anchor.diff:              '';
             };
   
  +          configFile = mkOption {
  +            type = nullOr path;
  +            default = null;
  +            description = ''
  +              Kea DHCP-DDNS configuration as a path, see <link xlink:href="https://kea.readthedocs.io/en/kea-${package.version}/arm/ddns.html"/>.
  +
  +              Takes preference over <link linkend="opt-services.kea.dhcp-ddns.settings">settings</link>.
  +              Most users should prefer using <link linkend="opt-services.kea.dhcp-ddns.settings">settings</link> instead.
  +            '';
  +          };
  +
             settings = mkOption {
               type = format.type;
               default = null;
  
positive.code:   })
  
    (mkIf cfg.dhcp6.enable {
  
      environment.etc."kea/dhcp6-server.conf".source = dhcp6Config;
  
  
negative.code:   })
  
    (mkIf cfg.dhcp4.enable {
      assertions = [{
          assertion = xor (cfg.dhcp4.settings == null) (cfg.dhcp4.configFile == null);
          message = "Either services.kea.dhcp4.settings or services.kea.dhcp4.configFile must be set to a non-null value.";
      }];
  
      environment.etc."kea/dhcp4-server.conf".source = dhcp4Config;
  
  