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23-493: OpenBitTorrent (commonly abbreviated OBT ) is an open BitTorrent tracker project for the BitTorrent protocol. OpenBitTorrent's initiative to provide a free, stable service with no ties to indexing sites or even hosting torrent files has been a public success and it has spawned several copies with almost identical services. OpenBitTorrent has been suspected of being a part of, or a side project of, The Pirate Bay , because it

46-604: A centralized tracker, PEX increases the speed, efficiency, and robustness of the BitTorrent protocol. Users wishing to obtain a copy of a file typically first download a torrent file that describes the file(s) to be shared, as well as the URLs of one or more central computers called trackers that maintain a list of peers currently sharing the file(s) described in the .torrent file. In the original BitTorrent design, peers then depended on this central tracker to find each other and maintain

69-491: A file communicate with the tracker periodically to negotiate faster file transfer with new peers, and provide network performance statistics; however, after the initial peer-to-peer file download is started, peer-to-peer communication can continue without the connection to a tracker. Modern BitTorrent clients may implement a distributed hash table and the peer exchange protocol to discover peers without trackers; however, trackers are still often included with torrents to improve

92-452: A group of peers to be added to the swarm and a group of peers to be removed. It was agreed between the Azureus and μTorrent developers that any clients which implement either of the mechanisms above try to obey the following limits when sending PEX messages: Some clients may choose to enforce these limits and drop connections from clients that ignore them. To create a PEX protocol providing

115-456: A software client on an end-user PC requests a file, and portions of the requested file residing on peer machines are sent to the client, and then reassembled into a full copy of the requested file. The "tracker" server keeps track of where file copies reside on peer machines, which ones are available at time of the client request, and helps coordinate efficient transmission and reassembly of the copied file. Clients that have already begun downloading

138-519: A tracker may store only a subset of the peers, but these are maximal subsets constrained only by DHT node load rather than by a single peer's view. Private torrents commonly disable the DHT, and for this case, PEX might be useful provided the peer obtains enough peers from the tracker. There are three incompatible PEX implementations (making distinct "networks" in swarm) Most BitTorrent clients use PEX to gather peers in addition to trackers and DHT. With

161-600: A tracker using a ".torrent" file, or else use a router computer called a bootstrap node to find a distributed hash table (DHT) which describes a swarm's list of peers. For most BitTorrent users, DHT and PEX will start to work automatically after the user launches a BitTorrent client and opens a .torrent file. A notable exception is "private torrents" which are not freely available; these will commonly disable DHT. Extensions to BitTorrent such as PEX are typically implemented using one of two common extension protocols, AZMP or LTEP. Both types of peer exchange send messages containing

184-460: A uniformly-distributed peer selection, one could form a small distributed hash table (DHT) local to a torrent. For each desired new peer one would look up a (uniformly) random key, and use the node responsible for the key as a new peer. This is conceptually simple but would require quite some overhead. For "trackerless" torrents, it is not clear if PEX provides any value since the mainline DHT can distribute load as necessary. Each DHT node acting as

207-458: A while in late 2018 and was unresponsive again in late 2019. In 2020, the website was redirecting to Opentracker , another torrent tracker. However a year later in January 2021, OpenBitTorrent came back online again with its own tracker and website. This website-related article is a stub . You can help Misplaced Pages by expanding it . BitTorrent tracker In peer-to-peer file sharing ,

230-442: Is an open source BitTorrent client with a built-in tracker support. BitTorious is an open source, commercially supported tracker with integrated web-based management portal. Peer exchange Peer exchange or PEX is a communications protocol that augments the BitTorrent file sharing protocol. It allows a group of users (or peers ) that are collaborating to share a given file to do so more swiftly and efficiently. In

253-408: Is connected to by asking them for the addresses of peers that they are connected to. This is faster and more efficient than relying solely on one tracker and reduces the processing load on the tracker. It also keeps swarms together when the tracker is down. Peer exchange cannot be used on its own to introduce a new peer to a swarm. To make initial contact with a swarm, each peer must either connect to

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276-427: Is distributed over BitTorrent using a "secure" tracker system. Trackers are the primary reason for a damaged BitTorrent "swarm". (Other reasons are mostly related to damaged or hacked clients uploading corrupt data.) The reliability of trackers has been improved through two main innovations in the BitTorrent protocol. Multi-tracker torrents contain multiple trackers in a single torrent file. This provides redundancy in

