[soviel]

How do you make sure your pi-hole instance is only used by the rightful user? After all you can't restrict port 53, and I am sure iptables are not an option here since you don't know from where the users will be connecting?

[saimiam]

I want to know this too.

FD - I recently launched an adblock as a service (listed in my profile.)

Edit1 - maybe it's security through anonymity. Don't tell anyone your DNS server address?

[soviel]

I doubt it. People are specifically looking for open port 53. After reading a bit the pi-hole documentation, I found out they recommend pairing it with OpenVPN. https://github.com/pi-hole/pi-hole/wiki/Pi-hole---OpenVPN-se...

[saimiam]

If OP is using a vpn to route traffic, they should call it out.

Our adblocker uses a much less intrusive idea than VPN to block unauthorized IPs from hitting 53.