hping

Command-line oriented TCP/IP packet assembler/analyzer

hping3 is a network tool able to send custom TCP/IP packets and to display target replies like ping do with ICMP replies. hping3 can handle fragmentation, and almost arbitrary packet size and content, using the command line interface. Since version 3, hping implements scripting capabilties, read the API.txt file under the /docs directory to know more about it. As a command line utility, hping is useful to test at many kind of networking devices like firewalls, routers, and so. It can be used as a traceroute alike program over all the supported protocols, firewalk usage, OS fingerprinting, port-scanner (see the --scan option introduced with hping3), TCP/IP stack auditing.