Modifying received FTP messages
I am using a Fedora 3 linux machine (baby) as a simulation of a data translation computer (DTS). I have an ftp server running on baby, Computer A (Sarge) ftp's into baby, sarge then attempts to navigate through babies directories inorder to upload and download files. The problem arises when Sarge trys to jump through babies directory structure, the DTS unsderstands "cd CARD1" while baby requires "cd /user/CARD1", Sarge is set in his ways and cannot be taught new things.
Is there a way to modify received FTP packets (add correct syntax) before the commands are passed to babies OS?
I have attempted to translate the received 'cd' commands on the backend of babies ftp server via alias's, environment variables and symbolic links, all to no avail. I have looked into netcat but I fail to see how it will help. Any ideas?