iperf3: A TCP, UDP, and SCTP network bandwidth measurement tool
Cross-platform, C implementation of the IETF QUIC protocol
An universal TCP client.
FreeBSD Multi PPP daemon
Robust and flexible VPN network tunnelling
Encrypted UDP based FTP with multicast
One of the most advanced DNS Proxy and DNS Firewall in one product.
Snare Enterprise: bit.ly/Snare-Trial
Linux Server and Data-Center WAN Optimization
implementation based on the Richards Stevens book.
Pen is a load balancer for udp and tcp based protocols.
IPv4/IPv6 TCP Echo Server scaling to 100.000+ concurrent sessions