Peers not connecting/disconnecting/snubbing utserver.

[Ersan]

I think this is probably my fault but I've been trying for days and can't figure out the problem.

I've had alot of problems getting peers to connect to utserver (tried several revisions), when I try to download a torrent with a swarm utserver is a part of, clients will often attempt to download (d flag) but will never start receiving data. Sometimes they will get utserver to respond (D flag), but will get snubbed (S flag)... And a LOT of the time clients will connect and get to a high speed (around 2MB/s) and then randomly disconnect or drop the speed slowly down to 0 until it is disconnected, is there any way to tell what's going on? It's hard without a way to debug it and even harder without a peer list.

[Ersan]

It's not hitting maximum halfopen connections, or maximum peers per torrent, I've tried with uTP and without, net.low_cpu on and off, the disk I/O is pretty low, the bandwidth being used is FAR less than the line is capable of... It's driving me crazy.

Okay, Ultima helped me figure out how to get the raw JSON for the peer list, and it seems like randomly utserver will choke a peer for no reason (they change to the 'u' flag) in the middle of them downloading at high rates or often just disconnect the peer completely (though this may be ISP hostility, this occurs on comcast).

Alright, got debugging working (sorry I'm an idiot), gonna take a look at it.

I see this in logs when the utorrent can't connect to utserver (uTP disabled):

[00:09:23]  XXX.XXX.XXX.XXX:55106(TEST-TORRENT): [uTorrent 3.0 (0.3)]: Got Request: 62:933888->16384
[00:09:23]  XXX.XXX.XXX.XXX:55106(TEST-TORRENT): [uTorrent 3.0 (0.3)]: Sending Piece 62:933888->16384
[00:09:24]  XXX.XXX.XXX.XXX:55106(TEST-TORRENT): [uTorrent 3.0 (0.3)]: Got Cancel In Queue: 62:933888->16384
[00:09:24]  XXX.XXX.XXX.XXX:55106(TEST-TORRENT): [uTorrent 3.0 (0.3)]: Rejecting 62:933888->16384
[00:09:24]  XXX.XXX.XXX.XXX:55106(TEST-TORRENT): [uTorrent 3.0 (0.3)]: Got Request: 62:950272->16384
[00:09:24]  XXX.XXX.XXX.XXX:55106(TEST-TORRENT): [uTorrent 3.0 (0.3)]: Sending Piece 62:950272->16384
[00:09:25]  XXX.XXX.XXX.XXX:55106(TEST-TORRENT): [uTorrent 3.0 (0.3)]: Got Cancel In Queue: 62:950272->16384
[00:09:25]  XXX.XXX.XXX.XXX:55106(TEST-TORRENT): [uTorrent 3.0 (0.3)]: Rejecting 62:950272->16384