Torrents appear. Click. Download. Easy enough.

However, if a BitTorrent user doesn’t really know what he or she is looking for and needs some ideas, a torrent site’s category view comes in useful to allow browsing of specific content such as videos, music or games.

But what if there was another mechanism through which to find new content, one that doesn’t involve visiting a torrent site? One that would find content to download based on the activities of other BitTorrent users that have downloaded, to some extent, the same or similar content as you?

Now all of that is possible with “Swarm Discoveries”, a new and intriguing feature added to the open source Vuze client this week. The feature uses the Vuze Distributed Hash Table (DHT) to anonymously relate one piece of downloaded content with another.

The problem

“For a long time users have been asking for a means to find more content that they might like, stuff similar to the kind of things they already download,” Paul Gardner from Vuze tells TorrentFreak.

“Existing sites tend not to offer anything beyond simple categorization (e.g. by format or genre), and only cover their own domain of content – users are looking for something that works ‘horizontally’, across sites, while at the same time zooming in on things that may be of interest.”

Striving towards solving this problem the Vuze team came up with Swarm Discoveries, a behavior-based torrent content discovery system. So what makes it tick?

“Given the lack of any standardized metadata for torrents, and the huge diversity of naming conventions, languages etc., any approach based on matching between static torrent data is difficult. So what we decided to concentrate on was the behavioral aspects of torrent selection,” Gardner reveals.

“Users are already way smarter than us at finding content they like, so why not use their expertise to raise everybody’s game?”

And this is where it gets both slightly more complex and much more interesting.

How relationships are formed

“Swarm Discoveries is based on the fact that if Alice downloads torrents A, B and C then, in some (unspecified) way there is a link between A, B and C. At the most abstract the link is that Alice likes A, B and C,” Gardner explains.

“Now if Bob downloads B, C and D this re-enforces the fact that B and C are somehow related, but between them we know nothing regarding A and D.”

Of course, when looking at the habits of just Alice and Bob the dataset is very small. However, millions of people are using the Distributed Hash Table which results in a much larger sample and the creation of ever more interesting links between content.

As a side note, Vuze (or Azureus as it was then) debuted the first ever BitTorrent DHT.

Taking Swarm Discoveries for a spin

TorrentFreak gave the feature a test drive, and this is what happened when we tested it on a Fuduntu Linux distro we planned to test in a VirtualBox virtual machine.

1. First we loaded up the Fuduntu torrent using Vuze’s inbuilt torrent search feature. Once underway a right-click revealed the Swarm Discovery option.

2. Once selected this short list of related content appeared.

Item 1 is for a Knoppix torrent. Knoppix is another Linux distro so the connection to our Fuduntu download is obvious.

Item 2 turns out to be Hiren’s Boot CD, a collection of fairly geeky system management tools which is (coincidentally or not) based on Knoppix.

3. At this point the discovery can continue simply by right clicking on any result and selecting “Discover Related”. If you want to do some research on the torrents already found, the same menu gives access to some research tools.

4. Digging down another level produced further related results.

Of course, the system doesn’t work only for Linux distros. In our tests popular video and music content hashes produced the richest and most complex results.

I don’t want to do anything, just make it work!

For those of you too busy (or lazy) to right-click on downloads to find explicit results you can sit back and let Vuze do the work for you. Over time Vuze builds up results in the main Swarm Discoveries tab (you’ll find it under ‘Plugins & Extras’) and ranks them – the more ways a torrent is related to your downloads the higher the rank it will be assigned (up to a max of 100).

If you’re bored with the current results then right-click on sidebar entry and select ‘delete all results’, Vuze will start generating a new set to inspire you.

Decentralized and anonymous

Although the Swarm Discoveries system might at first appear to be a privacy nightmare, concerned users can rest easy. There are no external databases and relationship data is anonymous. (Not to be confused with anonymous downloads of course, that would require a VPN or similar)

“Swarm Discoveries is entirely implemented using the Distributed Hash Table (DHT) and results are automatically generated by Vuze clients – there are no centralized components,” Gardner explains.

