I have a satellite-connected modem for internet access: a (wifi+wire) router is connected to this, and provides access to a LAN with several Macs, 2 windows boxes, and an Ubuntu machine. Most connections are via wifi. One of the Macs on the network is a Mac Pro which has two NICs, only one of which is being used.
I would like to monitor download volume from the internet: ie what contributes to my download cap from my ISP. What's the best way of doing this?