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The moment I click "open" on the .torrent file, my router freezes, and I can't go says "connecting to" on the status bar.

And I can't access my router's control panel either!

Why does this happen, and is there any way I can download bittorrent?

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what router (make/model)? i assume when this happens you fix it by rebooting the router? – quack quixote Oct 6 '09 at 2:45
also, what bittorrent client (name & version) are you using? – quack quixote Oct 6 '09 at 2:46
Might seem petty, but you download VIA bittorrent, it's a protocol. Pet peeve, sorry :P – Phoshi Oct 6 '09 at 12:32
You're not "downloading Bittorrent"; you're "downloading a torrent". – endolith Nov 2 '09 at 15:01
up vote 10 down vote accepted

Bit torrent clients typically either saturate the upstream traffic of the internet connection or use up more connections that windows allows.

Try configuring your bit torrent software to have a maximum upload speed. I have a cable modem and I limit it to 20-40 KB/s, depending on what I'm doing on my computer otherwise. You'll have to fiddle with your settings to get it working correctly for you.

Be aware there are multiple factors you need to consider

  • the quality of your router (i found downloading many torrents would often cause my netgear router to overheat, so i kinda had to queue my torrents)
  • what other things you're using (listening to internet radio, watching hulu or youtube, VPN into work, etc etc) the more connections you have going on, the less there are available for BT. This applies to your whole home network, just not what you're doing on that one machine.
  • your windows configuration (hope many connections you're allowed to make, typically changed by messing the the registry... i personally try to stay away from doing this)
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I have 15Mbps up, 15Mbps down. – Alex Oct 6 '09 at 2:32
@Alex I would try limiting your upload speed to 20KB/s, which is pretty slow upload speed, and slowly raise it. Continue to surf the web and raising it until you find it un-usable. Then go down a few levels. This will give you a maximum amount of bandwidth for bit torrent while leaving room for your web browsing. Also, the time of day you do this is important too. – Roy Rico Oct 6 '09 at 2:42
Also note that some BitTorrent clients (like uTorrent) let you set time periods when your Torrent-ing is throttled down to a fairly low speed, and then ramp right up to full speed at others. This lets you set it to a low speed so it won't get in your way while you're surfing, and then go to full speed while you're in bed, asleep. Also it helps you get round the fact that some ISPs limit your speeds depending on how much peak-time usage you use, but don't care about your usage outside of peak time. – GAThrawn Oct 6 '09 at 11:02

This is most likely caused by using a cheapo no-name commodity router. These devices usually sell for 30-200$ in retail stores, and are made with the cheapest components their manufacturers can find, and the bare minimum of memory is installed in order to maximize profit per unit. While the speed of the traffic is not usually an issue for these devices, they are not designed to have large amounts of tcp/ip connections managed in their state tables, which is inherently caused by the bit torrent protocol.

If you are doing serious downloading I recommend using a dedicated older pc and pfSense as a router/firewall, which will guarantee rock solid connections, as well as it comes with a variety of other benefits such as bandwidth monitoring, proxy/caching, really easy yet powerful firewall, and more.

If this is not possible, try using a custom firmware on your router, or purchase a router that supports tomatoe or dd-wrt.

Last but not least, you can pick up a Cisco 830 series router for relatively cheap on craigslist or ebay. While moderately difficult to configure, these are also VERY solid devices.

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Could you recommend a similar router that could handle torrents well, but also has Wireless N? – deweydb Apr 10 '13 at 9:59

Aside from what's been said above, there is another glaring possibility: buggy router firmware, that's crashing on some packet that is rarely seen outside of P2P protocols. Try upgrading the firmware. If not, replace the router with a better one. Drayteks are pretty good as SOHO routers go, but you'll pay for them.

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+1 spot on with my diagnosis too. question is a bit foggy on the subject, but if it's really happening right when he starts a torrent going, it's not likely to be a problem with upload limits or concurrent connections. – quack quixote Oct 6 '09 at 12:18
Yes, this could be it too. I've had to upgrade my firmware before, and it did help a little, but I also pushed my router too hard that even new firmware, and DD-WRT both still crashed. – Roy Rico Oct 6 '09 at 15:12

Try lowering the number of connections allowed for your BitTorrent client, as well as previously mentioned lowering of upload speed. Unless you need the protocol encryption part, you can also try setting up QoS on your router, putting BT-packets as the lowest priority.

I've had problems with several routers of varying quality (some running dd-wrt or tomato), and this has made things slightly less unbearable.

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Tracking each connection via NAT, as well as TCP connections in general, use a small bit of RAM to keep track of state. With low-end home routers typically having 16MB of RAM, it's easy for them to run out of memory. – LawrenceC May 22 '12 at 2:36

Check your firewall settings on both the computer and the router. Also check to make sure that the ports you are using for bittorrent aren't blocked by anything. Possible some software somewhere is failing due to a contradiction of port blockage or contradicting policies.

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Bittorrent automatically adapts to blocked ports/NATs and while it may saturate your uplink, it shouldn't completely prevent other connections.

Does the bittorrent download start properly or does the router stop responding as soon as the .torrent file is downloaded? If it's the former, then limiting your upload speed from the bittorrent client should help.

If it's the latter, your router is trying to block bittorrent traffic. Try connecting an another computer to your network. If both computers' Internet connection freezes when you click on a .torrent file on one computer, the router is probably trying to do layer 7 filtering, fails to parse the traffic and freezes. In this case, downloading and installing a firmware update for the router should help.

If only the Internet connection for the computer that tried to download the .torrent freezes, then the filtering is working properly and you should be able to disable it from your router's settings. What is the make/model of your router?

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Check the maximum number of concurrent connections that your router supports: The router I use has an upper limit on the number of concurrent connections (255), so when I fired up Bittorrent for the first time (a few years ago), I couldn't use my phone anymore (voip).

Limiting the number of connections in my bittorrent client helped me there.

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