LFT, short for Layer Four Traceroute, is a sort of 'traceroute' that often works much faster (than the commonly-used Van Jacobson method) and goes through many configurations of packet-filter based firewalls. More importantly, LFT implements numerous other features including AS number lookups, loose source routing, netblock name lookups, et al. Though LFT has been around since 1998, its development effort has just recently resumed.
