Game Tracker

The Game Tracker is a central, master server that holds a list of all current multiplayer servers.

Method of operation
Upon starting a server, the server itself contacts the game tracker and sends a short packet. The game tracker detects what IP and port this packet is coming from, marks it as a server, and adds it to the list of currently running servers. When someone at the multiplayer Join Game screen queries the tracker, they also send a short packet requesting a list of servers. The tracker responds with a packet, or in some cases, multiple packets, containing a list of server IPs and ports. There is one byte for each octet of the IP, and two for the port, resulting in a total of 6 bytes per server. There is minimal overhead per reply (under 20 bytes). This is followed by a disconnect "handshake" by the server, and the connection is closed.

Game servers stay on the tracker by periodically sending a "PING" to the tracker (which replies with a resounding PONG). Due to the fact that the tracker will wait for a short time to pass until it removes a "dead" server (one that hasn't PINGed), the client must send these packets every one to three minutes.

Servers are removed from the tracker by either of two ways: Closing the server or not sending a PING. Closing the server will send a server removal request packet to the tracker. Just like when a server contacts the tracker to be added to the list, the tracker reads the source IP and port of this packet and removes that server from its list. The second way, not sending a PING, commonly occurs when a server crashes. Since the server is no longer running, it doesn't send any PINGs to the tracker, which will remove that server after a period of several minutes without pings.

The game tracker does not initiate any connections to clients/servers at any time. All connections are initiated by clients/servers.

What the tracker knows
The Red Faction game tracker protocol is very simple. The tracker software itself only knows the IP and port of each server. Server name, map name, and so on are retrieved from each server individually by the game client.

Tracker lag?
It is  not possible for the game tracker to make gameplay laggy.