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Unexpected S-flag


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Something weird perhaps: Was in a very small swarm (5 seeds, 4-6 peers, all from DHT/PEX except for 1 seed and 1 peer from tracker). Everything went very smooth but once I finished downloading all the peers left suddenly showed an S-flag. Only way I was still uploading was by optimistic unchoke. Only after an hour or so connected to a few peers from tracker without S flag and was able to seed as normal.

No idea what happened, never noticed anything like that before. Any possible explanation ? This was 1.8 btw, my up speed is about 11-12 kB with three slots.


P.S. Perhaps I should have mentioned that after watching that snubbed/optimistic unchoke horror for more than half an hour I disabled DHT/PEX. Something I normally do to begin with but this was mostly a DHT/PEX thing in the first place and hate to abandon somebody I downloaded from until he gets the entire thing too. Two people from that swarm now show up again, via the tracker I have to assume. No S-flags.

People are reading this post apparently but nobody is saying anything. If this is a FAQ thing or in case I'm just being terribly stupid could somebody be kind enough to at least tell me so, just to acknowledge my existence so to speak.

Thanks again.

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@Ultima Moderator

Thanks for your reply. No, initial seeding not enabled. Should I have done that under the circumstances ? Please tell me, I'm feeling a bit clueless here.

I'm seeding as normal now so I'm not particularly concerned. It was just something I think should not have happened.


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Is your ISP hostile to BitTorrent traffic?

That might cause uTorrent to think it couldn't upload to peers.

We know little about what settings you're trying (and failing?) to use in uTorrent, nor the speed of your connection both down and up.

Without that information, I cannot even make a reasonable guess about the problem's cause...

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Thanks for your reply.

It's not as if I'm messing around with settings. I've studied settings really long and hard and have been using uTorrent, using those settings, for more than 200 torrents.

My ISP I assume, is blissfully unaware. And if they were not they would not care I'm certain.

If you feel confident this has anything to do with my settings or my ISP, than so be it. I was trying to report something odd which happened to me, for the very first time, being part of a very small swarm which was working wonderfully until I finished downloading.

Perhaps something odd happened, maybe I was suddenly the only seed left on the tracker, what ever.

I love uTorrent and in case I can help by providing my settings, wonderful. But you will not find anything peculiar I dare to guarantee.

My reason for posting was being concerned about a potential flaw. I could have simply ignored the problem, deleted the torrent,and move on to 202. Don't make this look as if it is my problem because it isn't.

Kind regards

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@ Switeck

Up 11 kB, 3 slots

Connections per torrent 32, global 128

Max active torrents 4, max act downloads 2

Port (51000) properly forwarded

Net half open: 50 (used lvlord)

Was in a very similar situation 3 days later with 3 peers left but this time 3 seeds left on the tracker and nothing peculiar happened. Just started seeding as usual and showed up on the tracker as seed after updating. No S + O flags.

P.S. : Starting to wonder whether perhaps you were right assuming this has to do with my ISP.

Swarm I'm in right now had two trackers, one from the pirate bay and some obscure tracker which will show a lot of Chinese stuff when you look for the web page.

That "Chinese" tracker, after a while, showed "connection closed by peer", then went off-line, than worked again, then again showed "connection closed by peer" again etc. That ought to have something to do with traffic shaping but why only one tracker? Eventually just deleted that tracker. Didn't seem to have any seeds in addition to tpb tracker, total number of seeds/peers stayed the same.

Sorry if it took me a while to respond but I just wanted to figure out first whether it would reproduce.

I'm not using anything like Peerguardian but all traffic is encrypted. I live in Philippines and it is somehow hard to believe my ISP gives a hood. Didn't see anything on local blogs to suggest that.

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Set net.max_halfopen back to 8. Making and breaking new connections at the rate of 50 at once...is INSANE! ...especially for a slower connection like yours.

3 upload slots and 4 active torrents means 12 total upload slots possible.

But you're only uploading at a max of 11 KB/sec...really short-changing everyone. :(

uTorrent will reduce the upload slots per torrent if you upload too slowly...which can possibly cause weird snubbing effects because of exceeding uTorrent's upload slot limits.

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You asked for my settings. I hardly ever have more than one active torrent. If I do, I make sure the total number of slot doesn't exceed 3.

Sorry to say so but when you asked me about my settings I could see your reply coming from miles away. Irony is that I probably posted something rather similar on various torrent sites about 20 times over the past year.

