ICMP-based network bandwidth measurement tool
Pure Java Network Tools
Hexadecimal and raw packet injector and sniffer.
Various TCP/IP servers, clients and network management tools
A simple packet sniffer for local networks
NetStress is a DDoS and network stress testing tool.
Send steganographed text messages to mtr with fake hops in the network
Simple Multi Protocol Packet Sniffer - SMPPS