Right, but it’s not a matter of just adding firewall rules, it’s a matter of making the peer connection, right? If your server is v6 only (as a public), then your v4 only client can’t connect to it directly because, well, it can’t resolve the v6 public address.

The v6 server is (presumably) using some sort of tunnel to actually access v4 traffic, so it’s going to be able to reach an external v4 address. Which would be great, except that you don’t know what the public IP of your hotel is going to be before you get there.

To put the problem succinctly, if I’m at a hotel and I only have IPv4 access, and my home router only has an external IP address of a21b:b6f0:e9ec:9d11:5c48:7c4c:1054:2e32, how do I build a wireguard client config to connect back to that server?

All of the overlay networks (Nebula, Zerotier, Tailscale) kind of inadvertently solve that problem, though in different ways.

1 Like