Hi,

I am trying to find a way to monitor the usage by individual IP addresses of a masqueraded NAT internet connection, using a 2 nic linux server box, like below:

[internet] ---- [adsl modem] ---- nic-1 [linux server box, using iptables] nic-2 ---- [internal lan]

The nic connected to the adsl modem is called 'outside' and the nic connected to the internal lan is called 'inside'.

So, tried 'tcpdump' and 'ethereal' but all I get is:
- information on the traffic from/to the internal lan IP addresses to the inside nic
- information on the traffic from/to the outside nic to the internet.

Thus, no information on which of the internal lan IP addresses is requesting which information from the internet.

Is there a way to get information on which internal lan IP address is making which external internet request? That is, is it possible to 'see' through the masqueraded linux server box?

Thanks and regards,

Geoff.

I am not at my router to experiment with but maybe IPtraf can work. Also filter the dump using the mac address of the nic may help as well.

Brian1