HOWTO : Passive mode for Pure-FTPd

Step 1 :

sudo echo "50000 50100" > /etc/pure-ftpd/conf/PassivePortRange   
#real IP 192.168.50.100
sudo echo "192.168.50.100" > /etc/pure-ftpd/conf/ForcePassiveIP

Step 2 :

Restart the service.

sudo /etc/init.d/pure-ftpd restart