@iroal ddns doesnt work if it is behind double NAT

@JaredBusch hello, i have done this but my mobile devices status says never, and it isnt coming online or even offline.
EDIT: reinstalling made it work on mobile data, now how did you route it to use pihole as dns, so that it can filter ads?

@scottalanmiller hello, i have Raspbian Stretch Lite,

my aim is to have pi running 24/7 working as pihole/ OpenVPN.
in which I successfully configured pihole and its working great in the entire home network, but I can't have OpenVPN as it requires ddns and port forwarding...

things I want to learn:

how zero tier will come in place?
how to configure it with OpenVPN?
is it possible to route it through double NAT internet connection that I have?