Torrent causing spikes in LAN traffic

[powblock88]

Win7 64bit

uT: 2.0.3

I've been using 2.0.2 for a while now, and recently switched to 2.0.3. This version seemed to work just fine with the settings that I'd been using this whole time, with me being able to download/upload several torrents now. Then I added a new torrent, not changing any other settings, and now my LAN traffic as seen with Task Manager, spikes up to 100% every 10 or so seconds. Actual speeds as seen by uTorrent are quite different, usually only a couple kb up and down, all the while causing web browsing to suffer horribly.

If I stop the torrent, the problem goes away, but I've never heard of a torrent file causing problems. All the trackers are ones that I've used before, as is the site I got the torrent from. Dropping the max peers/torrent to 10 gets rid off 95% of the traffic spikes, but not all. It had been set to 100 with zero problems for years.

Is there any clue as to what is causing this to happen and how to resolve it, or could it just be a very odd torrent file bunging things up?

[Switeck]

I assume you're using Teredo/IPv6 peers/seeds and also uTP peers/seeds?

What about DHT, Local Peer Discovery, and Resolve IPs?

bt.connect_speed and net.max_halfopen both set to 8 or less?

[powblock88]

I believe so, the "Logger" tab says "IPv6 is installed" and "Got Teredo Adress: ...". Then on the "Trackers" tab, DHT, Local Peer Discovery and Peer Exchange are all listed "working". Also, bt.connect_speed is set at 7 but net.max_halfopen is 100. I'm going to change that now. Dropping that to 8 didn't make it any better. I don't recall having ever changed the Advanced settings, and when I changed it, it looks like: "*8", with the asterisk, minus the quotes. The only setting I see that says uTP is "Enable bandwidth management [uTP]", which is checked (everything in Basic BitTorrent Features is but Limit local peer bandwidth), but I'm not sure on the Resolve IPs setting. One answer I read somewhere said to force outgoing protocol encryption, and dis-allow legacy connections, should the problem be ISP throttling. I've left those settings as such, but the change did not help me. Hope that helps you help me, and thank you.

One last thing. I temporarily rolled back to 2.0.2 just in case, but it had the same problem.

[Switeck]

I would expect uTorrent v2.0.2 to be worse instead of better, what with it using more UDP packets at the same speed as v2.0.3. v2.0.4 is out now, so give it a try.

Also, check your router logs. Others have reported their routers blocking uTorrent traffic and having internet problems because of it...though I don't recall LAN problems.

Does your router have stateful packet inspection (also called hardware firewall)? This can become overloaded by uTorrent if either the router is underpowered or the router is overheating.

The problems could be caused by something other than the router. If you're using wireless LAN, that can be local interference.

[powblock88]

Switched to 2.0.4, then kicked my Connections settings (Max/per torrent) from 300/10 to 300/30. Same problem, LAN Network Utilization spikes every 10 or so seconds, while torrent and browser speeds falter. Tried disabling the SPI Firewall as well, but that too had problems at the higher connection settings. Everything is at or below the uTorrent Setup Guide recommendations, and I've the green "Network OK" check on the bottom of the window. Router doesn't produce logs that I can tell, but UPnP is working fine showing up as being properly forwarded. I'm on an ethernet connection, so it's not that, unless you mean to say other wireless devices connected to the router are causing the problem. Overheating shouldn't be an issue either, as the weather's been mild, and there's plenty of air circulation around it.

[Switeck]

Disable UPnP, NAT-PMP, uTP Connections (Bandwidth Management), and IPv6 (in advanced settings) in uTorrent as well and please retest.

While testing, leave the SPI Firewall (on your router/modem?) disabled.

Are you using QoS features on your router to handle bandwidth traffic? (This would cause the router a big cpu load and might explain the spikey LAN traffic.)

[powblock88]

On my router, I've disabled the SPI Firewall, UPnP, and QoS. Then in uTorrent, I've unchecked UPnP, NAT-PMP, Apply rate limit to uTP connections, and Enable bandwidth management [uTP]; net.disable_ipv6 though was already set to true (I assume that means that it is disabled). Once everything was set thusly, I kicked my torrent connections back up to 30, and what do you know, it's working!

So I started re-enabling features one by one, starting with my router settings, and then moving on to uTorrent's. I quickly found out that re-enabling UPnP on my router caused the problem to re-manifest itself. Leaving it disabled, I continued to re-enable the SPI Firewall and QoS with no problems. Turning now to uTorrent, I re-checked UPnP, NAT-PMP, Apply rate limit to uTP connections, and Enable bandwidth management [uTP], and was still sitting pretty. So I then set net.max_halfopen back to 100 as well as my connection settings back to the uTorrent Setup Guide recommendation of 500/100. Still all clear.

How odd, that I've never had issue with UPnP in the past with any number of other torrents. Earlier, when I was disabling features, I had thought that I'd hard set the port forwarding to compensate for the fact that UPnP was disabled, but when I went back, I found that I'd just entered in the numbers and not applied the "enable" check box. Doing so, however once again caused the problem to appear, so I promptly cleared those settings and the problem vanished along with it. This too is strange, as I'm almost positive that when I first received this router, not forwarding the ports was what was giving me connection problems (different ones); who knows. Any clues as to why the port forwarding rules and UPnP were causing the traffic spikes? Thank you for the help, I'm glad we were able to get it working.

[Switeck]

"So I then set net.max_halfopen back to 100"

No real gain (basically means retrying dead ips faster) and it reduces your upload speed some to set it high. Try with net.max_halfopen set to only 8-20 unless you have 100's of started torrents. Incoming, uTP, and already fully connected connections aren't counted against the limit...so it's also not needed to be very high if uTorrent is getting incoming connections.

UPnP may be causing problems because uTorrent *NOW* uses uTP peer/seed connections heavily...these are UDP-based rather than standard peer/seed connections which use TCP. The router's handling of UPnP forwarding of UDP could be different than TCP and...a particularly heavy router cpu burden, causing LAN traffic speeds to sag/spike at regular intervals.

[powblock88]

Alright, good to know. I'll drop it back down again. I'd only pushed it back up, cause that was it's default value, but since I'm not running 100's of torrents simultaneously, then I guess there's no need for it. Thanks for the info about why UPnP was choking, and for helping me resolve this issue.