11 kB isn't all that much but in 3rd world countries a decent up speed is often prohibitively expensive (I pay 25 US$ a month just for that 11 kB). I have to manage with what I have and in small swarms (and I'm often in small swarms), when ever I see a good peer I sometimes even go to a single slot just to stay on his good side.

Guess we'll never know what happened but in that swarm I was talking about in my initial post, it was the only active torrent and I was uploading via three slots (average 3.5 kB to each of them), until I finished downloading. And bang, all peers showed an S-flag and I was only uploading one piece at the time to one peer at the time, dependent on whose turn it was showing an O flag. Never saw that before and never saw that since.

Let's just leave it at that. If you're not concerned about whether it has anything to do with uTorrent, I'm not concerned either.

Take care.

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Worked in materials engineering for 25 years. Don't know too much about TCP protocols and stuff. But I did know the stuff I needed to know to do my job properly and help out people who would come to me with questions.

Already answered the question about initial seeding 22nd of October, it's never on. Perhaps 50 half open is "stupid" but 95 % of the time up and down is both maxed out so who cares. And what does it have to do with S-flags?

Are you sure you are having any fun moderating this forum ? Operating a photo copy machine might be a little less stressful. Or flipping burgers or something ....

Just some suggestions to make your life a little easier. You just don't strike me as a terribly bright bulb.

I've now already been accused of short-changing everyone and been called stupid. After posting a problem which occurred during seeding. How old are you exactly? 16 or something?

Way to go! Keep up the good work.

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Windows has a limit of 10 half-open connections per second. Setting it higher is pointless and screws things up. Yes, you can patch tcpip.sys, but that gets reset often and is just asking for trouble. Furthermore, a lot of routers suck and the increased connection rate tends to make them less stable, or slow down more than they should.

Don't insult my staff. Switeck actually does know what he's talking about. Your high half-open setting is silly (why did you raise it? Did you even know what it did?), and without the clarification that you don't ever really have more than one running torrent, 3-4 torrents with 3 upload slots each on 11kbyte/s upload is screwing the swarm.

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Well "Don't bite the hand that feeds you" comes to mind. If you come here for help... it's at minimum bad form to be disparaging to someone who spent their TIME, their FREE TIME, free VOLUNTEER TIME looking/thinking/helping you with your problem.

If ISP interference is the cause, have you tried keeping a "background" download going at a set low download rate to see if upload will keep up that way?

Perhaps as more and more people get into trouble with stupid settings and the alternate settings Switeck made up and others (me included) reference could make it into the EXE.

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So when you come here for "help" (I merely reported something weird regarding S-flags I actually thought you wanted to know, I didn't come here for "help", I was the one who was trying to "help" in my perception), I have to indulge in ...... "insane", "stupid", "... short-changing everyone :(".

Is that how things work here? A moderator gets to picture me as a complete moron ... I somehow don't think complete morons ask too many questions about flags.

I may be completely wrong about that 50 half open under the circumstances and my router probably "is" crap. But that 50 is in every "speed guide" on the Internet (used the one from filesharefreak I think). And it doesn't ever get reset btw. But I accept that I didn't really know how to relate that to my connection and I will set everything back to default.

But please, please, please .... This was the first time in 200 torrents that ever happened, and after I switched from 1.7.7 to 1.8. So I thought it might actually have something to do with the software ... Shoot me.


Another flag thing but hardly dare posting anymore : Somebody in my current swarm with K flag for 2-3 hours. Uploaded > 20 MB and downloaded 256 kB. What good is a K-flag if I keep uploading ? That 20 MB could have been deployed much, much better. Disabled DHT/PEX, just couldn't get rid of him. The peer is using Transmission 1.34. With all other peers up/down is within 30 %.

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But that 50 is in every "speed guide" on the Internet (used the one from filesharefreak I think).

Not every guide has it. Only guides written by people who have no clue what effect it actually has. The benefit to a torrent for an increased halfopen limit is negligible in the first minute and completely nonexistent after that.

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Ok, no problem. I'll set everything back to default. Maybe it was a hardware thing.

Thank you.

P.S. Any comment on that K-flag by chance?


Except for that 50 half open I didn't change "any" of the uTorrent default settings for my connection, starting with 1.7.7. I learned the hard way not to have more than one active torrent. I figured it out myself. So if those settings are stupid it is because the default settings were stupid. Guess you and I will never really get to like each other very much.

From your own guide: "The pitiful 80 kilobits/second setting ...." .... Best thing I could get under 80 US$ a month is 125.

Care to live where I live ? I really, honestly, quite seriously don't like you.

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