The idea behind this project (NTAL) is to create a powerful tool for playing around with network traffic. The basic concepts are simplicity and flexibility. Instead of building tool that does something specific (and does a good job at it), we're trying to build a tool that will be able to do whatever you want it to do. To put it very simply, you write a script that will be invoked for every packet that passes through your network. You write your scripts in a TCL, fully blown, interpreted programming language. That fact guaranties that you won't be constrained in your creativity.
