Disclosed herein are systems, methods, and apparatus for performing a new kind of traceroute. This traceroute is referred to herein as a “reverse” traceroute, as it enables a given network node to determine the path of packets sent to it from another node. Preferably, an encapsulating tunnel between the two nodes is leveraged. Preferably, a given network node (“first node”) performs the reverse traceroute by sending encapsulated inner packets in the tunnel to another network node (“second node”). The second node reflects the inner packets back to the first node. Preferably, the inner packets are configured such that their IP header TTLs expire at intermediate nodes (such as routers), and such that the resulting error messages are reported to the first node. In this way, the first node obtains information about the topology of the network and the path taken by inbound packets.