“In the same way that the DHT is used to relate content to peers during decentralized tracking it is also used to related one piece of content to another – this relationship is stored anonymously, so when a Vuze client reads a relationship the originator of the relationship is unknown.”

While Swarm Discoveries often produced fairly predictable results, such as supplying torrents to similar genres of music and movies, it also throws in the occasional curve ball – perfect for those who browse YouTube for pop videos and end up two hours later viewing the mating rituals of a rare breed of mountain goat.

Download the latest version of Vuze with Swarm Discoveries here.

Source: TorrentFreak, for the latest info on copyright, file-sharing and anonymous VPN services.

The Pirate Bay argued that BitTorrent trackers have been made redundant by technologies such as DHT and PEX. In addition, The Pirate Bay team said that they might move away from torrents entirely and switch to offering magnet links instead.

“We’re talking to the other torrent admins on doing magnet links and DHT and PEX for all sites. Moving away from torrents and trackers totally – like pick a date and all agree ‘from this date, we’ll not support torrents anymore’,” a Pirate Bay insider told TorrentFreak at the time.

Now, two years later, that date is coming soon.

Today, The Pirate Bay made the first step towards this new future by making magnets the default download links instead of torrents. TorrentFreak was further informed that in “a month or so” the largest torrent site on the Internet will stop serving torrent files indefinitely.

The announcement is bound to lead to confusion and uncertainty among many torrent users, but in reality very little will change for the average Pirate Bay visitor. Users will still be able to download files, but these will now be started through a magnet link instead of a .torrent file.

The Pirate Bay team told TorrentFreak that one of the advantages of the transition to a “magnet site” is that it requires relatively little bandwidth to host a proxy. This is topical, since this week courts in both Finland and the Netherlands ordered local Internet providers to block the torrent site.

Perhaps even better, without the torrent files everyone can soon host a full copy of The Pirate Bay on a USB thumb drive, which may come in handy in the future.

Unlike the site’s users, existing torrent sites that scrape .torrent files from The Pirate Bay will have to make some drastic changes. If they want to continue serving .torrent files they will have to fetch them from DHT. Also, hotlinks to .torrent files will stop working and will soon redirect to The Pirate Bay’s detail page for the files in question.

One of the potential downsides of using magnets is that it could take a bit longer for downloads to start, especially if there are relatively few people sharing a file. This is because the .torrent file has to be fetched from other users instead of being downloaded directly from the site. More background on these and other technicalities can be found here.

The good news is that all mainstream BitTorrent clients support magnet links. This wasn’t the case back in 2009, but when The Pirate Bay hinted that in the future they could become a magnet-only site, all developers quickly made their clients fully compatible.

There’s no doubt that a torrent-less Pirate Bay will certainly mark the end of an era. At the moment it’s hard to predict what the impact of The Pirate Bay’s decision will be on the BitTorrent community. But torrents, however, will never disappear completely.

Source: TorrentFreak, for the latest info on copyright, file-sharing and anonymous VPN services.

However, the torrent eco-system didn’t collapse because in part TPB would rely on other BitTorrent features to facilitate transfers between peers.

Although they had been introduced years before, following this announcement the relatively obscure technologies of Magnet links, DHT and Peer Exchange would be thrust into the spotlight. From their quiet beginnings people suddenly wanted to know all about these trio of terms, which prompted us to create a user guide. The mainstream acknowledgement of the trackerless torrent had truly arrived.

While .torrent files continue to be the weapon of choice for most BitTorrent users, during the last year more and more sites have brought Magnet links on board, a development encouraged by the founders of The Pirate Bay. These days most of the major torrent clients support them.

As will become clear by the conclusion of this article, getting to grips with Magnets sooner rather than later may prove prudent. To this end, today we take a look at some addons, extensions, sites and services which make the use of Magnet links just a little bit easier.

