> DHT indexing already is possible and done in practice by passively observing get_peers queries. But that approach is inefficient, favoring indexers with lots

> DHT indexing already is possible and done in practice by passively observing get_peers queries. But that approach is inefficient, favoring indexers with lots of unique IP addresses at their disposal. It also incentivizes bad behavior such as spoofing node IDs and attempting to pollute other nodes' routing tables. Source: DHT Infohash Indexing < http://www.bittorrent.org/beps/bep_0051.html http://www.bittorrent.org/beps/bep_0051.html > Figurative speech aside, bittorrent.org acknowledges the need & the issue, and calls it bad, not "egregious". The paper[0] mentioned in the BEP 51 proposal describes more or less how magnetico works ("horizontal attack") and states in conclusion that > Through an extensive measurement study since December 2010, we have identified that both of these attacks are happening in the real network. We have analyzed their exact behavior through honeypots and have shown the scale of the on-going activities. We must stress that we have no concrete proof of actual malicious activities; our work only shows that the scale of attacks is large enough for this to be a concern. Repeating for the last time (as I feel this slowly creeps into a flame war): 1. As I have said, these technique is already in use. This means that the network is more resilient than you claim and the chances that a few hundred (or thousand, in future) magnetico instances will harm the network is near zero. I could answer in a more direct way if you did not use rain forest metaphor and addressed the issues you see more directly. 2. magnetico uses a similar but also a lot different technique. The horizontal (Sybil) attack requires the offending node to maintain its identity: "First, the attacker only has to answer two types of messages, `PING` and `FIND_NODE`; he can ignore every other message."[0] magneticod, in contrast, answers only `GET_PEERS` and `ANNOUNCE_PEER` queries, which are essential for the remote node to register itself as a peer downloading the torrent. magneticod will send hundreds of `FIND_NODE` queries per second[1] using forged node IDs, and that's all! According to the BitTorrent DHT protocol[2], "after 15 minutes of inactivity, a node becomes questionable." Hence, presumably, magneticod should be forgotten & removed from the routing table after it does not answer several `PING` queries. Consider that `FIND_NODE` queries that magnetico makes are targetting (at every single time) totally random nodes, so same set of nodes will not be targeted ever (statistically speaking). The problem is, BEP 51 is still a draft and AFAIK no clients in the wild implements it, so it's simply impractical to write a DHT search-engine depending on this particular behaviour. Once it becomes more widespread (hopefully together with BEP 42), magnetico will (and has to) drop its current technique and support the new and proper one. [0]: https://www.cl.cam.ac.uk/~lw525/publications/security.pdf https://www.cl.cam.ac.uk/~lw525/publications/security.pdf [1]: https://github.com/boramalper/magnetico/blob/257912a12f862d9f4ca3c5970df57f3a62d29c66/magneticod/magneticod/dht.py#L225 https://github.com/boramalper/magnetico/blob/257912a12f862d9... [2]: http://www.bittorrent.org/beps/bep_0005.html http://www.bittorrent.org/beps/bep_0005.html