netcat - Netcat is a featured networking utility which reads and writes data across network connections...
Ping Meter Gadget - Customizable, graphical, semi-transparent ping (latency) meter.
PortMapper - Do you need to map a specific TCP or UDP port on your machine to another port on another machine?
NetTK - NetTK, Network Tool Kit, is an Open Source alternative for monitoring and troubleshooting your...
Komodia Relay - Free open source tool to perform TCP based session relay
Fping (open source) - fping is a program to send ICMP echo probes to network hosts, similar to ping, but much better performing when pinging multiple hosts.