How to Disable Online Mode (Offline Mode) on Your Minecraft Server

In Minecraft, Online Mode is a security feature that verifies connecting players against Mojang/Microsoft authentication servers. When online-mode=true, Minecraft ensures that every player who joins has a legitimate, paid Minecraft account.

Disabling online mode (online-mode=false) switches the server into Offline Mode (commonly referred to as allowing "cracked" or non-premium clients). While this is a common requirement for proxy networks (like BungeeCord or Velocity), running a standalone offline server introduces major security vulnerabilities.

This guide covers the security risks, how to disable online mode, and how to protect your server if you choose to do so.

⚠️ Severe Security Risks of Offline Mode

Before disabling online mode, you must understand the serious security consequences:

1. Account Impersonation & OP Theft: Without Mojang authentication, anyone can log into your server using ANY username they choose. If a malicious player types your admin or OP username, they will automatically join as an admin with full OP powers, without needing a password!

2. Loss of Official Skins: Players will no longer display their official Minecraft skins and will appear as default Steve or Alex skins unless you install a skin restoration plugin like SkinsRestorer.

3. UUID & Inventory Resets: Minecraft assigns player inventories and permissions based on UUIDs. Switching a world from online-mode=true to online-mode=false changes player UUIDs from Mojang-assigned IDs to offline-generated IDs. This can cause existing players to lose their inventories, ender chests, and claim permissions.

How to Disable Online Mode

If you are setting up a Proxy network or intend to run an authentication plugin, follow these steps to turn off online mode:

Log in to your Cubes Hosting Game Panel and Stop your server.
Open the File Manager on the left menu.
Locate the server.properties file in your root directory and open it.
Find the line:
```
online-mode=true
```
Change the value to false:
```
online-mode=false
```
Save the file and Start your server.

How to Secure an Offline Mode Server

If you run a standalone server with online-mode=false, you MUST install protective measures to prevent account theft.

1. Install an Authentication Plugin (Mandatory for Standalone Servers)

You must install a password authentication plugin so players are forced to register and log in with a password (/register <password> / /login <password>) upon joining.

AuthMeReloaded (Spigot/Paper)
nLogin (Modern Paper/Purpur)

2. For BungeeCord & Velocity Proxy Networks

If you disabled online mode on your backend sub-servers for a BungeeCord or Velocity network:

Keep online-mode=true on your proxy server (Bungee/Velocity). The proxy will authenticate official accounts before forwarding them to your sub-servers.
Enable BungeeGuard on your backend servers so players cannot bypass your proxy and join sub-servers directly with fake usernames.

Conclusion

Disabling online mode is required for proxy networks and offline communities, but it removes Mojang's native account verification. If you set online-mode=false, always protect your server with an authentication plugin like AuthMeReloaded or secure your proxy network with BungeeGuard!