Skip to content

Firewall

Filters sent/received packets

Fabric
Loaders
Fabric
Downloads on Modrinth
1.5K
Followers on Modrinth
5
versions
36
Updated
August 27, 2026Aug 27
Published
in 2025
Configuration screen · swipe

At a glance

Runs on Fabric
For Minecraft 1.21–1.21.11, 26.1.2–26.2
Works on either side — install it in the game, on the server, or both
Latest version — 1.5.0 from August 27, 2026
Requires Fabric API and oωo (owo-lib)
License MIT — free
Where it's needed
In gameoptionalOn serveroptional

Works both in the game and on the server — install where you need it

Game versions1.21–1.21.11, 26.1.2–26.2

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

Installation

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.

FAQ

How to install Firewall?

Install Fabric for your Minecraft version, download Firewall for the same version and loader, put the file into the mods folder and launch the game with the loader profile.

Which Minecraft versions does Firewall support?

Firewall has builds for Minecraft 1.21–1.21.11, 26.1.2–26.2.

Is Firewall needed on the server?

Works on either side — install it in the game, on the server, or both

License and source
MIT Licensefree to use and share with credit to the author
Original — Modrinth↗Files unchanged, verified with SHA-512Is this your mod? For rights holders

The site uses cookies: the necessary ones for sign-in and the theme, plus the Yandex Metrica and LiveInternet visit counters — they show us how the site is used. We have no advertising cookies. More