packet tracer

Packet analyzer with HTTP file capture and a neat Graphical Packets Mode. Free.

Detect and prevent emerging network intrusions with real-time traffic analysis and packet IP logging.

Perform port forwarding, packet routing, cloning, and many other networking functions.

Switch on a computer from a second one by sending a "Magic Packet".

hping is a command-line oriented TCP/IP packet assembler/analyzer

Packetyzer provides a Windows user interface for the well known Ethereal packet.

oriented TCP/IP packet assembler/analyzer

CPU is a Cost Per Unit calculator to assist in deciding product / packet value.

Sniffer80 is simple web sniffer and packet analyzer based on .NET technology.

UDP packet sender utility.