[SOLVED] Forwarding

[andras.babos]

Dear all,
I have the following situation.
I have an firewall in fornt of zimbra apliance.

I forward all request to port 25 to the zimbra apliance but zimbra doesen't respond.
Here the firewall rule.
-A PREROUTING -d RealIP -p tcp -m tcp --dport 25 -j DNAT --to-destination 192.168.0.111

-A POSTROUTING -s 192.168.0.111 -p tcp -m tcp --dport 25 -j SNAT --to-source RealIP
Where 192.168.0.111 is the ip of zimbra apliance.
If I send an telnet comand to ip 192.168.0.111 por 25 from local network (192.168.0.x) the zimbra apliance it's alive:
telnet 192.168.0.111 25

Trying 192.168.0.111...

Connected to 192.168.0.111.

Escape character is '^]'.

220 xyz.com ESMTP Postfix
I'm sure that the firewall it's ok because I use iperf to emulate port 25 to another host and it's work the firewall rule.
Can anyobdy explain me what I nett to change in main.cf postfix configuration file to work.
Thaks for support