Trackerpalvelinta

Trackerpalvelinta, or tracker server, is a server in a peer-to-peer file-sharing network that coordinates peers participating in a torrent swarm. It does not host the shared content; instead it helps peers discover other peers and exchange metadata needed to download the files.

In BitTorrent-style systems, peers periodically send announce requests to the tracker with information such as info-hash, peer-id, IP address, port, and statistics (uploaded, downloaded, left). The tracker responds with an interval, a list of peers, and status flags. The announced peers use this information to establish direct connections and exchange pieces.

Trackers come in centralized and distributed forms. A centralized tracker is a single server or cluster that answers announce requests for many torrents. Trackerless approaches rely on distributed hash tables (DHT) and peer exchange (PEX) to locate peers without a central tracker.

Public trackers allow anyone to participate; private trackers restrict access and often enforce ratios and login authentication. Trackers offer /announce endpoints and optionally /scrape endpoints for statistics such as complete, incomplete, and downloaded counts.

With the rise of magnet links and DHT, reliance on traditional trackers has decreased, but trackers remain common for many torrents and for maintaining swarm health, especially private trackers that require controlled entry.

Privacy and reliability: Trackers log IP addresses and user activity, which raises privacy and surveillance concerns. A tracker outage can isolate a swarm, which has driven the adoption of trackerless methods and distributed tracking.