This is a tool that allows you to "Man-In-The-Middle" any TCP connection and then fiddle with data before it is forwarded along to the server (or vice versa).

To demonstrate, we can run a telnet connection through PFI headed to the Ascii Art Star Wars show at Blinkenlights. It will demonstrate that we can intercept and edit traffic after it leaves the telnet client and before it arrives at the server.

PFI also has a plugin that will allow you to quickly shim your code into the Man-In-The-Middle. All you have to do is write a simple python function that receives a string and returns a string, and PFI will wedge that function to automatically execute each time data is received. An example of this is in example_pfi_plugin.py. Then all you do is click the "Select a file to execute as traffic comes in." button on the bottom of the UI to select the file with your custom code in it. Easy-mode tcp Man-In-The-Middle ;-).