DNS Servers for AirVPN on Asus Router

[cfinley 3]

I am running AirVPN on an Asus router with AsusWRT-Merlin and I’m hoping someone can help me to understand the DNS server settings.

I have entered AirVPN's DNS 10.4.0.1 as first DNS IP address and, initially at least, I’ve tried to use an OpenNIC DNS for the secondary one. This has caused some problems as they seem to go offline quite frequently.

So, I thought I would try Cloudflare as the secondary, thinking it would be more reliable. The result has led me to question how public DNS servers work with AirVPN.

When I visit ipleak.net, “Your IP addresses” lists only the AirVPN exit IP address, while “DNS Address” lists both the AirVPN and Cloudflare ones. My understanding is that when the router is connected to the VPN, the Cloudflare server will act only as a failover DNS server when the DNS server of the AirVPN server can't reply, and that it will see any queries as coming from the AirVPN server exit IP address and not from my ISP’s IP address.

What confuses me is that Cloudflare is routing me through a server that is local to my actual location and not to the AirVPN server location, which is in another country. This leads me to think Cloudflare sees queries coming from my ISP’s IP address. Is this possible?

On a broader note: is Cloudflare a sensible choice for a public DNS server or are there better options?
 

[go558a83nk 364]

If in the openvpn config page you are selecting exclusive or preferred to the option to use VPN DNS then while connected to VPN the router automatically obeys the push message from the VPN server as to what DNS to use.  That'll override the DNS settings you enter in the WAN setup page.

[cfinley 3]

On 7/9/2021 at 8:38 AM, go558a83nk said:

If in the openvpn config page you are selecting exclusive or preferred to the option to use VPN DNS then while connected to VPN the router automatically obeys the push message from the VPN server as to what DNS to use.  That'll override the DNS settings you enter in the WAN setup page.

Thanks, go558a83nk.
I have changed the “Accept DNS Configuration” setting to “Exclusive”. The choices are Disabled, Relaxed, Strict, and Exclusive. It was set to the default, which is Relaxed.
Now, on ipleak.net, both “Your IP addresses” and “DNS Address” lists only the AirVPN exit IP address. I’m not sure I understand how this setting works but it seems to have done the trick.