I want to build a packet capture device for my home network (testing purposes). I have a spare computer with one NIC. I have CentOS. I've used TCPDump before so I plan on using that for now to see network traffic.
The issue is config. I have enabled IP forwarding: http://www.ducea.com/2006/08/01/how-to-enable-ip-forwarding-in-linux/
Now seeing I do have a modem/router combo (from ATT), I would rather not deal with that aka thats why I'm doing this project, how can I get ALL NETWORK traffic to pass through the packet capture device? NAT? Make it look like a router? If so, what are the iptable commands?
I believe this is the last part of my project, so any help would be great!