Hotline Tracker Protocol

Connect to Tracker

Open a TCP connection to a Hotline Tracker. The default port number for a tracker is 5498.

Once a TCP connection has been established, the client sends a handshake packet.

The packet includes:

Field	Bytes
Magic Number	4	Server expects this field to be set to `0x4854524B` (`'HTRK'`).
Version	2	`0x0001` for old protocol (no tracker auth fields) or `0x0002` for new protocol.

If you specify 0x02 for the Version field, then you can include the following fields in the packet.

Field	Bytes
Login Size	1	Optional The length in bytes of the following login string.
Login String	~	Optional The user's login for this tracker.
Password Size	1	Optional The length in bytes of the following password string.
Password String	~	Optional The user's password for this tracker.

The server replies with the following:

Field	Bytes
Magic Number	4	The server replies with the same magic number `0x4854524B` (`'HTRK'`).
Version	2	The server's protocol version either `0x0001` or `0x0002`.
Message Type	2	The type of message the server is sending, which should be `0x0001`.
Message Size	2	The size of the expected remaining data.
Server Count	2	The number of servers specified in this message.
Server Count	2	A repeat of the previous field.
Server List	~	The list of server records.

Iterate through the remaining data up to the number of server's specified. Each server record consists of these fields:

Field	Bytes
Server IP Address	4	The IP address of the Hotline server.
Server Port Number	2	The port number of the Hotline server.
Number of Users	2	The number of users connected to this Hotline server right now.
Unused	2	This field is unused.
Name Size	1	The byte size of the Hotline server's name.
Name	~	The name of the Hotline server.
Description Size	1	The byte size of the Hotline server's description.
Description	~	The description of the Hotline server.

Once you have downloaded the server listening, you can then close the connection as no further data will be sent.