How to enable Passive FTP for FTP server and with firewall
If you running a FTP server either Pureftp or Proftp in your linux server, it’s necessary and important to enable passive mode, because passive mode, works for ftp clients protected by firewall since the client initiates the connection.

You have to edit your Pureftp or Proftp configuration file and Add Passive Port range 30000-350000

Quote:
#vi /etc/pure-ftpd.conf

PassivePortRange 30000 35000
OR


Quote:
#vi /etc/proftpd.conf

PassivePortRange 30000 35000

Then in your CSF firewall configuration file under TCP_IN Allow incoming TCP ports 30000 – 35000

Quote:

vi /etc/csf/csf.conf

# Allow incoming TCP ports
TCP_IN = "20,21,22,25,53,80,110,30000:35000"
If csf is not there you can enable it using iptables

Quote:
iptables -A INPUT -p tcp --dport 30000:35000 -j ACCEPT

restart firewall and ftp server.

service csf restart
service pureftpd restart