299-549: The Vuze client to reach a bigger swarm. Most BitTorrent clients also use Peer exchange (PeX) to gather peers in addition to trackers and DHT. Peer exchange checks with known peers to see if they know of any other peers. With the 3.0.5.0 release of Vuze, all major BitTorrent clients now have compatible peer exchange. One of the options for this HTTP based tracker protocol is the "compact" flag. This flag, as defined in BEP 23, specifies that

322-580: The case that one tracker fails, the other trackers can continue to maintain the swarm for the torrent. One disadvantage to this is that it becomes possible to have multiple unconnected swarms for a single torrent where some users can connect to one specific tracker while being unable to connect to another. This can create a disjoint set which can impede the efficiency of a torrent to transfer the files it describes. Additional extensions such as Peer exchange and DHT mitigate this effect by rapidly merging otherwise disjoint graphs of peers. Vuze (formerly Azureus)

345-410: The original design of the BitTorrent file sharing protocol, peers (users) in a file sharing group (known as a "swarm") relied upon a central computer server called a tracker to find each other and to maintain the swarm. PEX greatly reduces the reliance of peers on a tracker by allowing each peer to directly update others in the swarm as to which peers are currently in the swarm. By reducing dependency on

368-548: The protest, many people had trouble downloading files on BitTorrent. From 5 December to 30 December 2014, the OpenBitTorrent website and tracker was unreachable, this may have been linked to the arrest of Pirate Bay co-founder Fredrik Neij . On 5 May 2015, the OpenBitTorrent tracker was back online although the website still did not display the tracker address. The website was shut down again in July 2017, but came back online for

391-449: The site. The method for controlling registration used among many private trackers is an invitation system , in which active and contributing members are given the ability to grant a new user permission to register at the site, or a new user goes through an interview process. There are several circumstances under which it is legal to distribute copyrighted material or parts thereof. There are also experiments that legally sell content that

414-420: The speed of peer discovery. Public or open trackers can be used by anyone by adding the tracker address to an existing torrent, or they can be used by any newly created torrent, like OpenBitTorrent . The Pirate Bay operated one of the most popular public trackers until disabling it in 2009 due to legal trouble. A private tracker is a BitTorrent tracker that restricts use by requiring users to register with

437-403: The swarm. Later development of distributed hash tables (DHTs) meant that partial lists of peers could be held by other computers in the swarm and the load on the central tracker computer could be reduced. PEX allows peers in a swarm to exchange information about the swarm directly without asking ( polling ) a tracker computer or a DHT. By doing so, PEX leverages the knowledge of peers that a user

460-402: The tracker came back online. OpenBitTorrent is powered by the opentracker software . The Pirate Bay also used the opentracker software, before they shut down their own tracker. From 16 July to 2 August 2012, OpenBitTorrent went offline protesting the lack of adoption of a protocol improvement by the makers of uTorrent, that was proposed by Pirate Bay co-founder Fredrik Neij . As a result of

483-446: The tracker can compact the response by encoding IPv4 addresses as a set of 4 bytes (32 bits). IPv6 addresses, though, are 128 bits long, and as such, the "compact" would break IPv6 support. To handle that situation clients and trackers must either avoid using compact announces over IPv6 or implement BEP 07 opentracker from Dirk Engling powered one of the biggest BitTorrent trackers, The Pirate Bay tracker. qBittorrent

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506-414: Was observed early on that both sites used the same trackers . The OpenBitTorrent project has countered by stating that the sites merely shared a tracker cluster operated by DCP Networks and Fredrik Neij during a startup period (February through August 2009). On 22 May 2010, the OpenBitTorrent tracker was shut down. This was a result of a case against The Pirate Bay by many major Hollywood studios. Later

529-780: Was the first BitTorrent client to implement such a system through the distributed hash table (DHT) method. An alternative and incompatible DHT system, known as Mainline DHT, was developed simultaneously and later adopted by the BitTorrent (Mainline), μTorrent, Transmission, rTorrent, KTorrent, BitComet, and Deluge clients. Current versions of the official BitTorrent client, μTorrent , BitComet , Transmission and BitSpirit all share compatibility with Mainline DHT . Both DHT implementations are based on Kademlia . As of version 3.0.5.0, Vuze also supports Mainline DHT in addition to its own distributed database through use of an optional application plugin MainlineDHT Plugin . This potentially allows

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