How to Protect Your Base From Nether Portal Spread

Immediate Protection

The fastest way to shield a build is the four-coal-block trick: place four coal blocks within the portal's spread radius and the transformation stops for that portal. Do this for every portal near your base — one set per portal.

1. Walk the perimeter of your base and identify any portal whose radius overlaps it.

2. For each, place four coal blocks inside its radius, ideally on the side facing your build.

3. Verify the spread has halted before you log off.

Long-Term Planning

If you would rather not litter coal blocks everywhere, edit the config to shrink the spread radius so portals cannot reach your structures. A small radius means even a portal that spawns close by will only convert a thin ring of terrain.

Other habits that help:

• Build on terrain you do not mind losing, or surround the base with a buffer of blocks the mod does not convert.
• Keep an eye on the notifications the mod sends when a new portal is detected, so you can react before spread reaches anything valuable.
• Remember that portals are detected both when created and when a player travels from the Nether to the Overworld, so a return trip can trigger a fresh spread event.

Combining a small radius with coal blocks on the few portals that matter gives you the most control.