traceroute / tracert

traceroute (on Linux and macOS) and tracert (on Windows) are diagnostic tools that map the path packets take from a source device to a destination, showing each hop along the route and the latency at each one. By sending packets with incrementally increasing TTL (Time to Live) values, they reveal every router the traffic passes through on its way to the target. This makes them invaluable for identifying where in the network a problem is occurring — whether a packet is being dropped, a specific hop has high latency, or traffic is taking an unexpected route.