LFT (Layer Four Traceroute) version 3.0 released

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-filters (firewalls)

LFT is the all-in-one traceroute tool because it can launch a variety of different probes using ICMP, UDP, and TCP protocols, or the RFC1393 trace method. For example, rather than only launching UDP probes in an attempt to elicit ICMP "TTL exceeded" from hosts in the path, LFT can send TCP SYN or FIN probes to target arbitrary services.

Then, LFT listens for "TTL exceeded" messages, TCP RST (reset), and various other interesting heuristics from firewalls or other gateways in the path. LFT also distinguishes between TCP-based protocols (source and destination), which make its statistics slightly more realistic, and gives a savvy user the ability to trace protocol routes, not just layer-3 (IP) hops. With LFT’s verbose output, much can be discovered about a target network.