> traceroute a.b.c.d > traceroute 127.0.0.1 > That should tell you exactly where the packets are going. But it only tells you the IP hops. It doesn't indicate anything about the flow of the packets through the IP stack of the OS. In this hypothetical we know that both a.b.c.d and 127.0.0.1 are local. There will be only one hop.