NetGong is a sophisticated network monitoring tool that allows network administrators, webmasters, and Internet service providers to monitor any networked device on the Internet, corporate intranet, or TCP/IP LAN and receive alerts immediately via audible alarm, message, e-mail, or third-party software when a connection fails. It is a shareware network monitoring application that's easy-to-use and efficient.
Here are some screenshots to illustrate the features and user interface of this application:
NetLimiter
Network Monitor II
Network LookOut Administrator Pro
OpenVPN GUI
Psiphon 3