iperf3: A TCP, UDP, and SCTP network bandwidth measurement tool
ZMap is a fast single packet network scanner for network surveys
Cross-platform, C implementation of the IETF QUIC protocol
Communication framework for data-centric high-performance applications
nanomsg library
An universal TCP client.
Real Time Tcp/Ip Stack Library
FreeBSD Multi PPP daemon
Packet generator and packet editor for Windows, Linux, BSD, and macOS
Very fast network stress tool
Robust and flexible VPN network tunnelling
High capacity syslog data collection, filtering, and management.
Encrypted UDP based FTP with multicast
tcptrace analyzes packet tcp connections and provides analysis
A simple, portable port scanner
Simple software for port forwarding and routing w/o a hardware router
One of the most advanced DNS Proxy and DNS Firewall in one product.
Snare Enterprise: bit.ly/Snare-Trial
Xplico is a Network Forensic Analysis Tool (NFAT)
continuation of the famous proxychains project by netcreature