natting issue
 

hi
i need your help to resolve this problem:

Server1:
- SuSE linux Enterprise server 9
- has a public ip address (registered in the ISP dns as mx record), and works as firewall server for my network

Server2:
- SuSE linux Ent. server 9
- has a private ip in my network
- will work as mail antispam gateway (kaspersky antispam)


Server3:
- SuSE linux Ent. Server 9
- has a private ip in my network
- will work as internal mail server (postfix)

now which rules should i add to Server1 (The firewall) to receive mails from Server3(inetrnal mail server)

How are these 3 servers networked? Does traffic to server1 from server3 go through server2? What makes you think this is a natting issue (according to your description all the internal servers should be using the LAN IP addresses)?