Detect bandwidth throttling?

July 12, 2008 8:59 PM

We suspect our ISP is shutting down our internet connection when we use a BitTorrent client and/or throttling bandwidth. Is there any way to detect this?

We have Comcast and I know about the legal stuff but wanted to be able to detect it ourselves.

posted by ao4047 to technology (14 comments total)

Detecting whether the link is down is very easy. Run a continuous "ping" job in a DOS box (I'm assuming Windows here) while you try to use your torrent client. (Pinging Google is a pretty good test.) Make sure the ping has a reasonably long timeout, and see if you lose pings while the torrent is running.

Detecting whether they've throttled bandwidth isn't so simple.
posted by Class Goat at 9:05 PM on July 12

You can use this test: http://broadband.mpi-sws.mpg.de/transparency/bttest.php

It'll tell you if your ISP is shaping/limiting BT traffic, within a reasonable degree of accuracy. The site explains the process very well, so you should read up, but I've run the test a few times on different machines and it seems stable and safe.
posted by chudmonkey at 9:07 PM on July 12 [3 favorites]

Detecting whether the link is down is very easy. Run a continuous "ping" job in a DOS box

Just type "ping www.google.com /t" in the windows "run" box.
posted by delmoi at 9:10 PM on July 12

Keep in mind that BitTorrent can often saturate computers and/or internet connections, which looks and feels a lot like ISP throttling.
posted by Jairus at 9:41 PM on July 12

Seconding Jairus. So many connections are opened by the torrent client that all other requests for access are essentially ignored. In fact, in some cases, the router or modem can overheat and stop working temporarily. I've seen this with a few different routers through my extensive torrenting history, and it could very strongly resemble a faulty connection.
posted by Phyltre at 9:48 PM on July 12

Comcast is sending fake RST packets to both your computer and those you're connected to in order to close bittorrent traffic connections, using sandvine deep packet inspection equipment - and beating basic torrent encryption.

Basically Comcast is specifically interfering with your traffic, regardless of it's content, as long as it's certain types of P2P such as bittorrent. These RST packets don't just affect bittorrent; there's plenty of examples where they've illegally interfered with all sorts of normal legal traffic from their users. They're already being sued in a class-action suit over this.


Your only real options are
a) leave comcast, and find a sane ISP
b) try to join the class action suit, and suck it up while it grinds through court
c) install linux, and setup the firewall to ignore RST packets for bittorrent. This is a rather advanced topic.
d) sign up to a private torrent friendly VPN like secureix or relakks or torrentfreedom, and tunnel all your torrent traffic in a strong encrypted VPN connection. No guarantee comcast won't start throttling VPNs too though.
posted by ArkhanJG at 9:58 PM on July 12 [2 favorites]

I have comcast and I thought they were doing this at first too. But what was actually happening was uTorrent (my client of choice) was oversaturationg our Linksys WRT54G v.5 router with connections, which killed it after a few minutes or up to a half hour after starting up utorrent. After I lowered the global connections to 100 and enabled QoS on my router (dd-wrt mini).

Do a google search for something like "utorrent kills connection" and you will find several other people in your situation.

Of course, it could be your comcast, but mine is working pretty well.
posted by evanrodge at 10:36 PM on July 12

Yeah, if your router is doing NAT or stateful firewalling (it probably is), then it has a limit on the number of simultaneous connections it can keep track of; torrenting is an easy way to hit that limit. (Or it could be your ISP, of course.)
posted by hattifattener at 10:51 PM on July 12

All ISPs use throttling and QoS. Thats why skype works when youre neighbor is downloading torrents 24/7. I was just playing with a comcast connection here in chicago and pulled a torrent at a steady 400-500 kB/s. Im not sure what they are doing or have done (perhaps only to seeders) but I wouldnt jump to conclusions. Have you checked your equipment? Tried throttling your upload speed to less than 50% of your true upload speed? Update the firmware on your box? Lower the amount of global connections? or any other torrent specific tweaks? It could be a simple technical problem.
posted by damn dirty ape at 11:00 PM on July 12

Wired's "Howto" has a page about the whole ISP - Bittorrent thing.


Azureus has a list of the bad ISPs. Is your ISP on the list ?
posted by Baud at 1:42 AM on July 13

1. Sign up for a good USENET feed that offers a web interface so you can download over port 80 (aka http--the port all "regular" web traffic goes over).

2. Laugh maniacally at Comcast's impotence.
posted by Civil_Disobedient at 5:37 AM on July 13 [1 favorite]

All you have to do to avoid Comcast traffic shaping is to use something like Tor for the client-to-tracker connection, and encrypting your headers. DO NOT USE TOR FOR TRAFFIC, THAT'S NOT WHAT I'M SAYING.

Proxying your computer to the tracker gets around (or at least USED to get around) their model and encrypting your headers obfuscates their method for looking at session initiation.

Changing the default port doesn't hurt, but it doesn't do as much as it used to.
posted by TomMelee at 2:19 PM on July 13

Does your problem persist after you stop using your torrent client? I'm asking because this just started happening to me the other night. I fired up uTorrent and was torrenting away, and then the connection went down and wouldn't come back. So I rebooted the modem and it worked again. Then the same thing happened and I did the same. Finally I gave up.

But now the connection periodically goes out even though I haven't used any torrent client since then. Comcast came out and replaced the wires but it didn't help - I still lose the connection and have to reboot the modem to get it back. I was wondering if this was some kind of interrupting tactic by Comcast. Or maybe bittorrent somehow put something on my computer that periodically kills the modem? Comcast said the modem was fine so I'm stumped.

If yours only has a problem during torrenting then I guess these are different issues.
posted by Askr at 8:10 AM on July 15

It sounds like a person upthread is saying that the ISPs are getting around encryption these days, but if you haven't already tried something like this, give it a shot. I also read something once that explained how to change some settings in uTorrent's options/settings/preferences/whatever menu to get around throttling but now I can't find it.
posted by Askr at 8:15 AM on July 15