Most FTP clients attempt to use passive FTP by default. Passive FTP is not enabled on ProFTPD. Fortunately, enabling it is very simple. Edit /etc/proftpd.conf and add ‘PassivePorts <low port> <high port>’ to the first section (global), then restart ProFTPD. You should use a really high port range to avoid conflicts. For example, you might want to add:
‘PassivePorts 63121 63129’
The number of ports needed is determined by the number of simultaneous FTP clients you expect to have.
If you are running a firewall, you may need to allow these ports in to your server. This will depend on the firewall – some will view this traffic as related, some will not.
