TORRENT blocking my internet connection

Question

I have a problem on my computer. If I open a torrent the download starts and after a few moments it goes back to 0. Then I lose all connectivity, Windows says there's no Internet connection and the only way to get it back is have to reboot the computer/modem. Once I do that everything works fine unless i start downloading a torrent.

What I tested:

It's not the client, it happens with old and new utorrent clients and deluga. It's not the router, all other computers on the network have Internet normally, while I go offline.

This is not a case of low speed because the torrent suck up the connection. Both the torrent and navigation stops and Windows 10 network center says no internet connection, disabling/reenabling the network has no effect, only reboot fixes it.

Any ideas?

Solution 1

This is usually caused by routers that do not have sufficient memory for the simultaneous connections that are running. You are most likely overloading your routers nat/state table.

1. Try going into your torrent programs advanced settings, dial the concurrent connection settings back till you stop experiencing the issue.

2. Upgrade your router to one that has more memory (ram not flash space). You can also try updating the firmware, it may just be a bug that's not allowing that nat table to clear old connections.

3. Check your cable modem logs, the cable modem can be reached at 192.168.100.1, looking for T3 dropouts and any other time out based errors. They can be resolved by Comcast at the street level.

Solution 2

Don't jump to the conclusion that your ISP is blocking that traffic, in my case my router was blocking me. I just saw that my router was blocking my computer as part of the DoS Protection.

When I looked at the blocked DOS Host list, my PC's internal IP was added to that list. So I cleared that and disabled the Dos Protection function.

Here is a screenshot from the router:

Comments

[Jeff Zeitlin]

Does your IP address change after the reboot? Does your ISP have any sort of prohibition on torrenting? Is it your router, or your ISP's, and are you getting "public" IP addresses, or do they start with 192.168._anything_ or 10._anything_? There's a whole lot more research that you have to do, and more information that you need to provide, before you can get any useful help here.

[Yorik]

I had problems in the past with a Comcast modem/router combo blocking or shutting down an ethernet LAN port for unknown reasons. As this was the port my secondary hub/switch was connected to, most of my LAN lost access beyond the switch as well. My one device connected to a second LAN port of the comcast device was had connectivity to the internet but could not get to anything on the switch. I did not have a torrent client. I suspected it was parental control or firewall related but never quite resolved it. This sounds like a similar problem.

[Yorik]

Note that some of their firewall settings had obvious bugs (block external pings allowed external pings, but blocked internal pings etc), so I presumed there was some misconfiguration causing this.

[Tim_Stewart]

Go to a browser, enter 192.168.100.1, this will bring you to the Comcast modem diagnostics page. Go to the log section, are there any items in the log that say "T3 dropout" or any "T" based errors?

[headkase]

I second the maximum number of concurrent connections. Years ago I had the same problem and my torrent client's number of connections turned out to be the culprit.

[tvdo]

It's not just memory (RAM); routers will often have a fixed limit to the NAT table, especially if they offload it to a hardware implementation. Unfortunately, it's difficult to find out what this limit is, but I've seen it range from 100 (!!!) to >1000. A torrent client can easily exceed those limits, especially if you have many popular torrents (e.g. a mainstream Linux distro) going at once. Some of them are listed here: bc.whirlpool.net.au/bc/hardware. Good call on limiting max concurrent on the torrent client.