Connection Packet Fixer

Connection Packet Fixer relaxes the packet size limits and timeouts that govern how a NeoForge connection handles large or slow traffic. Login compression, chunk and NBT packet limits are raised, and the keepalive timeout during login is extended, so servers and clients with heavy payloads or slow links are less likely to drop out with packet errors or timeouts.

The mod also addresses cleanup problems after a connection ends. A slow disconnect is bounded in time, so closed channels no longer hang indefinitely, and repeated malformed traffic sent before login is blocked. Client disconnects caused by signed chat verification failures are suppressed, and packet decode exceptions and payload issues caused by the same limits are reduced.

The mod is published for NeoForge only, for 1.21.1, with the 1.0.0 file dated 2026-06-03. A server running it needs every connecting player to have it too. The code is open source under the MIT License, and the source code and issue tracker are public.