FTP/SSL

Is there any way to do connection tracking for incoming connections to an FTP/SSL server? I'm using a Bering (leaf.sourceforge.net) mini-distro that uses the Shorewall firewall (www.shorewall.net).

My firewall has both ip_net_ftp and ip_conntack_ftp, but as we all know, these don't work for FTP/SSL.

I am attempting to port-forward the FTP/SSL connection from the firewall machine to a server in a service network. The "command" connection on port 21 works just great, but when I try to GET, PUT, or LS a file, basically anything that uses the data connection, the firewall blocks the connection. It appears that FTP/SSL uses a high port -> high port connection for the data connection.

One possible solution (which I don't like!) is to open a large range of high ports in the firewall. This seems a bit primitive. There must be a way to associate the initial port 21 connection with the subsequent high-port connection.

Thanks for your help,

Sean