I've got troubles configuring an Hardware load-Balancer with NAT functions.
I have the following architecture:
Internet ===> VIP (public) LB (private ip) ====> private addressed servers
When a connection is initialised from the outside (internet) , the LB correctly forwards the SYN packet to one of the private servers. But when these servers want to reply with a SYN/ACK there is a problem.
the initial SYN packet had as ip header : VIP => Private_server_Address
But the private servers cannot reach VIP from their side (this is normal since it's nated), and then provide a correct reply.
Have you guys any solution to correctly forward the packets to their correct destination ?
Note: The load balancer, which is the default gw for the servers, also has a NAT rule for "masquerading" (actually more SNAT than real masquerading)