anchor.diff:                # Invalidate the nscd cache whenever resolv.conf is
                 # regenerated.
                 libc_restart='${pkgs.systemd}/bin/systemctl try-restart --no-block nscd.service 2> /dev/null'
  -            '' + optionalString cfg.dnsSingleRequest ''
  -              # only send one DNS request at a time
  -              resolv_conf_options+=' single-request'
  -            '' + optionalString cfg.dnsExtensionMechanism ''
  -              # enable extension mechanisms for DNS
  -              resolv_conf_options+=' edns0'
  +            '' + optionalString ((stringLength resolvconfOptions) > 0) ''
  +              # Options as described in resolv.conf(5)
  +              resolv_conf_options='${resolvconfOptions}'
               '' + optionalString hasLocalResolver ''
                 # This hosts runs a full-blown DNS resolver.
                 name_servers='127.0.0.1'
  
positive.code:                    config.services.dnsmasq.resolveLocalQueries;
    hasLocalResolver = config.services.bind.enable || dnsmasqResolve;
  
  in
  
  {
  
negative.code:       '';
      };
  
      networking.resolvconfOptions = lib.mkOption {
        type = types.lines;
        default = "";
        example = "ndots:1 rotate";
        description = ''
          Set the options in <filename>/etc/resolv.conf</filename>.
        '';
      };
  
      networking.proxy = {
  
  