First, thanks to answer.
In the firewall, I only can access to the following chains :
I think, to redirect port, I have to access to the PRE_ROUTING chain ?
I try to put rules on the FORWARD chain such as :
* Destination IP : IP of the FTP server (188.8.131.52)
* INPUT : ETH01
* OUTPUT : ETH02
* PROTOCOLE matching : TCP (source port 21 , destination port 21)
I did the same with 20 port.
But, it didn’t work (with this rules). I can’t connect from outside.