For some reason I wish to connect the WAN port and the LAN port on a router to the same hub and make the hub is connected to both networks, the Internet and a private network. Below is a diagram of the network configuration I'd like to build.

I tried this and it didn't work as expected. PC 1 has no problem, but PC 2 cannot connect to the Internet. When I ping 192.168.0.1 from PC 2, all packets are lost. It works well when PC 2 is connected directly to the router.
What's the problem with the network configuration above?
arp -aon PC 2 and see if the MAC corresponding to 192.168.0.1 is your router's MAC. There could be another 192.168.0.1 on the internet side. – billc.cn Nov 17 '12 at 18:37