# File lib/Dnsruby/Config.rb, line 180
    def add_nameserver(ns)
      if (ns.kind_of?String) 
        ns=[ns]
      end
      check_ns(ns)
      ns.reverse_each do |n|
        if (!@nameserver.include?(n))
          self.nameserver=[n]+@nameserver
        end
      end
    end