Forward & NAT Rules

[rauphel]

Dear all,
Need all your help & advise on configuration guides for iptable. I am totally clueless.

I have the following requirements has to be in place by using CentOS as mediator/middle guy for some reason.


Requirement
1. 4 Servers have IP addresses.
2. All application requests from Server A with specific port (as given)towards Server B and Server C must be going through CentOS.
3. Server B and C are recognized CentOS IP address only when request initiated from Server A.
4. CentOS must be able to map the source IP of Server A and forward using its own IP towards Server B and C.
5. The application request response came back from Server B and Server C should also be in contacted with CentOS only.
6. CentOS again will delay the request back to Server A.

Enclosed the diagram for more details.