Given the inaccuracies of the main documentation for RakNet, this is an attempt to provide a more accurate and complete description of the protocol.
| Type | Size (in bytes) | Range | Documentation |
|---|---|---|---|
| Byte | 1 | 0 - 255 | |
| Boolean | 1 | 0 - 1 | A one-byte value that represents true (0x1) or false (0x0). |
| Short | 2 | -32,678 - 32,677 | |
| Unsigned Short | 2 | 0 - 65,535 | |
| Unsigned Triad LE (UMediumLE) | 3 | 0 - 16,777,215 | This value is encoded as little endian. |
| Integer | 4 | -2,147,483,648 - 2,147,483,647 | A signed 32-bit integer. |
| Long | 8 | -2^63 to 2^63-1 | A signed 64-bit integer. |
In RakNet, a string is encoded as an unsigned short followed by the string bytes.
As an example, "Hello, World!" is encoded as the following:
| Encode Order | Example Value |
|---|---|
| Length (Unsigned Short) | 13 |
| Bytes | Hello, World! |
For IP addresses, encoding depends on the address family.
For IPv4 addresses, the address is encoded as the following:
| Encode Order | Type | Example Value | Documentation |
|---|---|---|---|
| Address Family | Byte | 4 | IPv4 |
| Bytes | Byte Array (4) | [192, 168, 0, 1] | Each part of the address is inverted using bitwise ~ and then masked with bitwise &. |
| Port | Unsigned Short | 19132 |
For IPv6 addresses, the address is encoded as the following:
| Encode Order | Type | Example Value | Documentation |
|---|---|---|---|
| Address Family | Byte | 6 | IPv6 |
| AF_INET6 | Short (Little Endian) | 10 | AF (Address Family), INET6 (IPv6) |
| Port | Short | 19132 | |
| Flow Info | Int | 0 | A part of the IPv6 protocol. 0 works fine as a value. |
| Address | Byte Array (16) | [0000, 0000, 0000, 0000, 0000, 0000, 0000, 0001] | |
| Scope ID | Int | 0 | A part of the IPv6 protocol. 0 works fine as a value. |
In RakNet, Magic, also known as OFFLINE_MESSAGE_DATA_ID in the original source, is a set of 16 bytes that is
used as a way to distinguish between offline messages and the rest of the protocol.
The hex bytes for Magic are:
0x00,0xFF,0xFF,0x00,0xFE,0xFE,0xFE,0xFE,0xFD,0xFD,0xFD,0xFD,0x12,0x34,0x56,0x78
The following is a list of all the packet types in the protocol.
These are the packets that are sent to/from the server when the client has not established a connection with the server.
This packet is sent to the server as a way to request information about the server.
| Field Name | Field Type | Documentation |
|---|---|---|
| Timestamp | Long | The current timestamp (in milliseconds) |
| Magic | Magic | See above in "Data Types" for more about this type |
| Client GUID | Long | A unique identifier sent by the client |
This packet is sent to the client as a way to respond to the Unconnected Ping.
| Field Name | Field Type | Documentation |
|---|---|---|
| Timestamp | Long | The timestamp from the UnconnectedPing sent by the client. |
| Server GUID | Long | A unique identifier sent by the server |
| Magic | Magic | See above in "Data Types" for more about this type |
| Server Name | String | In Bedrock Edition, this is used as a way to display the MOTD. |
In Bedrock Edition, the format for the server name is made up of the fields down below. Each
field is separated by the ; character.
| Name | Type | Documentation |
|---|---|---|
| Header | String | MCPE (for Bedrock Edition) or MCEE (for Education Edition) |
| MOTD | String | The main message seen by the client |
| Protocol Version | Int | The game protocol version (e.g., 475) |
| Game Version | String | The game version (e.g., 1.18.0) |
| Player Count | Int | The number of players currently online |
| Max Player Count | Int | The maximum amount of players that can be on the server |
| Server GUID | Long | The unique identifier sent by the server |
| Sub-MOTD | String | The secondary line (not seen by the client). Length must be > 0 |
| Game-mode | String | Creative, Survival, Adventure, etc. |
| Game-mode (Numeric) | Int | The only valid values for this are: 0, 1 |
| Port (IPv4) | Int | The port used by the server when connecting through IPv4 |
| Port (IPv6) | Int | The port used by the server when connecting through IPv6 |
This is the initial packet sent when the client wants to establish a connection with the server.
| Field Name | Field Type | Documentation |
|---|---|---|
| Magic | Magic | See above in "Data Types" for more about this type |
| Protocol Version | Byte | The current RakNet version (10 for Bedrock Edition) |
| Maximum Transfer Units (MTU) | Zero padding | The MTU size for the client consists of the entire buffer, but the padding is used as a way to get it to that value |
This packet is sent in response to the OpenConnectionRequest1 packet.
| Field Name | Field Type | Documentation |
|---|---|---|
| Magic | Magic | See above in "Data Types" for more about this type |
| Server GUID | Long | The unique identifier sent by the server |
| Use Security | Boolean | If using for Bedrock Edition, this field must be set to false |
| MTU Size | Short | The MTU size from OpenConnectionRequest1 + 20 bytes (IP header) + 8 bytes (UDP header) |
This is the second packet sent when the client wants to establish a connection with the server.
| Field Name | Field Type | Documentation |
|---|---|---|
| Magic | Magic | See above in "Data Types" for more about this type |
| Server Address | Address | The IP address of the server |
| MTU Size | Short | The finalized MTU size sent by the client |
| Client GUID | Long | The unique identifier sent by the client |
This packet is sent in response to the OpenConnectionRequest2 packet.
| Field Name | Field Type | Documentation |
|---|---|---|
| Magic | Magic | See above in "Data Types" for more about this type |
| Server GUID | Long | The unique identifier sent by the server |
| Client Address | Address | The IP address of the client connecting |
| MTU Size | Short | The final size of the MTU |
| Encryption Enabled | Boolean | Whether or not encryption will be used |
This packet is sent when the client is attempting to connect to a server that is running on a different RakNet version.
| Field Name | Field Type | Documentation |
|---|---|---|
| Protocol Version | Byte | The protocol version of the server |
| Magic | Magic | See above in "Data Types" for more about this type |
| Server GUID | Long | The unique identifier sent by the server |
In the RakNet protocol, all connected packets are contained inside a container format called a Datagram.
This packet is usually sent by the client to the server, but can also be sent by the server to the client.