I wondered why I was asked twice about network troubleshooting between two machines and the destination machine is not reachable directly. It seems there are somethings I didn’t understand fully or I missed something. Today I googled "tracert is not enough" and found Traceroute Limitations Explained. It explains my doubts now. Traceroute Limitations Explained gives some limitations of traceroute and introduce their production to avoid those limitations. Are there any other ways?