Table of Contents Traceroute ICMP mode UDP mode TCP mode Output format explanation Hping3 InTrace Nmap: traceroute-geolocation script Traceroute Traceroute is useful for diagnosing networking problems, e.g., end-to-end connectivty, complement with ping. It can also be used to pinpoint the location of devices, routers and firewalls. The tracerouting tools fundamentally rely on the IP packet’s field - TTL (Time-To-Live, decremented at each hop, dies at 0), they send short-life IP packets and wait for Time Exceeded ICMP packets reporting the death of these packets from a router, consequently reveal the route.