iptables and pasv ftp

iptables and pasv ftp

[Denis]

Hi

I'm new to iptable-firewalling and hope someone is able to give some advice.
I'm using redhat 8.0 with
proftpd as ftp server and iptables as firewall. I wrote a rule in iptables
to open port
21. So connecting to my ftp server via active mode works just fine. But if a
client which itself lies behind a firewall tries to use pasv mode, the
connection doesn't work.
I guess I need to put in a new iptable rule or something, because if I
shutdown iptables pasv also works. I read that I need to open port 20 and
some ports like 64500:65535, and that I need to use ip_conntrack and
ip_conntrack_ftp?
Maybe someone has a HowTo?

Thanks

Denis J.