Setting Up XXL Packets on a Server So All Clients Can Join

Server-Side Requirement

The mod must be installed on the server, but it is not enough on its own. Every client that connects also needs the mod installed locally, because the packet size limit is enforced on the receiving side. A vanilla client will still be kicked when the server sends a large packet.

Configuration Steps

1. Install the mod into the server's mods folder and restart the server.

2. Distribute the mod to all players who connect. If you run a modpack, include it in the pack so clients get it automatically.

3. Test with a client that has the mod. Join and confirm no oversized-packet disconnect occurs.

4. Test with a client that lacks the mod to confirm the failure mode, so you understand what players without it will see.

Managing Player Expectations

Announce to your players that the mod is required. Players joining without it will be disconnected during the initial data sync, often before they see the world. Provide clear instructions on where to get it and that it goes in the client mods folder.

Large Datapack Servers

If your server uses extensive datapacks or recipe-heavy mods, this mod is effectively mandatory for a smooth join experience. Without it, the recipe sync packet alone can exceed the vanilla limit and block all connections.