Tool for traffic measure?

[David Kelly]

On Jan 2, 2009, at 11:21 PM, Sdävtaker wrote:

> Hello,
> I got a subnet with 5 machines and a cablemodem who provides 5  
> public ips
> All is conected to a switch.
> One of the machines is not ours and we want to check it is not
> abuseing our internet link, so we want to know if there is any way to
> monitor bandwich usage from one of the other machines in the subnet
> with no need to modify the foreing machine config. Something like use
> tcpdump in promiscuos mode or something like that, we doesnt matter
> the content, we just need a bandwich conssumption meassure.
> Thanks for any ideas.

Buy a smarter switch and do the traffic counts in the switch.

As things stand the switch is isolating all 5 machines from each  
other, none hear what the others have to say to the cable modem, so  
there is no way you can sniff the other's traffic.

If instead of a switch you had a dumb hub then all machines would  
hear what all the other machines were saying to each other and the  
cable modem. Is very hard to buy a dumb hub these days. Is easier to  
buy a smarter switch. A configurable smart switch can deliver the  
questionable machine's traffic to both the cable modem and to one of  
your machines but there is no point unless you want/need to see the  
contents of the packets. A switch that smart should also be able to  
count packets and tally total byte counts. If I understand correctly  
that is all you want.

--
David Kelly N4HHE, dkelly at HiWAAY.net
========================================================================
Whom computers would destroy, they must first drive mad.