hping is a command-line oriented TCP/IP packet assembler/analyzer. The interface is inspired to the ping(8) unix command, but hping isn't only able to send ICMP echo requests. It supports TCP, UDP, ICMP and RAW-IP protocols, has a TraceRoute mode, the ability to send files Between a covered channel, and many other features.
While hping was mainly used as a security tool in the past, it can be used in many ways by people that don't care about security to test networks and hosts. A subset of the stuff you can do using hping:
Firewall testing
Advanced port scanning
Network testing, using different protocols, TOS, fragmentation
Manual path MTU discovery
Advanced traceroute, under all the supported protocols
Remote OS fingerprinting
Remote uptime guessing
TCP/IP stacks auditing
hping can also be useful to students that are learning TCP/IP.
