This is what you need to do:
Port forwarding your machine with port 21 is not enough. That’s only the trigger port that establish the connection. After that vsftpd needs more ports to be opened and forwarded by your router in order to upload/download/get list of folders etc.
So, first look at /etc/vsftpd.conf for that:
My conf for example has this port range:
pasv_min_port=64000
pasv_max_port=64321
All you need to do is add the exact port range to your router, together with port 21, and you’ll be able to establish ftp connection from the internet
Regards
Andreas
