Networking :: Iptables - Forward All FTP To Other Server?

So here is my issue in a nutshell. I need to take FTP requests that hit Server_A and forward them to Server_B. Server_B is not natted...Server_B is another public server in a completely different location in the world. One thing to note is that I only have one NIC hence why you will see both in and out being eth0. This is what I have in my iptables on SERVER_A:iptables -A FORWARD -p tcp -i eth0 --sport 21 -o eth0 -d SERVER_B --dport 21 -m state --state NEW -j ACCEPTiptables -A FORWARD -p tcp -i eth0 --sport 20 -o eth0 -d SERVER_B --dport 20 -m state --state NEW -j ACCEPTI've also tried both of the above without the --sport option. When I FTP to SERVER_A (where the above iptables rule are) it connects to SERVER_A instead of forwarding them to SERVER_B.