Victor Oppleman maintains the [http://pwhois.org/lft/ Layer Four Traceroute] and [http://pwhois.org/ Prefix WhoIs] tools. [http://pwhois.org/lft/ Layer Four Traceroute] is a modern replacement for traceroute that supports several layer-4 protocols (TCP, ICMP, UDP). LFT also has advanced options for path discovery (firewall detection, load balancer detection, etc) and for network and name resolution (Autonymous system numbers and network names).