I got proftpd on my debian (jessie). I used sudo apt-get install proftpd. It corrected it automatically to proftpd-basic. I did not care. When i set it up i opened port 21, port 2121, and port 2122(2121 and 2122 are listening ports). I used ftptest.net and it gives me this error(using port 21): Error: Server returned unroutable provate IP address in PASV reply
using port 2121 or 2122, i get a refused connection error.
So far, i dont know much about it. If u could to give me help, i would love it.