Kernel parameters for DNS configuration

You can use kernel arguments to enable DNS over TLS (DoT) at boot time and set DNS resolution behavior for your system.

rd.net.dns-resolve-mode

Defines how DNS servers from global configuration are used during resolution. The following modes are relevant for both kernel arguments and NetworkManager.conf global configuration:

exclusive
Uses only the DNS servers specified by kernel arguments or in NetworkManager.conf. Forbids fallback to DNS servers retrieved from connections. This mode is relevant only for dnsconfd plugin.
prefer
Forbids using DNS servers from connections for general queries unless the queries are subdomains of domains set by connection.
backup
Merges and uses DNS servers from both the global configuration and network connections for the same purposes.
rd.net.dns-servers

Configures the list of DNS servers to use. To define multiple DNS servers, set rd.net.dns multiple times:

rd.net.dns=dns+tls://<server_ip_1>#<dns_server_hostname_1> rd.net.dns=dns+tls://<server_ip_2>#<dns_server_hostname_2>

For example:

rd.net.dns=dns+tls://198.51.100.143#dot.dns.example.com rd.net.dns=dns+tls://203.0.113.1#dot.dns.example.net
rd.net.dns-backend
Specifies the back-end DNS resolver. When set to dnsconfd, the system uses dnsconfd as a local DNS cache configuration daemon.