How to set DNS over TLS on Linux

Debian and most popular Linux distributions

For most modern Linux distributions, we recommend using systemd-resolved

Enable systemd-resolved

sudo systemctl enable --now systemd-resolved

Edit /etc/systemd/resolved.conf

sudo vim /etc/systemd/resolved.conf

Here's an example config:

/etc/systemd/resolved.conf

[Resolve]
DNS=185.222.222.222 45.11.45.11 2a09::#dot.sb 2a11::#dot.sb
DNSOverTLS=yes
DNSSEC=yes

/etc/systemd/resolved.conf

[Resolve]
DNS=185.222.222.222#dot.sb 45.11.45.11#dot.sb 2a09::#dot.sb 2a11::#dot.sb
DNSOverTLS=yes
DNSSEC=yes

Restart systemd-resolved

sudo systemctl restart systemd-resolved

Edit /etc/resolv.conf

sudo vim /etc/resolv.conf

Set nameserver to `127.0.0.53`

/etc/resolv.conf

nameserver 127.0.0.53

Test if DNS is working

root@server ~ # dig example.com
; <<>> DiG 9.11.5-P4-5.1+deb10u5-Debian <<>> example.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 63006
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;example.com.			IN	A
;; ANSWER SECTION:
example.com.		3309	IN	A	93.184.216.34
;; Query time: 0 msec
;; SERVER: 127.0.0.53#53(127.0.0.53)
;; WHEN: Fri Jul 02 10:29:59 UTC 2021
;; MSG SIZE  rcvd: 56

We can see the resonse DNS server is 127.0.0.53#53(127.0.0.53), which is working fine.

Windows Introduction to DNS.SB DoH