Mainline DHT Plugin for Vuze

When DHT was first introduced back in 2005, the first client to implement it was Vuze (then Azureus). Unfortunately it uses a system that’s incompatible with those used in almost every other client. That means that Vuze users are cut off from everyone else. Not to worry though as with this Mainline DHT plugin, BitTorrent users are one happy swarm again.

The plugin can be downloaded here or through the client’s plugin installer.

Magnet Tracker

Magnet Tracker is a handy script that scans a web page looking for torrent hashes. The script then displays a window in the bottom right of a compatible browser window which allows the user to download a Magnet link. Magnet Tracker supports many of the main torrent sites and even offers functionality on Wikileaks in response to the site’s adoption of the technology last year.

As can be seen from the configuration window below, the script also allows for the customization of the Magnet link, such as with the addition of any number of additional trackers to add that extra downloading power should it be needed.

Magnet Tracker requires Firefox and GreaseMonkey to run and can be downloaded here.

Magnet Catcher

Continuing on the theme, Magnet Catcher strips the concept of adding Magnet links to a page right back. As can be seen from the before and after screenshots below, this script adds Magnet links straight to the main searchpage of a site containing torrent hashes, with no need to click-through to the torrent details page.

Magnet Catcher requires Firefox and GreaseMonkey to run and can be downloaded here.

Magnet Link Generator

If you already know the hash value of the material you want to download from BitTorrent, this basic webpage will convert it into a Magnet link.

Don’t let the foreign text put you off – simply paste the hash into the box and click the button and a Magnet link will appear. Click this and your client will pull its peers from DHT and PEX, no torrent site needed.

Go to Link Generator

Mgnet.me – The Magnet URI shortening service

As can be seen from the example below, one of the downsides to Magnet links is that they can be very long and therefore difficult to share.

magnet:?xt=urn:btih:d39ebe536d55ae4e422767f21eb997da11fe471c&dn=TorrentFreak.TV
.S02E12.HDTV.x264-TFTV.mov

Crucially they often have too many characters to be shared via Twitter, they are not clickable in IM apps like GTalk and MSN, and can be unfriendly on the eye. The Mgnet.me service changes all that.

Introduced earlier this year, Mgnet.me is a shortening service, much like Bit.ly or Tinyurl, designed specifically to convert Magnet URIs into shorter and more manageable links. As can be seen from the screenshot below, it also provides HTML code and a feature to post a newly shortened Magnet link directly to Twitter.

Go to Mgnet.me

Magnet Search Engines and Indexes

While many torrent sites are now offering Magnet links alongside the more traditional .torrent file, there are other sites which specialize in Magnet links only. The beauty for these sites is that they don’t have to carry .torrent files since they can generate Magnet links on the fly – as long as they know the hash of content in question that is.

Sailr

The first search engine in our list is the ultra-minimal Sailr. As shown in the screenshot below, this Magnet-only search engine has Mgnet.me implementation as standard.

Go to Sailr

BTDigg

BTDigg, is the first ever search engine for trackerless torrents. Rather than searching for .torrent files around the web like most engines, BTDigg scans BitTorrent’s DHT (Distributed Hash Table) to discover new files instead.

In theory, BTDigg should be able to discover any torrent sitting in a torrent client anywhere in the world, providing the torrent has DHT enabled in its settings. This means that torrents don’t even have to be uploaded to a torrent site, further decentralizing the BitTorrent ecosystem.

Go to BTDigg

Conclusion

Even though Magnet links (and their friends DHT and PEX) have been around for some time, the BitTorrent community has been relatively slow to adopt them as their primary route to content. The reason for that is a simple issue of supply and demand. While torrent sites, .torrent files and associated BitTorrent trackers remain in plentiful supply, most users will feel little need to make Magnet links their primary metadata choice.

However, that will all change when their favorite torrent site becomes censored by PROTECT IP or other blocking measures planned around the world.

In future – and armed with just a hash value – users may suddenly find themselves mysteriously attracted to Magnets.

Source: TorrentFreak, for the latest info on copyright, file-sharing and anonymous VPN services.

