How To Find Out What’s Eating The Bandwidth

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Is there a program that will tell me what’s eating the bandwidth on a lan?

I’m thinking of something that would tell me that a.b.c.d is using so many mbps and a.b.c.e is using this many and so on.

Or can just-another-computer-on-the-network actually see that sort of information? I don’t know enough about the low level nuts and bolts of networking to know if it has that kind of access. I’m really just interested in volume of traffic per attached device rather than specific origin/destination information if that’s easier to obtain.

This way if something is eating the network I can find out what it is without having to start unplugging cables and so on to find out when it stops.

6 thoughts on - How To Find Out What’s Eating The Bandwidth

  • It’s a really basic setup “routers from Staples” (dlink and tplink brands I think) plugged into the ISP’s modems.

    Then I’m outta luck for doing this sort of thing since the gateways are the tplink and dlink routers. I thought that might be the case.

    Thanks for the answers, guys! It isn’t what I wanted to hear, but now I know more about this than I did before.

  • There are two options you could explore:

    * putting openwrt or another open-source firmware on those devices, if they
    support them.

    * Use a CentOS (since that’s the list!) box with two NICs as a bridge and
    configure that for snooping.

    Or I guess option 3 would be to replace the routers with ones which do allow you use an open firmware. You could even do that temporarily just for the experiment.

    And finally, an option four: some router brands have their own proprietary bandwidth monitor tools. Asus, for example. (Note that you probably can’t get full gigabit speeds with this enabled on an off-the-shelf consumer router, though.)

  • If you want to keep your tplink and dlink devices, you might be able to get a managed switch for a few bucks via craigslist or ebay and plug the devices on the network into that. For the purpose, an (old) 10/100Mbit should do, though it’s certainly better to get a 1GB (or faster) one if you can find one for a good price.

    Just keep in mind that you may need to configure the switch before you can use it, which can involve using a serial cable with some models. You’d probably want one you don’t need that cable for.

    Such a switch will usually show you how much bandwidth is going over each port and makes this an easy task.