Hello 
I have some problem with dns leaking. I am using my router only for a VPN server, OpenVPn in particualar. Everything works just fine, but when I do run some leak test on the various sites, there seems to be a problem with Google's DNS address. They always leak, and it seems that they are the default (8.8.8.8) DNS for the OpenVPn server on the router.

I don't have this problem when I run the test outside the VPN (local ISP), I am using pulic Cloudfare DNS -1.1.1.1 and 1.0.0.1. I have tried different ISP, put the router at friend of mine - still the same. No leakage of the ISP DNS servers, just google's. 

How can I change the DNS server for the VPN server (openvpn server at Archer)? You can see in the screenshots, that when setting the router, I am using 1.1.1.1 at all places. Also I use these DNS at my LAN adapter as well. One more questions: Is it possible to have access and editing the config.file of the openvpn itself?  I am using the setup with OpenVPN client Connect where I can edit only the config file of the client.