On the top of the page the current status of the systems DNS is displayed.
This can be working or broken which means, the system is not able to do any name resolution and DNS is not working on the system and if you are using IPFire to serve the DNS for your network also.
Likewise a section of all currently configured and used DNS servers will be shown.
As usual a single entry can be enabled/disabled, modified or removed by using the corresponding tool in the action section next to it.
When using ISP-assigned DNS servers, they can not be modified here, please use the checkbox in the DNS Configuration section.
A new server easily can be added by using the "Add" button.
A list of free non-compromised DNS server can be found here.
Specify the IP address of your desired DNS server here. It has to be a valid IPv4 address.
This field requires the hostname details of the certificate, which the DNS server uses and is only required if you configured to use TLS for DNS queries. It must be given as a fully qualified domain name.
However it might be helpfull to specify the TLS hostname details, if you plan to switch to TLS at a later time.
The Remark field is optional.
When using this button, a short check for each enabled DNS server will be conducted and will display if your current settings are correct. Hovering the mouse pointer over the server's Status will provide additional debugging information (DNSSEC Validating, DNSSEC Aware, etc.).
If there are no (working) DNS servers configured, the system will go into recursor mode. In this mode, it will contact the root servers to resolve queries and recursively work its way down the DNS tree without using any third-party resolvers.