Load balancing + NAT issue on BNT GBE 2-7 equipement

Hi guys,

I've got troubles configuring an Hardware load-Balancer with NAT functions.

I have the following architecture:

Internet =3D=3D=3D> VIP (public) [Load Balancer] (private ip) =3D=3D=3D=3D>=
 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 SYN packet coming in the private servers has as ip header : VIP =3D> =

Private_server_Address

The answer packet then logically has: Private_server_Address =3D> VIP ,  =

in its source =3D> dest ip header

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 back to the =

LB, and make it process them correctly ?

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)

Regards,

Cl=E9ment.

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