If you’re sending data to a partner via FTP, you don’t need an FTP port in Integration Server. An FTP port in Integration Server is to receive data via FTP. For sending, use the services in pub.client.ftp. Also, be very certain that the data being sent is not sensitive – FTP in no way is secure unless you’re using FTPS.
For learning new things, I find the SAG wM documents helpful in most cases. The docs describe how to define an FTP port, if you ever have a need to define one. 
[ Edit ] : I overlooked the TN aspect. Glad @Holger_von_Thomsen was paying closer attention than I was. 
#webMethods