DNS Leak over OpenVPN

Installing and Using OpenWrt
1 
iPhone Personal Hotspot via WiFi 
(ISP)

OpenWrt 22.03.2 
(WiFi Client and OpenVPN Client)

OpenVPN Access Server 2.8.5
(client internet traffic thru VPN, clients use specific DNS servers 1.1.1.1)

Where's the leak coming from? OS or App? Which host?
Doesn't DNS request normally get routed over VPN?

TIA!
XMAS

2

Interface for OpenVPN in OpenWrt
(Use DNS servers advertised by peer disabled)
(Use custom DNS servers 1.1.1.1/1.0.0.1)
Reboot

DNS Leak test failed

Shouldn't this have overriden the client.ovpn?

3

There's very little information to provide decent feedback.

You may want to post the following files from the /etc/config/ directory of your router, redacting any personal information:

  • dhcp
  • firewall
  • network

Add your .ovpn file and describe in as much detail as humanly possible how are you testing for DNS leak and how the device you're testing fits in your network.

4

Solution

add
block-outside-dns
to the OVPN config file (/etc/openvpn/FILENAME.ovpn) you are using.

via LuCi->VPN->OpenVPN and click Edit for the OVPN config in use.

Given OpenVPN Access Server was configured to give clients DNS resolvers not sure where the bug is.