Hello everyone,
    I have a firewall configured to forward port 80 traffic to an internal machine.  I was wondering if the same thing is possible with ftp traffic.  The rules I am using are as follows:

iptables -A PREROUTING -t nat -i EXTINF -p tcp -d 1.2.3.4 --dport 21 -j DNAT --to 192.168.2.5:21

iptables -A FORWARD -i EXTINF -p tcp -d 192.168.2.5 --dport 21 ACCEPT

iptables -A FORWARD -i EXTINF -o INTIF -p tcp --dport 21 -m state --state NEW,ESTABLISHED,RELATED -j ACCEPT

iptables -t nat -A PREROUTING -i EXTINF -p tcp --dport 21 -d 1.2.3.4 -j DNAT --to-destination 192.168.2.5:21

iptables -t nat -A POSTROUTING -o INTIF -p tcp --dport 21 -d 192.168.2.5 -j SNAT --to-source 192.168.2.254

I can connect to the ftp server but then I cannot establish a data channel between the client and the server. 

Any help would be appreciated.  If you want to see output of anything I can include it.

Thanks

Travis Crook
Visions Beyond