network monitor

Posted on 2005-05-16
Last Modified: 2013-12-07
Hi All,
 I have a very simple local network with one adsl router and 10 PC's, How can I know which one of the clients are making a heavy downloading, which slow the network?
 is there any dos command or network tool for this case?

Question by:deyaa
    LVL 95

    Expert Comment

    by:Lee W, MVP
    If you have a server you might be able to use Network Monitor (administrative tool) to identify the MAC address (but then you'd also need to have a hub and not a switch; most likely you have a switch.  Switches can do this too - if you have an EXPENSIVE managed switch, it's sometimes possible.  Otherwise, I can't think of an alternative right now.
    LVL 12

    Expert Comment

    any sniffer will do the trick, you can try ethereal, which is free software.  If your network is in a hub, then you can sniff all the traffic. If you are just in a non-managed switch, you will need to install a hub upstream of the switch (you can get a cheap hub for about 20 bucks these days) - plug the hub into the router, and the switch, and then plug your pc with sniffer installed into the hub as well. You can now sniff all the traffic and get an idea of what machine is doing what.

    Although, if it's just a small 10 PC network, you could just go to each machine, and run netstat -A (for windows) and get a list of all active network connections.

    LVL 1

    Expert Comment

    If all the PCs are directly connected to the router, my advice is: install a proxy server on one of the computers (or add a new computer to act as just a proxy, a simple PII will do it) and make all Internet traffic flow through it - this way you can impose limits. An easier solution might be installing a traffic monitor/filter like NetLimiter ( on each computer and use it to monitor the traffic flowing from/to each of them.
    LVL 79

    Expert Comment

    If you have a switch that is capable of letting you setup a mirror port, or monitoring port, you can download NTOP and let it run for a while. You'd be amazed at the information you can gather..
    LVL 79

    Accepted Solution

    Else, you can enable SNMP on every PC and monitor their network usage using MRTG/PRTG

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