If you are running a FTP server (Pureftp/Proftp) with a CSF firewall (very important in a VPS or virtuozzo), it is necessary to enable passive mode, because this mode works best for ftp clients protected by firewall since the client initiates the connections. If you don’t enable passive mode in VPS, you might encounter problems like unresponsive ftp server or hang or it will not list the directories after FTP connection.
Here are the steps to enable passive FTP.
Login to your server using a SSH client
Open the Pure-FTPd configuration file in your favorite editor
# vi /etc/pure-ftpd.conf
Uncomment the line that starts with PassivePortRange and add:
PassivePortRange 30000 35000
Restart Pure-FTPd with the command,
# service pure-ftpd restart
If you use a firewall don’t forget to allow inbound connections on the newly added ports.
This can be done by editing CSF firewall,
# vi /etc/csf/csf.conf
and add th ports as below.
# Allow incoming TCP ports
TCP_IN = “20,21,22,25,53,80,110,30000:35000”
# service csf restart
# csf -r
# service pureftpd restart
Same steps can be followed for proftp as well, in proftpd.conf, you will have to edit the option “PassivePorts”.