Every day millions of people are downloading files via BitTorrent, and in some instances more than 100,000 people are sharing the same file at the same time. These large ‘swarms’ of peers are great for sharing, but they also pose a threat as became apparent at the Chaos Communications Congress (CCC) recently.

In a talk titled “Lying To The Neighbours” it was shown that the DHT technology which powers “trackerless torrents” can be abused to let BitTorrent downloaders effectively DDoS a webserver of choice. DHT’s normal function is to find peers who are downloading the same files, but without communicating with a central BitTorrent tracker. This ensures that downloads can continue even when the central tracker goes offline.

According to the presenter who goes by the name ‘Astro’, Kademlia based DHT can be exploited by a malicious peer to carry out a DDoS attack. If there are enough peers downloading the same file, this could easily take down medium to large websites. The worrying part is that the downloaders who are participating in the DDoS will not be aware of what’s going on.

“The core problem are the random NodeIDs. The address hashing and verification scheme works for scenarios like the old Internet, but becomes almost useless in the big address space of IPv6,” Astro told TorrentFreak in a comment. As a result, any BitTorrent swarm can be abused to target specific websites and potentially take them down.

This and other DHT vulnerabilities are not entirely new concepts for BitTorrent developers. They have been discussed in various places already, but no agreement on how they should be dealt with has yet been reached.

Over the last months DDoS attacks have been in the news regularly, mostly carried out under the flag of Anonymous’ Operation Payback. Initially anti-piracy targets such as the MPAA and RIAA were taken offline, and last month the focus switched to organizations that acted against Wikileaks, including Mastercard and Paypal.

While these attacks required hundreds of people to actively participate and fire up their LOIC application at the same time, the BitTorrent DDoS could take down the same sites from a single computer, using BitTorrent downloads as a ‘botnet’. But, where there’s a problem there’s a solution, and Astro has some pointers for BitTorrent developers.

“Not connecting to privileged ports (< 1024) where most critical services reside," is one ad-hoc solution, but Astro says that since it's a design error, the protocol has to be redefined eventually.

The idea of using BitTorrent as a DDoS tool is not entirely new. In fact, researchers have previously shown that adding a webserver’s IP address as a BitTorrent tracker could result in a similar DDoS. The downside of this method is, however, that it requires a torrent file to become popular, while the DHT method can simply exploit existing torrents that are already being downloaded by thousands of people.

It will be interesting to see if BitTorrent developers are going to act upon the DHT vulnerability in the coming months and come up with a solution to prevent this kind of abuse.

Source: TorrentFreak, for the latest info on copyright, file-sharing and anonymous VPN services.

The Pirate Bay boasted the title of “the world’s largest BitTorrent tracker” for half a decade, but a year ago this title no longer applied. On November 17, 2009 The Pirate Bay decided to shut down its tracker for good. According to the Pirate Bay team central trackers had become obsolete.

“Now that the decentralized system for finding peers is so well developed, The Pirate Bay has decided that there is no need to run a tracker anymore, so it will remain down! It’s the end of an era, but the era is no longer up-to-date,” the team announced.

The Pirate Bay argued that BitTorrent trackers have been made redundant by technologies such as DHT and PEX. In addition, The Pirate Bay team said that they might move away from torrents entirely and switch to offering Magnet links instead.

“We’re talking to the other torrent admins on doing magnet links and DHT and PEX for all sites. Moving away from torrents and trackers totally – like pick a date and all agree ‘from this date, we’ll not support torrents anymore’,” a Pirate Bay insider told TorrentFreak at the time.

The announcements led to confusion and uncertainty among many torrent users, but in reality very little changed for the average torrent user. The Pirate Bay’s dominant position as a tracker has been taken over by two new ones, and even after a year .torrents are still available on The Pirate Bay.

What was interesting to see, however, is the response that came from the development community and torrent site owners. Before last year most torrent clients didn’t have support for Magnet links, and those that did spent little time on making them compatible and easy to use. However, after The Pirate Bay’s call for Magnet support this quickly changed.

