tracepath, tracepath6 – traces path to a network host discovering MTU along this path

tracepath destination [ port]

It traces path to destination discovering MTU along this path. It uses UDP port port or some random port. It is similar to traceroute, only does not not require superuser privileges and has no fancy options.

tracepath6 is good replacement for traceroute6 and classic example of application of Linux error queues. The situation with tracepath is worse, because commercial IP routers do not return enough information in icmp error messages. Probably, it will change, when they will be updated. For now it uses Van Jacobson’s trick, sweeping a range of UDP ports to maintain trace history.