dnscrypt-proxy is an application for macOS that uses the DNSCrypt protocol to authenticate communication between your device and Quad9.
Step 1 - Install
Install the latest version of dnscrypt-proxy for macOS following these instructions: Installing dnscrypt-proxy on macOS
Step 2 - Configuration
Once you have dnyscrypt-proxy installed and working, you will then need to configure it to use Quad9's servers. To do this, you will need to edit the dnscrypt-prxy.toml file located in the dnscrypt-proxy folder. This file is automatically configured to pick working servers from a predefined list which contains Quad9 servers. To specify that you want to use Quad9, remove the # symbol from before server_names and enter a valid Quad9 server name.
Quad9's DNSCrypt server names can be found on our Quad9 IPs and Other Settings page.
Adding multiple Quad9 services is possible by simply comma separating the server names. Example:
server_names = ['quad9-dnscrypt-ip4-filter-pri', 'quad9-dnscrypt-ip6-filter-pri']
For more information on configuring dnscrypt-proxy for macOS: Configuring Sources