Firewall

Firewall

Filters sent/received packets

by
979 Downloads
fabricmanagementutility
Rent Server with this Mod

Screenshots

Configuration screen
Every change to the packets is logged

About this Mod

This is a Minecraft Fabric mod that allows you to configure what packets are sent/received.

Installation

  • Fabric API (required);
  • owo-lib (required);
  • Mod Menu (or some other mod to change the mod's config) (very much recommended).

Usage

The mod filters the sent/received packets, by default (default config) it does nothing.

⚠️ Note that since it directly rejects/filters the sent/received packets (as configured), it may break some mods or vanilla systems, especially if you filter the packet identifiers (the first option), changing the other options probably won't break the vanilla game. Configure carefully!

The entire mod is configured through the Mod Menu UI with helpful tooltips; note that each change to the packets (rejecting or filtering them) is logged to the console. Below is a short description of every option currently there:

Packet identifiers

Control which packet identifiers are allowed.

For a list of all of them see the Minecraft Wiki article on Java Edition packets, specifically resouce in the Packet ID field of any packet. Note that you need to prefix the id with minecraft: namespace, for example minecraft:custom_payload.

Custom payload identifiers

Control which custom payload packet (aka plugin message or channel) identifiers are allowed, sent by most of the mod/plugin loaders and some of mods/plugins.

You can select the setting Use from "Registered channel identifiers" option below to also apply the filters from the respective option.

For a list of some of the identifiers see the Minecraft Wiki article on plugin channels, or the respective mod/plugin documentation for the sent packets. Again, like the packet identifiers, don't forget the minecraft: or some other namespace.

The Respond to rejected received query requests should probably be enabled, as to not break the handshaking flow.

Registered channel identifiers

Control which channel identifiers in minecraft:register, minecraft:unregister (used by Bukkit, BungeeCord, Velocity and Fabric API) and c:register packets (used by FabricMC, NeoForged, PaperMC and SpongePowered team) are allowed.

You can select the setting Use from "Custom payload identifiers" option above to also apply the filters from the respective option.

You can deselect the Send/Receive empty channel lists options to not send/receive empty channel lists.

For a list of some of the identifiers, again, see the Minecraft Wiki article on plugin channels.

Identifiers of logged packets

What packets should be logged - regardless of if they're rejected or not. By default none are logged.

Identifiers of logged custom payloads

What custom payloads should be logged - regardless of if they're rejected or not. By default none are logged.

I have a problem/suggestion/translation

Please open an issue on GitHub.

Available Versions

1.5.0release
MC 1.21.11fabric
February 23, 2026
1.5.0release
MC 1.21.10fabric
February 23, 2026
1.5.0release
MC 1.21fabric
January 14, 2026
1.5.0release
MC 1.21.1fabric
January 14, 2026
1.5.0release
MC 1.21.2fabric
January 14, 2026

How to Install Firewall on Your Server

1

Order Server

Order a Minecraft Java server with at least 3 GB RAM (4 GB recommended).

2

Set fabric Loader

In the panel under "Egg", select the fabric loader and matching Minecraft version (1.21.11).

3

Install Mod

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

Compatibility

Mod Loaders

fabric

Minecraft Versions

1.21.11, 1.21.10, 1.21.9 (+9 more)

Server-side

~ Optional

Recommended RAM

4 GB(min. 3 GB)

Frequently Asked Questions

Firewall 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 3 GB RAM is allocated and the loader matches the mod version (1.21.11). You can switch loaders with one click in the panel.

Is Firewall compatible with fabric?

Firewall officially supports fabric for Minecraft 1.21.11, 1.21.10, 1.21.9. The Mado dashboard automatically detects incompatible loader combinations.

Server lagging with Firewall – how to optimize performance?

Recommended RAM: 4 GB (per 8 players). Use /spark profiler to check if Firewall 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 Firewall with just one click on your server.

Recommended RAM
4 GBab €8/mo
Min. 3 GB | +1 GB pro 8 Spieler
Create Server Now
1-Click Mod Install
NVMe SSD Storage
DDoS Protection included

Details

License
MIT License
Server-side
Optional

Supported Versions

1.21.111.21.101.21.91.21.81.21.71.21.61.21.51.21.41.21.31.21.2+2 more