BitTorrent clients such as Transmission, BitComet and Ktorrent all implemented support for Magnets this year. The clients that already offered Magnet support, such as uTorrent and Vuze, didn’t sit still either and spent time optimizing their implementation.

Similarly, the operators of other torrents sites were also listening in and nearly all of the larger torrent sites that didn’t already offer Magnet links soon added them. In January, this was followed by the launch of the first ‘Magnet-only’ torrent index named TorrIndex. Clearly, the words uttered by The Pirate Bay operators had not been in vain.

As for the tracker that was shut down, aside from the sentimental value it hasn’t really been missed. OpenBitTorrent and PublicBitTorrent quickly took over and have been going strong ever since, and not without a reason.

Larger torrents with thousands of peers will work just fine without a central tracker thanks to technologies such as DHT and PEX. But the majority of torrents out there only have a handful of peers and for these files a central tracker is still an essential part of the downloading process.

The shut down of The Pirate Bay tracker last year marked the end of an era, but as it stands now BitTorrent trackers are not defunct yet.

Source: TorrentFreak, for the latest info on copyright, file-sharing and anonymous VPN services.

However, the addition of Transmission to openSUSE was not straightforward. Since Transmission comes with DHT support – a technology that helps BitTorrent users to find peers – Novell thought that the application could possibly make openSUSE liable for copyright infringement under German law.

In order to avoid legal problems, Novell and openSUSE therefore decided to ship the operating system with a DHT-less version of Transmission while they tried to work out a solution with their lawyer.

“This month’s new release of their openSUSE Linux distro now ships with Transmission as the default BitTorrent client, but with DHT support removed at compile-time due to perceived German legal risks,” Transmission developer Charles Kerr told TorrentFreak.

After discussion with Novell’s German lawyer, it was agreed to include Transmission with DHT in future releases, but with an added popup informing users that they should only use the BitTorrent client for legal transfers. This means that the next openSUSE release will include a fully-functional BitTorrent client.

Charles Kerr told TorrentFreak that he is happy with the outcome, especially since Transmission will also add support for Magnet links in their upcoming 1.8 release.

“Magnet links are much more useful when DHT is available, so I’m glad it will be included in the next openSUSE release,” he said, adding that openSUSE have been very helpful and communicative, which is why there’s a better resolution in the works for the next openSUSE release.

Still, one can’t help but wonder if Novell had legitimate concerns, or was maybe a little paranoid in handling the DHT issue. That said, if BitTorrent indeed comes to rely more on trackerless torrents and DHT in the future, could BitTorrent clients potentially become a target for the entertainment industry?

Source: TorrentFreak, for the latest info on copyright, file-sharing and anonymous VPN services.

The key thing to understand is that nobody is being forced to use Magnet links or trackerless torrents. While these long-standing technologies may prove to be the future, they will co-exist with tracker-enabled torrenting for quite some time. For now, nobody will be forced to immediately change their existing downloading habits, although it may be wise to switch to a BitTorrent client that is compatible with these technologies.

In an attempt to clear some of the mystique surrounding DHT, PEX and Magnet links we will walk through all three briefly, hoping to assure those who’ve become confused earlier this week.

DHT

Using DHT instead of trackers is one of the things The Pirate Bay is now trying to encourage, and torrent downloads that rely solely on this technology are often referred to as “trackerless torrents.” DHT is used to find the IP addresses of peers, mostly in addition to a tracker. It is enabled by default in clients such as uTorrent and Vuze and millions of people are already using it without knowing.

DHT’s function is to find peers who are downloading the same files, but without communicating with a central BitTorrent tracker such as that previously operated by The Pirate Bay.

DHT is by no means a new technology. A version debuted in the BitTorrent client Azureus in May 2005 and an alternative but incompatible version was added to Mainline BitTorrent a month later. There is, however, a plugin available for Azureus Vuze which allows it access to the Mainline DHT network used by uTorrent and other clients.

Peer Exchange (“PEX”)

Peer Exchange is yet another means of finding IP addresses. Rather than acting like a tracker, it leverages the knowledge of peers you are connected to, by asking them in turn for the addresses of peers they are connected to. Although it requires a “kick start”, PEX will often uncover more genuine peers than DHT or a tracker.

