Site to Site OpenVPN with all traffic routed to one Site

[Troniker]

Hello I have the following issue:

I've successfully build a site to site connection via openvpn. User pcs are located at site A (firewall A) the second firewall (firewall B) is located at our datacenter (site B). So my concern is to use the firewall at site B as default gateway for all traffic generated at site A. Target of this should be that all outgoing traffic shows up with the public IP from site B.

I tested routing traffic from remote clients to site A to get another sender IP, that worked without problems.

But how can i realize to get my traffic send out from Site B ?

Thanks in advance.