Changing OpenVPN to pass through pi-hole

Question

I have OpenVPN (setup via www.pivpn.io) on my Raspbian Jessie RPi3 working like a dream.
I now have setup "pi-hole" on a Pi Zero. Here's my current situation:

• If I am at home, I can use pizero's IP as DNS server and pi-hole works fine.
• If I'm away from home, I can connect to my "Pi3 OpenVPN".

What I want to do is to connect via VPN and make use of pi-hole at the same time.

I'm not very proficient in network configurations, but I believe this is simply a matter of changing the DNS server that OpenVPN is using from Google's to the PiZero's IP. How can I do this?

I have tried to run the pi-hole setup on the same Pi, but I couldn't make this setup work. That's why I'm now using 2 different machines for what could ideally be done in one.

Answer 1

While writing my question, I found my answer. What I did was add

dhcp-option DNS 192.168.1.56

to my .ovpn profile file. That's the IP of my pi zero. Works like a charm.

Another alternative (I think) would be to add the pi zero's IP address as the main DNS server of my home router, but I lack the administrator rights to do that.

edit:
aaand another option: https://openvpn.net/index.php/open-source/documentation/howto.html#dhcp
This shows how to push dns settings as a dhcp option to the clients, and is done in the /etc/openvpn/server.conf file.