Magnet links

Traditionally, .torrent files are downloaded from torrent sites. A torrent client then calculates a torrent hash (a kind of fingerprint) based on the files it relates to, and seeks the addresses of peers from a tracker (or the DHT network) before connecting to those peers and downloading the desired content.

Sites can save on bandwidth by calculating torrent hashes themselves and allowing them to be downloaded instead of .torrent files. Given the torrent hash – passed as a parameter within a Magnet link – clients immediately seek the addresses of peers and connect to them to download first the torrent file, and then the desired content.

It is worth noting that BitTorrent can not ditch the .torrent format entirely and rely solely on Magnet links. The .torrent files hold crucial information that is needed to start the downloading process, and this information has to be available in the swarm.

Pirate Bay links cf. Mininova links: When the Magnet link specification first came out, in January last year it called for a particular format (“base32 encoded”). The links that EZTV, Mininova and ShareReactor have displayed for some time all conform to that original specification. In May of last year the specification was changed, in favor of “hex encoding”, and that is the format of the links being displayed by The Pirate Bay. Torrent clients should accept either format.

Compatible Clients

All the main torrent clients: uTorrent 1.8.5, Vuze 4.3.0.2, BitTorrent 6.3, BitComet 1.16, and Transmission 1.76 (and others) support Peer Exchange and DHT (via a plugin in the case of Vuze). Neither BitComet nor Transmission yet support Magnet links but Transmission is planning to include Magnet link support in the upcoming 1.8 release. Bearing in mind that no site, including The Pirate Bay, has yet abandoned support for traditional torrent files, there is plenty of time for support to be added.

We hope that this article has cleared some of the smoke that was generated by The Pirate Bay’s announcements earlier this week. There is no need to panic, cry or be angry, and it’s not a problem if you’re still confused after reading this article. Torrents will still be available and aside from some extra downloading options thanks to sites that add Magnet links, nothing drastic will change in the near future.

Props to ‘Adapa’ for contributing to this article.

Source: TorrentFreak, for the latest info on copyright, file-sharing and anonymous VPN services.

The main problem is that most people just don’t understand what DHT is, what it does, and how it works. Not really a surprise since the documentation and even the Wikipedia page are filled with technical jargon, and no simple explanation.  Without that basic understanding confusion is inevitable. We did explain DHT in our jargon piece back in 2006 but after 3 years, we decide to cover it again.

The easiest way to think about DHT is to imagine it as a form of ‘super tracker’, in some ways a lot like WinMX and Kazaa of old. A large ad-hoc network of peers pass on information requests about torrents without a central server, meaning no control or single point of failure. No information about the contents or even the names of torrents are passed around, making this legal and hard to shut down.

Myth: You must turn off DHT when you use private trackers.

Wrong — There is an element to a torrent that is called the ‘private flag’. It’s a small flag that marks to a client that the torrent is ‘private’ and disables any method of sharing peers (including DHT), except via the tracker. This flag also changes the hash, so peers on a non-flagged torrent could not connect to a flagged torrent in any case. Most private torrent sites check for the flag, and add it if missing when the torrent is initially uploaded to their site.

Myth: Certain clients leak DHT data and should be avoided.

Wrong (with one exception) — There are always going to be people that want control. When it comes to torrent sites (especially the private ones) they like to express their control through lists of clients you can and can’t use (a form of DRM) and sometimes give reasons to support this. An example would be this statement from a staff member at a private tracker:

Not all torrent clients respect the private flag. But if you are using a client like Vuze, uTorrent or similar if the private flag is on (set by the tracker) the DHT, peer exchange settings etc are ignored. However, if you are using something like BitComet, BitLord or their ilk they ignore the private flag so if you have DHT etc enabled it is going to be enabled no matter what.

