AlmaLinux OS 9 must configure a DNS processing mode set be Network Manager.

To ensure that DNS resolver settings are respected, a DNS mode in Network Manager must be configured.

Note: If AlmaLinux OS 9 is configured to use a DNS resolver other than Network Manager, the configuration must be documented and approved by the information system security officer (ISSO).

Verify that AlmaLinux OS 9 has a DNS mode configured in Network Manager.

$ NetworkManager --print-config [main] dns=none

If the "dns" key in the [main] section does not exist or is not set to "none" or "default", this is a finding.

Configure NetworkManager in AlmaLinux OS 9 to use a DNS mode.

In "/etc/NetworkManager/NetworkManager.conf" add the following line in the "[main]" section:

dns = none

NetworkManager must be reloaded for the change to take effect.

$ systemctl reload NetworkManager