can't access ftp from clients

[Cosmas Panagiotis]

Hi, I’m using masquerading on a redhat 6.0 with a simple script:   ipchains –A forward –i ppp0 –j MASQ   Everything works well except that I can’t access any ftp site from clients (win9x), console ftp client reports “illegal port command - cant ’build data connection” on any request (e.g. ls –lr) although I’ve logged to remote ftp site. The same problem exists trying ftp from internet explorer via squid proxy (listens on 3128 port).   Is there a way to deny masquerading and forwarding only for ftp?   Cosmas Panagiotis