[CentOS] Trackerless torrents (was: Can't connect to torrent tracker)

William L. Maltby CentOS4Bill at triad.rr.com
Thu Dec 20 19:02:47 UTC 2007


On Thu, 2007-12-20 at 17:43 +0100, Kai Schaetzl wrote:
> 1198111906.5525.38.camel at centos01.homegroannetworking>
> X-Rcpt-To: <centos at centos.org>
> 
> William L. Maltby wrote on Wed, 19 Dec 2007 19:51:39 -0500:
> 
> > Ah, yes. It sounds so simple. But I've been perusing the various
> > references available (bittorrent ones are sparse - no man pages) and if
> > I want to seed beginning with the ones I've already downloaded, it seems
> > to get more complicated.
> 
> I think you are trying to seed a *new* "unofficial" torrent. That's not 
> what you want to do. See below.

Yep, it was what I wanted to do then either!  :-{
But in my learning curve, thinking I needed a local torrent to get
started ...

Anyway, it didn't take long to realize the implications of that and stop
it.

> 
> > 
> > I presume this assumes I'm downloading originally. Then, if starting in
> > tracking mode, how does one switch to "trackerless" or DHT? From reading
> > some of the refs in other posts, it seems that I would need to be
> > downloading from a client that supports the DHT schema. Meaning that
> > when I start downloading, my presence is added to the hash (or is it
> > routing?) tables and forwarded to peers in the network and I would have
> > to receive them also. Does the service CentOS is using support all this?
> 
> It doesn't need to support this. The important thing is that *you* have to 
> use a DHT client. utorrent uses this automatically (you can switch it 
> on/off in the options, though). So, you have to look in the client 
> documentation if and how it supports DHT (which seems to be the 
> abbreviation for Distributed Hash Table).
> What you then simply do is fire up that client and get the CentOS torrent 
> and keep it running once you got it. That's all. In case there's no 
> tracker connectable DHT-aware clients will talk to each other and look for 
> the hash. Which means if you already got it you can serve it. Or if you 
> don't have it yet you can get it from others. Without a tracker. 
> The important part is that all the DHT clients use the same torrent file 
> for starting up the download. If you download the file by other means and 
> then start seeding it (by creating your own torrent file and uploading it 
> to a tracker) you start a new torrent "cloud" or whatever you want to call 
> it.
> I'm sure there are ways to "trick" around this and use an existing torrent 
> file with data that were downloaded a different way. Maybe just start a 
> download, stop it and then replace the file with a complete one.

Through experimentation, I found it's even better than that: no trickery
needed!

With bittorrent, I simply positioned myself in the correct directory,
configured things, and fired up the torrents (genuine CentOS ones). Even
though the stuff was downloaded via conventional http methods, the
images and *sum files were seen by bittorrent, the checksums were run
and the images began immediately acting as seeds. Lots of peers came on
board and began downloading from these images. No downloads to me were
attempted. Last run of

   strings ~/.bittorrent/data/routing_table | wc -l

shows 188 IP addresses. Some from the -curses and some from the GUI, I
suspect. I wonder if they are stepping on each other here? No matter for
now.

When I fired up the -curses version, I specified --
start_trackerless_client (IIRC, thats how it's spelled - bash_history
will remember for me) and it worked fine.

I just need to find a way to make sure that it can't find a conventional
tracker to see if that parameter has the desired effect. From what you
say, and what I think I've learned, should work OK. And may not even be
needed.

I note that there are 5.2.* and 6-beta versions of bittorrent available.
I though I might see if the prerequisites for them are on my 5.1 CentOS
(that my "experimental" node) and take my first shot at making an RPM to
contribute back to the community (rpmforge seems to be the appropriate
target).

> 
> Here's what's currently getting seeded:
> http://www.mininova.org/search/?search=Centos+5.1
> The seed/leech ratio seems to be ok.

I book-marked that. Thanks.

> 
> 
> Kai
> 

Thanks to you and all who helped me get started on this.

-- 
Bill




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