Packet Shield

Fixes these problems:

• Outgoing packets that exceed 8,388,608 bytes or have lengths over 8 bytes/wider than 21 bits are blocked

• Payloads larger than 1,048,576 bytes or 32,767 bytes are filtered

• Compressed packets exceeding 2,097,152 bytes are rejected

• Attempts to read NBT tags larger than 2,097,152 bytes are stopped

• Chunk packets trying to allocate excessive memory on read are discarded

• VarInt and VarLong values that exceed protocol limits are dropped

• Connection timeouts caused by malformed or oversized packets are prevented

• Player movements over 10 blocks per tick are blocked

• Vertical jumps higher than 5 blocks are restricted

• Extreme rotations (pitch beyond ±90° or yaw beyond safe per-tick limits) are filtered

• Interaction spam (more than 10 hand swings or block actions per second) is prevented

PacketShield works at the Netty level to intercept and validate outgoing packets, automatically filtering unsafe data before it reaches the server. Fully automatic, no settings required.

For a normal player experiencing typical client-side errors on vanilla or lightly-modded servers, PacketShield could reduce self-inflicted kicks by roughly 80–95%.