Nethserver vsftp active mode

NethServer release 7.6.1810 (final)
Name : nethserver-vsftpd
Arch : noarch
Version : 1.1.1

Hi everyone, I need to activate the active mode of vsftp on neth server as the ftp connection requires tcp ports from 30000: 30999. The server is behind a firewall, so I would like to activate the standard tcp connection with port 21 and 20 for data transfer.
Thanks for any suggestions.