Configuration profiles for DNS over HTTPS and DNS over TLS.

Check out the article for more info: paulmillr.com/posts/encrypted-dns/

To make settings work across all apps in iOS 14 & MacOS Big Sur, you’ll need to install configuration profile. This profile would tell operating system to use DOH / DOT. Note: it’s not enough to simply set server IPs in System Preferences — you need to install a profile.

On iOS, after installation, go to system Settings => General => Profile, select downloaded profile and click “Install” button.

To verify resolver IPs and hostnames, compare mobileconfig files to the following documentation.

• Alibaba https://www.alidns.com/faqs/#dns-safe
• AdGuard https://adguard.com/en/adguard-dns/overview.html#instruction
• Cloudflare https://developers.cloudflare.com/1.1.1.1/dns-over-https
• Google https://developers.google.com/speed/public-dns/docs/secure-transports
• OpenDNS https://support.opendns.com/hc/en-us/articles/360038086532

Internal workings of the profiles are described on developer.apple.com.