netifera

Netifera another excellent Eclipse RCP based application.
Netifera is a new modular open source platform for creating network security tools. This project provides many advantages for both security developers and researchers who want to implement new tools as well as the community of users of these tools. It is available for Linux and Mac. Based on Eclipse RCP a Windows version sholdn't require a big effort, in their blog the netifera team says a Windows version will be available. I tested the Linux version in Ubuntu and works great.
To learn more about it see netifera screenshots watch the netifera video