I want to set up a VPN that uses the client’s IP when sending data out of the VPN server. I am able to use either OpenVPN (open-source edition), or Wireguard.
IP spoofing on the internet won’t get you very far. So, no, this won’t work. I don’t even see a scenario where this would make sense.
Yeah, not sure how many isps block it. They didn’t used to 10 years or so ago. I used to block unknown ips at my egress.
But they should, and I’m hoping they do now.
I’m also not too sure what the point would be for the OP. Even if their isp allows the ip spoofing the response would take the normal route back to the vpn client.