With this command-line tool one could join tcp-packets and analyze them. Can be used as a portscanner, traceroute or remote OS fingerprinting. Besides tcp also udp, icmp and raw-ip supported.
PingPlotter Freeware is a high performance, low-overhead traceroute application. It allows you to quickly "trace" the route between you and a target of your choice (a web site, Voice over IP provider, online game server, or similar target), and then continue to collect performance metrics about that route.