If you are using pure-ftpd, you need to edit /etc/pure-ftpd.conf and change the port below to something other than 21.
Code:
# IP address/port to listen to (default=all IP and port 21).
# Bind 127.0.0.1,21
If you are using protftpd, you need to edit/etc/proftpd.conf and change the port below to something other than 21:
Code:
Port 21
After making the change, you need to restart the FTP server to make the change live:
Code:
/scripts/restartsrv_ftpserver