[ns] Where is the Application/FTP code?

[NS]

Hi would anyone be able to let me know where the code for the
Application/FTP is as I would like to modify receive method. I want to do
this as I would like to be able to on receiving a packet, return a new
packet of a defined size, if anyone knows of an easier way please let me
know. The idea behind this to to simulate the traffic too and from a DNS
lookup node.

Thanks
Mark