Ftp server behind firewall

[Pierre Santana <gnuskiter@xxxxxxxxx>]

Hi;

I have a ftp server behind firewall and I can connect on ftp server
but I can't  list the archives of the directory.
The ftp server use the port 21 to connections and 20 to send packages.
How I can do the iptables rules?

Tank you.

--
  _
 ºVº    Pierre Santana
/(_)\   Linux User # 301047
 ^ ^    gnuskiter@xxxxxxxxx