OpenVPN client advanced config, like this screen shot.
On the server end, you can just have 1 OpenVPN server running, listening on LAN. Then port forward the port you want to listen on from WAN1, WAN2… to LAN. That way the same OpenVPN server receives the connect requests from the client, whichever public IP address the client connects to.
[image: OpenVPN-Client-Dual-Server.png]
[image: OpenVPN-Client-Dual-Server.png_thumb]