In recent few months FTP brute force attacks increased on most the cPanel servers. To avoid such attacks, we can simple default FTP account or change FTP port. If you are shared server then client won’t be happy after disabling default FTP which is cPanel login details. There for simply change the FTP port number by using following steps.
Log in to server as root user and open default FTP configuration file.
server@root[~]pico /etc/pure-ftpd.conf
Search for following line and change it
From
#Bind 127.0.0.1,21
To
Bind 0.0.0.0,121
It means all ip will connect to FTP service on port 121 but make sure that you have opened a port 121 in server firewall and restart the FTP service.