No, it won't. All that's needed is an inbound route to your router, and NAT can't prevent that route from existing. It doesn't matter if you have ISP control or

No, it won't. All that's needed is an inbound route to your router, and NAT can't prevent that route from existing. It doesn't matter if you have ISP control or not. I'm not seeing any gre packets from you. Are you having trouble getting the tunnel working?