Source: University of California
Traceroute is the most widely used Internet diagnostic tool today. Network operators use it to help identify routing failures, poor performance, and router misconfigurations. Researchers use it to map the Internet, predict performance, geo-locate routers, and classify the performance of ISPs. However, trace-route has a fundamental limitation that affects all these applications: it does not provide reverse path information. Although various public trace-route servers across the Internet provide some visibility, no general method exists for determining a reverse path from an arbitrary destination.