Say I have a public server with a service (email, web server, etc) that’s accessible through https://myservice.example.com, and I would like to restrict that service with a VPN. How do I do that?
I know how to setup a VPN. I know how to use some of the services through that VPN. But see, if I want to use that VPN, I connect my client to that VPN, then I get the subnet of that VPN, say 10.10.100.0, through which I can access the devices by address.
But I see some services offer things like https://myservice.example.com, and they only work when that VPN is connected. How does that work? Is it just some DNS setting at the domain level or there’s more to it?
Set myservice.example.com to an internal address like 10.10.100.x. Those addresses are not routable on the public internet. They can only be reached from a local network which the VPN tunnels you into.
If your VPN also supplies DNS to clients, can also add a private zone if its supported so nobody can resolve that internal address except those clients.