BitTorrent leeches

[neddie]

So we all know that the idea of BitTorrent is that you keep seeding after your download has finished, to help the network distribute the data to the people who haven't got it. It's the "good thing" to do, and people who don't do it are described as "leeches", those who aren't cooperating. I read somewhere that the software tries to determine who is a leech or not, and preferentially divert traffic to other nodes in that case.

 

What I don't get, is how can it possibly know if one node is a leech or not? Surely it only becomes a leech _after_ it has finished its download and disconnects from the network, only _then_ does it become a leech, and then it's too late for the network to do anything about it. The network has to distribute packets to those who are at less than 100% (that's its job), and doesn't distribute any packets to those who have finished downloading (cos they've already got everything). So I can't see a way for the network to control who's leeching and who's not.

 

Unless of course the network somehow knows about the other torrents you've downloaded in the past, and whether you've got low share ratios for those other torrents, but that would be surprising if that information was available. The torrent client knows this of course, or could know this, but that would be a sneaky client which snitched to the network about your previous leeching. And since you can use any of many clients, people would naturally choose a non-snitching one, wouldn't they?

[tyme]

Most torrent clients keep a count of your download/seed ratio. Azureus does this, and shows it to you. That doesn't necessarily mean it's reporting it to any of the torrents your grabbing. Most of the time, the torrent doesn't actually care what your ratio is. Only some torrent repo's keep a track of your download/seed ratio, and then it's only for torrents on their network.

 

I do not believe that the client reports to the network what your ratio is, I believe some networks keep their own records, especially ones that require you to login before being able to get any of the torrents.

 

Technologically, there is nothing actually in the bittorrent protocol which is designed to thwart leechers. There are things available that can be used to do so, but this is often done on the server side, not on your client, as I suggested...

 

Also note that one way to detect a leecher is to look at their upload speed and if it's extremely low, there's a good chance that they're a leecher (one would assume they purposely set it this way, as most clients allow you to). Of course, going this route you'd have to be sure that they weren't a dial-up user (or just had a slow up-stream connection).

[ianw1974]

I was under the impression a leecher was one who was downloading and it wasn't a complete download. After it was a complete download, they became a seed.

 

At least, this is what I remember it saying in the azureus gui to me when I moused over it ages ago when wondering.

 

EDIT:

 

Found this:

 

http://howtobittorrent.blogspot.com/search...rrent%20Program

 

While you're downloading the file, you're called a Leacher because you don't have the complete file yet.

 

EDIT:

 

also found ones that say they download but don't share it back. Same terminology but different explanation for the word.

[jkerr82508]

The Azureus GUI refers to those who do not have the whole file as "peers". I prefer that description. Leech implies (to me at least) something rather unpleasant.

 

I think some bittorrent clients restrict the download speed if you are not uploading in a "fair" way. I have no idea what rules they apply in doing this, but they probably vary from one client to another.

 

Jim

[neddie]

I was under the impression a leecher was one who was downloading and it wasn't a complete download. After it was a complete download, they became a seed.

yeah, I've heard that description too. But for me "leech" implies something parasitic, like a freeloader.

 

So my question was, is there any way for the network to detect if people are "playing fair" (ie, continuing to seed after completing the download) or just disconnecting as soon as the download is done. And if there was a way for the network to react to that. My impression was that it can't do anything about it, because it doesn't know whether someone will disconnect or not (unless it knows what the client did for other torrents). And what tyme says seems to back up that idea - it's just a netiquette thing.

 

I guess if it was a "private" torrent which required a login (if such a thing exists?) then it could track your previous behaviour, but then there would be a nice audit trail of which torrents you had downloaded, which also might not be desirable.

[ianw1974]

I'm wondering if the client logs it, and they read this from your client config to determine whether you are a leacher or not.

[neddie]

I'm wondering if the client logs it, and they read this from your client config to determine whether you are a leacher or not.

Yeah, that's what I meant by "snitching" in my first post. But then you just choose a client which doesn't snitch.

[ianw1974]

Or disable the feature if it's available. I can't see of any other way they would know really. And, if you're IP changes, it'd be hard to do you by IP, so would have to be the client.

[tyme]

I don't believe that the client "snitches" on you to the torrent. I've never heard of this, or experienced it, and I've certainly leeched at times.

 

A leecher, in torrent terms, is usually used to refer to someone who doesn't upload after finishing their download. Normally, users are labeled "peers" or "seeders" - the former being someone who is still downloading, the latter a person who is sharing the file after their download is complete.

 

Most "private" torrent networks, that require username/password and track your downloading/uploading ratio don't punish people for leeching - on the contrary, they usually reward non-leechers, i.e. if you seed a given amount of data you get to invite others to the "private" network.