OT: Network bandwidth monitor

[Steve Repo]

On Fri, Jun 12, 2009 at 12:42 AM, Roberto Ragusa<mail at robertoragusa.it> wrote:
> Steve Repo wrote:
>> Hello,
>>
>> I have a network of  20 hosts and all of them are windows machines
>> except one Fedora 10 box. One of the machines is using all the
>> bandwidth and seem to be uploading  something.  We have a liberal
>> network policy and policing the firewall is beyond my hands.
>>
>> What i'd like to do  is identify this rogue machine that is uploading
>> something and using our bandwidth.  I thought I could identify the box
>> that is using up the most network bandwidth.  Oh, we all machines are
>> on DHCP.
>>
>> Should I install iftop and run it on the fedora box?  or do i have to
>> make fedora as the router to capture all traffic? Any other tools that
>> does bandwidth monitoring?
>
> Excuse me if what I'm going to say sounds too stupid, but...
> could you have a look at the LEDs behind the machines?
> could you have a look at the LEDs on your network switch?
> could you unplug each machine for a few seconds and see if
> the traffic slows down?
>
> Because it is not easy to observe the traffic on your Fedora box;
> if the network is switched you have to rearrange things
> so the traffic actually goes to the Fedora box, as you
> already noted yourself.
>
> If the used bandwidth is really huge, the involved machine
> could be slower in responding to pings.
> Try pinging them all and see if one of them is remarkably slower.
> You can ping them one by one or all together (option -b).
>

Thanks for all the suggestions. We found the culprit by watching LED's
on NIC cards during off hours! It may have sounded a silly idea .. but
it worked!

Steve