Resurrecting a dead torrent tracker and finding 3M peers

Summary

So I was uh, downloading some linux isos, like usual. It was going slowly, so I opened up the Trackers tab in qBittorrent and saw the following: Most of the trackers were totally dead. Either the hosts were down or the domains weren’t being used. That got me thinking. What if I picked up one of these dead domains? How many clients would try to connect? What are trackers for, anyways? A tracker is a core component of the BitTorrent protocol. Trackers are the services that point you to other peers for the torrent. Without trackers, there would be no one to share the file with. Obviously this represents a major source of centralization in the torrent protocol. If your trackers aren’t maintained – or if they get forced offline by certain industry organizations – you’re out of luck. We have an alternative, called Mainline DHT, which performs a more decentralized lookup of peers based on infohash alone. DHT isn’t perfect, though. It relies on bootstrap nodes and is vulnerable to Sybil attacks. And in the example of my poorly-served torrent, DHT wasn’t surfacing any peers, regardless. Hosting a tracker Looking through the list of trackers marked “host not found”, I noticed udp://open.demonii.si:1337/announce was available. I bought the domain through Dynadot (one of the few .si domain registrars), then spun up a quick anonymous VPS. I mapped the domain to the VPS, then set up opentracker, the most widely used and robust torrent tracker software. Instructions for Ubuntu 24.04: sudo apt install gcc-14 g++-14 build-essential zlib1g-dev sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-14 14 sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-14 14 Follow the readme to compile, first the dependency libowfat (a GPL reimplementation of some of dan bernstein’s C libraries) and then opentracker itself. cvs -d :pserver:cvs@cvs.fefe.de:/cvs -z9 co libowfat cd libowfat make cd .. git clone git://erdgeist.org/opentracker cd opentracker make Finally, a quick...