XXL Packets Mod FAQ

Yes. The mod must be installed on the server and on every client that connects, since the client is the side that rejects oversized packets. If a client joins without it, they can still get kicked even though the server has it.

Check your log for the packet size limit being raised, or try joining a server that previously kicked you with a 'packet too large' error. If the kick stops and you connect normally, the mod is working.

Yes, that is exactly what it is for. It raises the packet size limit so recipe-heavy modpacks and large datapacks no longer exceed the vanilla cap and kick the client.

Both. The server sends the oversized packets, but the client is what enforces the limit and disconnects, so each connecting client needs the mod as well.

Generally you should not stack it with other mods that change the same packet limit, as they may conflict. Use only one mod that raises the packet size cap.

It only changes the maximum allowed packet size, so it does not add ongoing overhead. Very large packets can still use more memory when they are sent, but the mod itself is lightweight.

The most common cause is that the connecting clients do not have the mod installed. Every client that joins must have XXL Packets, not just the server.

Yes, it is a fork of XL Packets that raises the limit much higher. You should use XXL Packets instead of XL Packets, not both together.

The mod is available for the major mod loaders, but you must match the version to your loader and game version. Check the file you downloaded is for the loader you actually run.

It removes the packet-size kick, but it does not fix other connection problems like missing mods or version mismatches. You still need matching mods and versions to join.