I have Debian 8, Virtualmin, Proftpd I set up an ftp account, and I can login and download from within the same server.
However from another IP, I cannot connect in non secure ftp on port 21 (I can with sftp (secured) on port 22)
When making this : nmap -p 21 ip.num.ber I used to get this result PORT STATE SERVICE 21/tcp filtered ftp
So I made a change in Virtualmin in FirewallD, added port 21 applied configuration and now I get PORT STATE SERVICE 21/tcp open ftp
I checked the user in not in blacklist, An there is nothing related to PAM related stuffs.
However I still cannot log in using Filezilla. I think it is related to the firewall, I read that something need to be done in routing the packets, I am new to networking. thank you for your help