Install the package.
Disable any services bound to port 53
To see if any programs are using port 53, run:
$ ss -lp 'sport = :domain'
If the output contains more than the first line of column names, you need to disable whatever service is using port 53. You are ready to proceed once the above command outputs nothing more than the following line:
Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port
Change system DNS server
Change your system's DNS server to an address in the
listen = section of the configuration file. If you don't know what you're doing,
127.0.0.1 is recommended.
To test if your system's DNS works, type
nslookup www.google.com into the command line. Note that this will work before DNS-over-HTTPS is configured, assuming you had a DNS configuration before installing this.
The client configuration file is
/etc/dns-over-https/doh-client.conf by default
Select preferred upstream DNS server
To select a preferred DNS server, uncomment one of the profiles.
If your preferred server is not listed, you may use the following template in the
[[upstream.upstream_ietf]] url = "https://[IP or web address]/dns-query" weight = 20