Nether Portal Spread

Nether Portal Spread

🔮 Spreads (nether) blocks to the overworld around nether portals in a configurable radius.

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665.9K Downloads
fabricforgeneoforgequiltadventuregame-mechanicsworldgen
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About this Mod

A Serilum Mod. Made with love. Lots of active mods for Fabric, Forge and Neo!

CurseForge Modrinth Patreon YouTube

About the mod

Nether portals spread (nether) blocks to the overworld around the portal in a configurable radius. By default you can stop the spread by placing four coal blocks within the portal's radius. This can however be changed in the config. Players around the portal will receive a message when the spread effect begins and when it is prevented.

The mod saves all portal locations to '../world-folder/data/netherportalspread/portals/'. A new portal is detected when it's created or when a player goes from the nether to the overworld. So for old worlds you'll have to go through it and back once to start the spread effect, or re-fire the portal. This makes it a lot more efficient than checking every block in the world for a portal.


Version 4.4 and above is compatible with the Immersive Portals mod.



Dependencies

Requires Collective
Included in The Vanilla ExperienceIncluded in Serilum's RPG Bundle
Environment: Server



Configurable

Configuration guide

   All available config options:

Show Spoiler

sendMessageOnPortalCreation  default true
When enabled, sends a message to players around the portal that the nether is spreading and that you can stop the spread with 'preventSpreadBlockAmountNeeded' of the 'preventSpreadBlockString' block.

messageOnPortalCreation  default "You feel a corrupt energy coming from the portal. The nether will slowly spread into the overworld unless %preventSpreadBlockAmountNeeded% %preventSpreadBlockString% are placed within a %portalSpreadRadius% block radius around the portal."
The message sent on portal creation.

sendMessageOnPreventSpreadBlocksFound  default true
When enabled, sends a message to players around the portal that the nether spread has stopped when the portal detects new 'preventSpreadBlockString' blocks.

messageOnPreventSpreadBlocksFound  default "With enough %preventSpreadBlockString% placed, you feel the corrupted energy fade."
The message sent on preventspread blocks found.

sendMessageOnPortalBroken  default true
When enabled, sends a message to players when a portal is broken.

messageOnPortalBroken  default "With the nether portal broken, the corrupted energy is no longer able to enter the overworld."
The message sent when a portal is broken.

prefixPortalCoordsInMessage  default true
When enabled, shows the portal coordinates in portal messages.

portalSpreadRadius  default 15, min 1, max 100
The radius around the portal to which the nether blocks can spread.

spreadDelayTicks   default 40, min 1, max 72000
 The delay in ticks in between the spread around the nether portal. 20 ticks = 1 second.

instantConvertAmount  default 50, min 0, max 1000
The amount of blocks that are instantly converted to a nether block around a portal when it is detected. If there are existing nether blocks within the radius, their count is subtracted from this number.

preventSpreadWithBlock  default true
When enabled, blocks the spread effect when there are n (defined) prevent-spread-blocks (defined) within the radius.

preventSpreadBlockAmountNeeded  default 4
The amount of prevent-spread-blocks (defined) needed within the radius of the nether portal to prevent spread.

preventSpreadBlockString  default "minecraft:coal_block"
The block which prevents the nether portal from spreading. By default a coal block (minecraft:coal_block is the namespace ID).



By default, the mod will send a message to players around the portal when:
A portal is created, and the spread starts:


Portal spread is stopped with the preventspread blocks (defined in config):


The message when a portal is broken:


Configurable spread blocks
You can define which blocks should spread to what and the chance of it happening in the "spreadsettings.txt" file located in "./config/netherportalspread/". By default it contains the following:

stone; [netherrack>10 + magma_block>2 + nether_quartz_ore>1],
grass_block; [netherrack>1],
dirt; [netherrack>1],
sand; [soul_sand>1],
gravel; [soul_sand>1],
stone_bricks; [nether_bricks>2 + red_nether_bricks>1],
sea_lantern; [glowstone>1],
farmland; [soul_sand>1],
wheat; [nether_wart>1]


The mod automatically adds "minecraft:" in front of the name values if it contains no ":" (colon).
The format is: FROMBLOCK; [TOBLOCK>WEIGHT (+ TOBLOCK>WEIGHT + TOBLOCK>WEIGHT) ]
The weight is automatically converted to chance values. This is calculated by: (1/total_weight)*weight.
So the default config file means:

Convert stone into 76.92% netherrack. 15.38% magma blocks and 7.7% quartz ore.
Convert grass blocks into 100% netherrack.
Convert dirt into 100% netherrack.
Convert sand into 100% soul sand.
Convert gravel into 100% soul sand.
Convert stone bricks into 66.67% nether bricks and 33.3% red nether bricks.
Convert sea lanterns into 100% glowstone.
Convert farmland into 100% soul sand.
Convert wheat into 100% netherwart.

