At the minute I have all my machines connect directly to my isp-supplied broadband router. I want to make sure my machines are behaving correctly so I wish to test this by sniffing the traffic of each. How do I set up a linux box I have that has 2 network adapters, one ethernet one wireless, to act as (invisible) proxy to the network for another box connected to it via the ethernet port?
So in effect I want my proxy box to look after the DNS, HTTP and whatever ethernet multicast requests are normally serviced by the router. I have wireshark setup on my proxy box to sniff the traffic that comes through it's ethernet adapter, so I just need to know what I need to do to set it up as a fully-functioning proxy. The would-be proxy is Debian based.