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!

  • use -j TEE target. ipset.netfilter.org/iptables-extensions.man.html – Ipor Sircer Feb 17 '17 at 17:50
  • Could you provide a example please. I'm not that familiar with iptables for NAT? – Benjamin Jones Feb 17 '17 at 21:07
  • After reading about TEE it sounds like it just forwards a packet to what you mention as a gateway (Dest). Not sure not that would help me? Would IP forwarding bring all traffic in and I would use TEE to forward it to the router/modem? – Benjamin Jones Feb 18 '17 at 5:08

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