One of my clients has a network that has a very poor internet performance (meaning the internet goes very slow).
I would like to see the internet traffic to determine whether the problem is situated with a saturated internet line or elsewhere. The problem is that the modem of the provider is inaccessible to me and the firewall behind it doesn't have a decent counter. Somebody suggested me of putting up a simple PC client between the firewall and the rest of the network and to install a software bandwidth monitor to see what goes through the internet line, but I never did this and don't know how to start with that. Or perhaps there is a better solution?
The network is basically setup like this:
ISP ADSL line > Cisco 800 ADSL modem/router > Netscreen firewall > switch