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?
If there is a firewall between the client and the server (which there should be), then no, the server will not respond.
The VPN jumps the firewall. When you set up the VPN service, you created firewall rules to allow the VPN traffic. Then when you have the VPN connected, all traffic to the destination network is tunneled through that one connection.