 

Minecraft 1.16 and up has a different default config, using the new blocks:

Show Spoiler

stone; [netherrack>10 + magma_block>2 + nether_quartz_ore>1],
grass; [nether_sprouts>1],
cobblestone; [blackstone>1],
grass_block; [crimson_nylium>1],
dirt; [netherrack>1],
coarse_dirt; [soul_soil>1],
sand; [soul_sand>1 + soul_soil>1],
red_sand; [soul_soil>1 + soul_sand>1],
sandstone; [blackstone>1],
cut_sandstone; [polished_blackstone>1],
chiseled_sandstone; [chiseled_polished_blackstone>1],
smooth_sandstone; [basalt>1],
smooth_red_sandstone; [basalt>1],
gravel; [soul_soil>1],
stone_bricks; [nether_bricks>2 + red_nether_bricks>1],
sea_lantern; [glowstone>1],
farmland; [soul_sand>1],
wheat; [nether_wart>1],
gold_ore; [nether_gold_ore>1],
fern; [nether_sprouts>1],
oak_leaves; [nether_wart_block>1],
spruce_leaves; [nether_wart_block>1],
birch_leaves; [warped_wart_block>1],
jungle_leaves; [warped_wart_block>1],
acacia_leaves; [nether_wart_block>1],
dark_oak_leaves; [warped_wart_block>1],
oak_log; [crimson_stem>1],
spruce_log; [crimson_stem>1],
birch_log; [warped_stem>1],
jungle_log; [warped_stem>1],
acacia_log; [crimson_stem>1],
dark_oak_log; [warped_stem>1],



Description

You can also spread blocks from other mods:
Example with Soulstone from Mystical Agriculture:

For modded blocks the format is [MODID:Blockname>weight]



Showcase

(with old spread settings)

1
2
3
4
5



Notes and links

You may freely use this mod in any modpack, as long as the download remains hosted within the CurseForge or Modrinth ecosystem.

Serilum.com contains an overview and more information on all mods available.

For issues, ideas, suggestions or anything else there is the Github repo. Thanks!


Available Versions

[Fabric/Forge/Neo] 26.2.0-8.4release
MC 26.2fabric, forge, neoforge, quilt
June 18, 2026
[Fabric/Forge/Neo] 26.1.2-8.4release
MC 26.1.2fabric, forge, neoforge, quilt
April 9, 2026
[Fabric/Forge/Neo] 26.1.1-8.4release
MC 26.1.1fabric, forge, neoforge, quilt
April 2, 2026
[Fabric/Forge/Neo] 26.1.0-8.4release
MC 26.1fabric, forge, neoforge, quilt
March 25, 2026
[Fabric/Forge/Neo] 1.21.11-8.4release
MC 1.21.11fabric, forge, neoforge, quilt
December 11, 2025

How to Install Nether Portal Spread on Your Server

1

Order Server

Order a Minecraft Java server with at least 4 GB RAM (6 GB recommended).

2

Set fabric Loader

In the panel under "Egg", select the fabric loader and matching Minecraft version (26.2).

3

Install Mod

Open the mod browser in the dashboard and search for "Nether Portal Spread". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.

Compatibility

Mod Loaders

fabricforgeneoforgequilt

Minecraft Versions

26.2, 26.1.2, 26.1.1 (+25 more)

Server-side

Required

Recommended RAM

6 GB(min. 4 GB)

Frequently Asked Questions

Nether Portal Spread server crashes on startup – what to do?

Most common cause: wrong fabric version or insufficient RAM. Check the server log (latest.log) for "OutOfMemoryError" or "Mixin" errors. With Mado Hosting: ensure at least 4 GB RAM is allocated and the loader matches the mod version (26.2). You can switch loaders with one click in the panel.

Is Nether Portal Spread compatible with fabric and forge and neoforge and quilt?

Nether Portal Spread officially supports fabric, forge, neoforge, quilt for Minecraft 26.2, 26.1.2, 26.1.1. Note: Forge and Fabric mods are NOT cross-compatible – pick one loader and stick with it. The Mado dashboard automatically detects incompatible loader combinations.

Server lagging with Nether Portal Spread – how to optimize performance?

Recommended RAM: 6 GB (per 5 players). Use /spark profiler to check if Nether Portal Spread consumes the most tick time. Common fixes: reduce server view-distance to 8-10, install "performant" or "starlight" as supplementary mods on Forge. With Mado Hosting, your server runs on NVMe SSDs with dedicated CPU cores for minimal latency.

Rent Modded Server

Install Nether Portal Spread with just one click on your server.

Recommended RAM
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Minimum 4 GB | per 5 players
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Details

License
LicenseRef-All-Rights-Reserved
Server-side
Required

Supported Versions

26.226.1.226.1.126.11.21.111.21.101.21.91.21.81.21.71.21.6+18 more