TCPView - TCPView is a Windows program that will show you detailed listings of all TCP and UDP endpoints on...
Open Nettest - Open Nettest is a platform for collecting, processing and visualizing data related QoS and QoE.
Connections Viewer - Connections Viewer is a useful network software utility with the primary focus of listing (and managing) both UDP and TCP connections inside the host system.
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.
CurrPorts - CurrPorts displays the list of all currently opened TCP/IP and UDP ports on your local computer.
Ping Meter Gadget - Customizable, graphical, semi-transparent ping (latency) meter.