MSR 1003-8 Opening a port range

[markagregory]

I have a MSR 1003-8 and I've placed a ftp server below it at 192.168.0.2 I've turned FTP/TLS on and forwarded ports 20 and 21 from the MSR 1003-8 to 192.168.0.2 I've been told that I need to permit traffic coming to the MSR 1003-8 on passive ports 55536-56559 to be passed through to 192.168.0.2 after the ftp/tls connection starts. Can't work out how to do this. The ftp client (filezilla) can connect to the ftp server but does not get the directory listing, which I'm told is due to the firewall. Would appreciate some help.