lft - 3.8-2 main

This sends various TCP SYN and FIN probes (differing from Van Jacobson's
UDP-based method) utilizing the IP protocol "time to live" field and
attempts to elicit an ICMP TIME_EXCEEDED response from each gateway along
the path to some host.
lft also listens for various TCP and ICMP messages along the way to assist
network managers in ascertaining per-protocol heuristic routing information
and can optionally retrieve various information about the networks it
traverses.