1. Introduction

Short version: you want to completely disable the Nether so players cannot enter it using portals or any other method.
This works on Vanilla, Spigot, Paper, Purpur and on all versions from 1.8 up to the newest releases.
Below are the exact, reliable steps. If done correctly, it always works.

2. Requirements Before You Start

• Access to your server files (via File Manager or FTP).
• Permission to edit server.properties.
• Ability to stop and start the server from the control panel.
• Knowledge of your main world name (default: world).

3. Stop the Server

This step is mandatory.

From your hosting panel:

1. Click Stop.
2. Wait until the server status shows Offline.

Never edit world or config files while the server is running.

4. Open server.properties

Access your server files using one of these methods:

• File Manager → open the main server directory.
• FTP (FileZilla) → connect using your FTP credentials and open the root directory.

Find and open the file:

server.properties

5. Disable the Nether in Configuration

In server.properties, locate this line:

allow-nether=true

Change it to:

allow-nether=false

Save the file.

6. Remove the Existing Nether World (Optional but Recommended)

To ensure the Nether is fully disabled and cannot load at all, delete the Nether world folder.

If your main world is default:

world_nether

If you use a custom world name (e.g. customworld):

customworld_nether

This does not affect the main world or player inventories.

7. Start the Server

Return to your control panel and click: Start

If everything is correct:

• Nether portals will no longer work.
• The Nether world will no longer load.
• Players will be completely unable to enter the Nether.

8. Disabling the Nether Only for Players (Plugin Method - Optional)

If you want the Nether to remain technically active but inaccessible to players:

You can use:

• WorldGuard
• Multiverse
• Essentials-based portal blocking

Example (WorldGuard approach):

• Select a region around the portal.
• Block portal usage permissions inside that region.

This method is useful if only admins should access the Nether.

9. Common Problems (and How to Fix Them)

Portal still works

• The server was not fully restarted.
• There is a typo in allow-nether=false.
• The file was not saved properly.

Nether keeps generating again

• You deleted the wrong folder.
• Your main world has a custom name (level-name= in server.properties).

I use Multiverse and the Nether still exists

Remove the Nether world from Multiverse:

/mv remove world_nether

(Only if it was previously imported into Multiverse.)

10. Admin Notes

• Disabling the Nether does not delete player inventories.
• You can re-enable it at any time by setting:

allow-nether=true

• On public servers, it is recommended to:
• Inform players in advance.
• Remove flint & steel and obsidian from shops/creative.
• Secure existing portal locations.