For the interface question you need to find out what your ethernet adapter is called, it may be called eth0 or it may be called something different. ip addr show
may give you a better idea what your network adapter is called, just look for your known IP address.
As for the router issue, you can either change the IP address of the fog server or of the scope in your dhcp server. Changing the scope might be easier.
I had a long post here, but decided to be cautious first. Please post the output of ip addr show
first.