This statement is completely false. All torrent clients that support DHT respect the flag. The flag is set by the torrent file, not the tracker (although the tracker can add the flag to the file, it’s still set by the torrent), and BitComet does NOT ignore the flag. The one exception is a single build of BitComet (0.60) that was available for 2 weeks at the end of 2005, and even then, was a fallback only if the tracker was unable to be contacted for a 30minute period. Bitlord is unable to leak to DHT, as it doesn’t use DHT at all.

If you see staff making claims like this, it’s a good indication that the staff is clueless, which might be an idea to leave that tracker. If they can’t get the basics right who knows when else is wrong. Of course, we ask those claiming other clients leak to let us know so we can test it.

Myth: You can be tracked by DHT / AntiP2P groups use DHT to find you

Unlikely — It’s much easier and simpler to use the tracker. Blocklists, used on your client and on the trackers, are generally ineffective and easily circumvented through the use of residential connections. Last year’s University of Washington study showed that they will send letters just based on tracker info.

Myth: DHT slows your system down

Generally not true — It can slow down your connection depending mainly on network hardware. The actual data used in running DHT is low, generally less than 1kilobyte a second. Some routers and modems, however, can have problems with DHT causing lockups and restarts if they run out of ram. This mostly happens with lower spec ‘home’ equipment (such as older Belkins, Netgears and D-links), or telco-provided hardware.

Myth: You need to connect to a tracker, before you can use DHT

Wrong — When DHT is enabled (certainly in uTorrent) it connects to a bootstrap node (such as router.utorrent.com or router.bittorrent.com for mainline, or dht.aelitis.com for Vuze) and uses that to enter the DHT ‘swarm’. It’s handed a set of DHT nodes and uses that to build up a small group of connected nodes. Those nodes are then used to get peers. No tracker is required at any time.

Myth: When enabled, it sends usage data back to [insert company]

Wrong — This is another case of people not knowing what they’re talking about. Generally they’re misinterpreting the bootstrap node connection for their client.

When the demonoid tracker was finally resurrected last year, many of it’s torrents were still active thanks mainly to DHT. DHT with Peer Exchange (PEX) is a very powerful addition to the torrenting world, and allows torrents to stay active, irrespective of the trackers stability or even existence. Also, Azureus/Vuze users, despite having their own DHT system, can join in using a mainline DHT plugin.

Should you use DHT? Not if you only use private trackers, but if you use public ones and your network hardware can cope, then yes. It can help reduce tracker load. If you have a question about DHT not answered here, then again, let us know.

Source: TorrentFreak, for the latest info on copyright, file-sharing and anonymous VPN services.

Torrents are deleted from trackers
Some trackers, like Demonoid.com have policies that require them to remove torrents from a tracker if they are older than a year. This way they save server resources, because a lot of the older torrents are unseeded, but still indexed by some sites, which means that the tracker is bombarded with unnecessary requests.

Trackers Die
Unfortunately BitTorrent trackers don’t live forever.

Trackers experience Downtime
A lot of BitTorrent trackers go down every now and then. Most of the time they return after a few minutes or hours, but still, the torrent won’t work when they’re down.

So, how do we solve this problem? Basically, there are two things you can do to guarantee that your torrent will stay alive. Of course these tips will only work with public trackers.

1. Use Multi-tracker Torrents
Several BitTorrent clients allow you to add multiple trackers to a torrent upon creation. So, if you add three trackers, the second one will take over if the first one fails. The multi-tracker feature was first proposed by John Hoffman, and is now supported by several clients including Azureus, BitComet, BitTornado and uTorrent.

2. Enable DHT
DHT stands for “Distributed Hash Table”. If a web based tracker goes down, the torrents stay alive because peers can act as “nodes” keeping the swarm intact, and the torrent alive. So you could say that the DHT layer serves as a peer-to-peer tracker. The DHT feature is available on Azureus, Bitcomet, uTorrent and several other BitTorrent clients.

Do these two things and your much less likely do develop a headache when you’re favourite Linux distribution stops downloading. ;-)

Source: TorrentFreak, for the latest info on copyright, file-sharing and anonymous VPN services.