self-hosted Dns Over Https service

LibreOps & LibreDNS

LibreOps announced a new public service: LibreDNS, a new DoH/DoT (DNS over Https/DNS over TLS) free public service for people that want to bypass DNS restrictions and/or want to use TLS in their DNS queries. Firefox has already collaborated with Cloudflare for this case but I believe we can do better than using a centralized public service of a profit-company.

Personal Notes

So here are my personal notes for using LibreDNS in firefox


Open Preferences/Options
firefox options

Enable DoH
firefox doh

TRR mode 2

Now the tricky part.

TRR mode is 2 when you enable DoH. What does this mean?

2 is when firefox is trying to use DoH but if it fails (or timeout) then firefox will go back to ask your operating system’s DNS.

DoH is a URL, so the first time firefox needs to resolve doh.libredns.gr and it will ask your operating system for that.

host file

There is way to exclude doh.libredns.gr from DoH , and use your /etc/hosts file instead your local DNS and enable TRR mode to 3, which means you will ONLY use DoH service for DNS queries.

# grep doh.libredns.gr /etc/hosts doh.libredns.gr

TRR mode 3

and in



DNS Leak

Try DNS Leak Test to verify that your local ISP is NOT your firefox DNS



Thunderbird also supports DoH and here are my settings


PS: Do not forget, this is NOT a global change, just your firefox will ask libredns for any dns query.