tracert

tracert (called traceroute on Unix-like systems) is a network diagnostic command that maps the route packets take from your computer to a destination host. It lists every intermediate router, or hop, along the way and reports how long each one takes to respond, giving a step-by-step picture of the path traffic follows across the internet.

How tracert works

tracert relies on a clever use of the TTL (time to live) field in each packet. It first sends a packet with a TTL of 1, so the first router decrements it to zero, discards the packet and returns an error message — revealing its address. Then it sends a packet with a TTL of 2 to reach the second router, then 3, and so on. By gradually increasing the TTL, tracert coaxes each router along the path into identifying itself, building the full list of hops and their round-trip times.

What tracert is used for

tracert is a first-line tool for diagnosing connectivity and performance problems. If a site is slow or unreachable, a trace shows where along the path latency spikes or packets stop, helping distinguish a problem on your network from one at your provider or the destination. Administrators use it to investigate routing issues when reaching a VPS or a service behind a reverse proxy, and to confirm that traffic is taking a sensible path. Because it often shows router hostnames resolved through DNS, a trace also hints at which networks and regions traffic crosses. Results should be read with care: some routers hide from traces or de-prioritise these packets, so a single slow or missing hop does not always indicate a real fault. Still, tracert remains an essential, universally available tool for understanding how DNS-resolved destinations are actually reached.