RakNet and MCPE

Minecraft Bedrock uses a protocol known as RakNet Unlike Minecraft Java edition, Bedrock uses UDP on the port 19132

You can find a list of Minecraft Bedrock server softwares here.

RakNet Notes

  • All strings are prefixed with an unsigned short depicting their length.
  • The offline message id will always be: 00ffff00fefefefefdfdfdfd12345678 (hex) - this series of bytes will be referred to as Magic
  • The offline message id is sent with unconnected messages such as unconnected pings and pongs.
  • The GUIDS used by RakNet are 8 bytes long.
  • The first byte is used to identify the type of message.

Data Types

TypeSizeRangeNotes
Byte10-255An unsigned integer
Long8-2^63 to 2^63-1Signed 64 bit integer
Magic1600ffff00fefefefefdfdfdfd12345678 - Will always be those bytes
Short2-32768 to 32767
Unsigned Short20 to 65535
StringN/AN/AA string prefixed by a short which depicts the length.
Boolean10-10x00 is False while 0x01 is True
Address71 byte for the ip version 4/6, 4 for the IP and 2 for the port
uint24le33-byte little-endian unsigned integer

Contents

Unconnected Pings

Minecraft Bedrock will send out a message to all listed servers (and the local netowrk) to check if any games are available and retrieve the MOTD from the game. These messages are known as unconnected pings and are structured in this format:

0x01 | client alive time in ms (unsigned long long) | magic | client GUID

Unconnected Pongs

After this message, the server will respond with something called an unconnected pong. The reason these messages are unconnected is because the client has not established a connection to the server. This is the format of an unconnected pong:

0xc1 | client alive time in ms (recorded from previous ping) | server GUID | string length | Edition (MCPE or MCEE for Education Edition);MOTD line 1;Protocol Version;Version Name;Player Count;Max Player Count;Server Unique ID;MOTD line 2;Game mode;Game mode (numeric);Port (IPv4);Port (IPv6);

Example:

MCPE;Dedicated Server;527;1.19.1;0;10;13253860892328930865;Bedrock level;Survival;1;19132;19133;

The client doesn't seem to use the gamemode or the numeric value for the gamemode.

Open Connection Request 1

The client sends this when attempting to join the server

0x05 | Magic | Protocol version (currently 10 or 0x0a) | RakNet Null Padding

The null padding seems to be used to discover the maximum packet size the network can handle.

The client will send this to the server with decreasing null padding until the server responds with a

Open Connection Reply 1

The server responds with this once the client attempts to join

0x06 | magic | server GUID | use encryption boolean (normally false) | RakNet Null Padding Size (Unsigned short, I use 1400)

This is the first half of the handshake between the client and the server.

Open Connection Request 2

The client responds with this after they recieve the open connection reply 1 packet.

0x07 | magic | server address | RakNet Null Padding Size | client GUID

Open Connection Reply 2

This is the last part of the handshake between the client and the server.

0x08 | magic | server GUID | client address | Null Padding Size | use encryption

Sources

RakNet DocumentationGame Packets

This page is a WIP, feel free to contribute as it is still being worked on.

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