I am setting up a LAN with several servers and workstations. One of the servers is a DNS/DHCP server. All servers have static IPs and names, and workstations use DHCP. At the moment, everything works fine.
But now I am trying to access a 3rd party VPN (NordVPN). But when the VPN is connected on a server, the address for the DNS server doesn’t get changed to the VPN’s, which causes a DNS leak. I know that data is routed correctly to the VPN, but just not the DNS. I should mention that on a Windows machine, I can connect and the DNS get sets correctly to the VPN’s server. I have no idea at this point what to look at. Please, can someone help me with this?
It depends on what type of client is used to connect to the NordVPN. That upstream article about terminal only way is wrong in my opinion.
If you have the connection is configured by NetworkManager, you should reconfigure it in Network Manager. Use nmcli c edit or nmcli c modify instead. You will have to set ipv4.dns via nmcli to new values, followed by set ipv4.ignore-auto-dns yes. Then save & activate.
We cannot help with NordVPN client setting, if no more information is provided about it. I do not want to install it myself to help someone else. Do they provide at least systemd unit for connecting and disconnecting? Or even Network Manager connection visible in nmcli? In my opinion, you want to send DNS to them only when connected to the VPN. Otherwise you worse your privacy on trusted networks, because you relay all DNS queries NordVPN unconditionally to them. I don’t think you want that, but that is exactly what they recommend in linked article.