Allow or block TNT duping on Paper

Paper blocks a handful of long-standing Minecraft exploits by default, including piston-based TNT duplication. If you run a technical or vanilla-style server where players expect those machines to work, you can allow them. If players are abusing them, you can check they are still blocked. Both are one line in a Paper config file.

Checked against Paper 26.3 and the Paper configuration reference, October 2026.

The settings

All of these live in config/paper-global.yml under unsupported-settings, and every one of them defaults to false, meaning the exploit is blocked.

Pick only what you need. For TNT duplication that is allow-piston-duplication. If players want sand duplicators as well, that needs allow-unsafe-end-portal-teleportation.

Change a setting

1. Open File Manager and go into the config folder.

2. Select paper-global.yml and click Edit.

3. Find the unsupported-settings: section and change the value you want. The key sits indented under the section name:

   unsupported-settings:
     allow-piston-duplication: true

4. Click Save.

5. Click Restart on the Console tab.

To block the exploit again, set the value back to false and restart. If the file stops loading after an edit, an indent is usually the cause. Find and fix YAML and JSON config errors shows how to spot it.

TNT behaviour you can adjust per world

Two TNT settings live in the world configuration instead, in config/paper-world-defaults.yml under fixes:

• prevent-tnt-from-moving-in-water (default false) stops primed TNT being pushed along by flowing water.
• tnt-entity-height-nerf (default disabled) sets the height at which primed TNT is removed.

Values in paper-world-defaults.yml apply to every world that does not override them. To change one world only, Paper reads overrides from a paper-world.yml inside that world's folder, at world/dimensions/<namespace>/<key>/paper-world.yml. With the default World folder name, the main Overworld is world/dimensions/minecraft/overworld/.

Which servers this covers

These files belong to Paper. Purpur and Folia are built on Paper, and neither changes the five options in the table above in its own patches, so the same file and keys apply to them. Check your software in JAR Manager. Edit bukkit.yml, spigot.yml and Paper config covers the other config files, and Stop TNT and creeper explosions covers explosion damage.

If the setting seems to do nothing

• You did not restart. Press Restart after you save.
• There is no config folder or paper-global.yml. Paper's configuration reference places paper-global.yml in the config folder. Check Server software in JAR Manager to see whether the server runs Paper.