Free network monitoring utility software for windows

Qt Network Monitor is built in C++ and uses the underlying library libpcap / WinPcap to gather information about the network traffic. The GUI is built in QT and faily independent from the implementation of the device listener.
Qt Network Monitor is a open source bandwidth monitor written using Qt and LibScp/WinScp. Works well under Linux too though you have to compile it yourself.The application allows to monitor a device. You start the program, chose a device and put the application to the tray. You can then know how much bandwidth you are taking at any time.

Network Bandwidth Monitor 1 is considered as a convenient as well as effective gadget which shows in your Vista Sidebar or desktop your current network bandwidth.

Requirements: Windows Vista

Display all kind of information in real time about all network adapters Network Monitor application was designed to display all kind of information in real time about all network adapters (network cards, RAS connections, virtual cards, server monitoring for web hosting) in your system.
Network Monitor displays for each network adapter: download speed, upload speed, data transfered, IP address, MTU size, adapter type, MAC address, status and many more.

Connection Monitor 1.0 is a utility for you to monitor incoming and outgoing network connections. This is ideal for those whose computer is part of a local network or is accessible over an internet connection, as you can keep track of all wanted and unwanted outbound and inbound Socket-Connections on your computer monitor.