mod is open-source and actively maintained, with regular updates to support the latest Minecraft versions.
For those who prefer a hassle-free experience, the foxygame.net launcher offers a curated add-on catalog that includes JarsAuth, ensuring that you always have the correct version for your modpack and that updates are applied automatically when available. This integration saves time and keeps your server's authentication layer current without manual intervention.
Download JarsAuth and Get Started
Ready to secure your Minecraft server? You can download JarsAuth from Modrinth, where the latest versions for both Forge and Fabric are hosted. Remember to always use the most recent release to benefit from performance improvements and bug fixes. If you are managing a large modpack, consider distributing a pre-configured client with the correct hash already embedded to simplify the process for your players.
JarsAuth for Minecraft is an essential tool for any server owner who values fairness and consistency. By ensuring that every player is running the exact same files, you eliminate a major source of exploits and create a more enjoyable experience for your community. Whether you are running a small private server or a large public network, JarsAuth provides the peace of mind that your modpack is being used as intended.